def tags(file, order): while True: reader = BitstreamReader(file, order) # read all the tags in an IFD tag_count = reader.read(16) sub_reader = reader.substream(tag_count * 12) next_ifd = reader.read(32) for i in range(tag_count): (tag_code, tag_datatype, tag_value_count) = sub_reader.parse("16u 16u 32u") if tag_datatype == 1: # BYTE type tag_struct = "8u" * tag_value_count elif tag_datatype == 3: # SHORT type tag_struct = "16u" * tag_value_count elif tag_datatype == 4: # LONG type tag_struct = "32u" * tag_value_count else: # all other types tag_struct = "4b" if format_size(tag_struct) <= 32: yield (tag_code, sub_reader.parse(tag_struct)) sub_reader.skip(32 - format_size(tag_struct)) else: offset = sub_reader.read(32) file.seek(offset, 0) yield (tag_code, BitstreamReader(file, order).parse(tag_struct)) if next_ifd != 0: file.seek(next_ifd, 0) else: break
def get_metadata(self): """returns a MetaData object, or None raises IOError if unable to read the file""" from cStringIO import StringIO from audiotools.bitstream import BitstreamReader from audiotools.ogg import PacketReader, PageReader from audiotools.vorbiscomment import VorbisComment reader = PacketReader(PageReader(open(self.filename, "rb"))) identification = reader.read_packet() comment = BitstreamReader(StringIO(reader.read_packet()), True) (packet_type, packet_header) = comment.parse("8u 6b") if ((packet_type == 3) and (packet_header == 'vorbis')): vendor_string = \ comment.read_bytes(comment.read(32)).decode('utf-8') comment_strings = [ comment.read_bytes(comment.read(32)).decode('utf-8') for i in xrange(comment.read(32))] if (comment.read(1) == 1): # framing bit return VorbisComment(comment_strings, vendor_string) else: return None else: return None
def get_replay_gain(self): """returns a ReplayGain object of our ReplayGain values returns None if we have no values may raise IOError if unable to read the file""" from audiotools import ReplayGain try: rg = BitstreamReader(self.get_block(b"RG"), False) except KeyError: return None version = rg.read(8) if version != 1: return None gain_title = rg.read(16) peak_title = rg.read(16) gain_album = rg.read(16) peak_album = rg.read(16) if ((gain_title == 0) and (peak_title == 0) and (gain_album == 0) and (peak_album == 0)): return None else: return ReplayGain( track_gain=64.82 - float(gain_title) / 256, track_peak=(10 ** (float(peak_title) / 256 / 20)) / 2 ** 15, album_gain=64.82 - float(gain_album) / 256, album_peak=(10 ** (float(peak_album) / 256 / 20)) / 2 ** 15)
def get_metadata(self): """returns a MetaData object, or None raises IOError if unable to read the file""" from io import BytesIO from audiotools.bitstream import BitstreamReader from audiotools.ogg import PacketReader, PageReader reader = PacketReader(PageReader(open(self.filename, "rb"))) identification = reader.read_packet() comment = BitstreamReader(BytesIO(reader.read_packet()), True) if (comment.read_bytes(8) == "OpusTags"): vendor_string = \ comment.read_bytes(comment.read(32)).decode('utf-8') comment_strings = [ comment.read_bytes(comment.read(32)).decode('utf-8') for i in range(comment.read(32)) ] return VorbisComment(comment_strings, vendor_string) else: return None
def get_replay_gain(self): """returns a ReplayGain object of our ReplayGain values returns None if we have no values may raise IOError if unable to read the file""" from audiotools import ReplayGain try: rg = BitstreamReader(self.get_block(b"RG"), False) except KeyError: return None version = rg.read(8) if version != 1: return None gain_title = rg.read(16) peak_title = rg.read(16) gain_album = rg.read(16) peak_album = rg.read(16) if ((gain_title == 0) and (peak_title == 0) and (gain_album == 0) and (peak_album == 0)): return None else: return ReplayGain( track_gain=64.82 - float(gain_title) / 256, track_peak=(10**(float(peak_title) / 256 / 20)) / 2**15, album_gain=64.82 - float(gain_album) / 256, album_peak=(10**(float(peak_album) / 256 / 20)) / 2**15)
def __read_identification__(self): from .bitstream import BitstreamReader f = open(self.filename, "rb") try: ogg_reader = BitstreamReader(f, 1) (magic_number, version, header_type, granule_position, self.__serial_number__, page_sequence_number, checksum, segment_count) = ogg_reader.parse("4b 8u 8u 64S 32u 32u 32u 8u") if (magic_number != 'OggS'): from .text import ERR_OGG_INVALID_MAGIC_NUMBER raise InvalidFLAC(ERR_OGG_INVALID_MAGIC_NUMBER) if (version != 0): from .text import ERR_OGG_INVALID_VERSION raise InvalidFLAC(ERR_OGG_INVALID_VERSION) segment_length = ogg_reader.read(8) (vorbis_type, header, version, self.__channels__, self.__sample_rate__, maximum_bitrate, nominal_bitrate, minimum_bitrate, blocksize0, blocksize1, framing) = ogg_reader.parse( "8u 6b 32u 8u 32u 32u 32u 32u 4u 4u 1u") if (vorbis_type != 1): from .text import ERR_VORBIS_INVALID_TYPE raise InvalidVorbis(ERR_VORBIS_INVALID_TYPE) if (header != 'vorbis'): from .text import ERR_VORBIS_INVALID_HEADER raise InvalidVorbis(ERR_VORBIS_INVALID_HEADER) if (version != 0): from .text import ERR_VORBIS_INVALID_VERSION raise InvalidVorbis(ERR_VORBIS_INVALID_VERSION) if (framing != 1): from .text import ERR_VORBIS_INVALID_FRAMING_BIT raise InvalidVorbis(ERR_VORBIS_INVALID_FRAMING_BIT) finally: f.close()
def get_metadata(self): """returns a MetaData object, or None raises IOError if unable to read the file""" from io import BytesIO from audiotools.bitstream import BitstreamReader from audiotools.ogg import PacketReader, PageReader from audiotools.vorbiscomment import VorbisComment with PacketReader(PageReader(open(self.filename, "rb"))) as reader: identification = reader.read_packet() comment = BitstreamReader(BytesIO(reader.read_packet()), True) vendor_string = \ comment.read_bytes(comment.read(32)).decode('utf-8') comment_strings = [ comment.read_bytes(comment.read(32)).decode('utf-8') for i in range(comment.read(32))] return VorbisComment(comment_strings, vendor_string)
def get_metadata(self): """returns a MetaData object, or None raises IOError if unable to read the file""" from audiotools.ogg import PacketReader,PageReader from cStringIO import StringIO from audiotools.bitstream import BitstreamReader packets = PacketReader(PageReader(open(self.filename, "rb"))) identification = packets.read_packet() comment = BitstreamReader(StringIO(packets.read_packet()), True) if (comment.read_bytes(8) == "OpusTags"): vendor_string = \ comment.read_bytes(comment.read(32)).decode('utf-8') comment_strings = [ comment.read_bytes(comment.read(32)).decode('utf-8') for i in xrange(comment.read(32))] return VorbisComment(comment_strings, vendor_string) else: return None
def __init__(self, filename): """filename is a plain string""" AudioFile.__init__(self, filename) try: block = BitstreamReader(self.get_block(b"SH"), False) crc = block.read(32) if block.read(8) != 8: from audiotools.text import ERR_MPC_INVALID_VERSION raise InvalidMPC(ERR_MPC_INVALID_VERSION) self.__samples__ = int(MPC_Size.parse(block)) beg_silence = int(MPC_Size.parse(block)) self.__sample_rate__ = \ [44100, 48000, 37800, 32000][block.read(3)] max_band = block.read(5) + 1 self.__channels__ = block.read(4) + 1 ms = block.read(1) block_pwr = block.read(3) * 2 except IOError as err: raise InvalidMPC(str(err))
class FlacDecoder: CHANNEL_COUNT = [1, 2, 3, 4, 5, 6, 7, 8, 2, 2, 2, None, None, None, None, None] (SUBFRAME_CONSTANT, SUBFRAME_VERBATIM, SUBFRAME_FIXED, SUBFRAME_LPC) = range(4) def __init__(self, filename, channel_mask): self.reader = BitstreamReader(open(filename, "rb"), 0) if (self.reader.read_bytes(4) != 'fLaC'): raise ValueError("invalid FLAC file") self.current_md5sum = md5() #locate the STREAMINFO, #which is sometimes needed to handle non-subset streams for (block_id, block_size, block_reader) in self.metadata_blocks(self.reader): if (block_id == 0): #read STREAMINFO self.minimum_block_size = block_reader.read(16) self.maximum_block_size = block_reader.read(16) self.minimum_frame_size = block_reader.read(24) self.maximum_frame_size = block_reader.read(24) self.sample_rate = block_reader.read(20) self.channels = block_reader.read(3) + 1 self.channel_mask = channel_mask self.bits_per_sample = block_reader.read(5) + 1 self.total_frames = block_reader.read64(36) self.md5sum = block_reader.read_bytes(16) #these are frame header lookup tables #which vary slightly depending on STREAMINFO's values self.BLOCK_SIZE = [self.maximum_block_size, 192, 576, 1152, 2304, 4608, None, None, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768] self.SAMPLE_RATE = [self.sample_rate, 88200, 176400, 192000, 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000, None, None, None, None] self.BITS_PER_SAMPLE = [self.bits_per_sample, 8, 12, None, 16, 20, 24, None] def metadata_blocks(self, reader): """yields a (block_id, block_size, block_reader) tuple per metadata block where block_reader is a BitstreamReader substream""" (last_block, block_id, block_size) = self.reader.parse("1u 7u 24u") while (last_block == 0): yield (block_id, block_size, self.reader.substream(block_size)) (last_block, block_id, block_size) = self.reader.parse("1u 7u 24u") else: yield (block_id, block_size, self.reader.substream(block_size)) def read(self, pcm_frames): #if the stream is exhausted, #verify its MD5 sum and return an empty pcm.FrameList object if (self.total_frames < 1): if (self.md5sum == self.current_md5sum.digest()): return from_list([], self.channels, self.bits_per_sample, True) else: raise ValueError("MD5 checksum mismatch") crc16 = CRC16() self.reader.add_callback(crc16.update) #fetch the decoding parameters from the frame header (block_size, channel_assignment, bits_per_sample) = self.read_frame_header() channel_count = self.CHANNEL_COUNT[channel_assignment] if (channel_count is None): raise ValueError("invalid channel assignment") #channel data will be a list of signed sample lists, one per channel #such as [[1, 2, 3, ...], [4, 5, 6, ...]] for a 2 channel stream channel_data = [] for channel_number in xrange(channel_count): if ((channel_assignment == 0x8) and (channel_number == 1)): #for left-difference assignment #the difference channel has 1 additional bit channel_data.append(self.read_subframe(block_size, bits_per_sample + 1)) elif ((channel_assignment == 0x9) and (channel_number == 0)): #for difference-right assignment #the difference channel has 1 additional bit channel_data.append(self.read_subframe(block_size, bits_per_sample + 1)) elif ((channel_assignment == 0xA) and (channel_number == 1)): #for mid-side assignment #the side channel has 1 additional bit channel_data.append(self.read_subframe(block_size, bits_per_sample + 1)) else: #otherwise, use the frame's bits-per-sample value channel_data.append(self.read_subframe(block_size, bits_per_sample)) #one all the subframes have been decoded, #reconstruct them depending on the channel assignment if (channel_assignment == 0x8): #left-difference samples = [] for (left, difference) in zip(*channel_data): samples.append(left) samples.append(left - difference) elif (channel_assignment == 0x9): #difference-right samples = [] for (difference, right) in zip(*channel_data): samples.append(difference + right) samples.append(right) elif (channel_assignment == 0xA): #mid-side samples = [] for (mid, side) in zip(*channel_data): samples.append((((mid * 2) + (side % 2)) + side) / 2) samples.append((((mid * 2) + (side % 2)) - side) / 2) else: #independent samples = [0] * block_size * channel_count for (i, channel) in enumerate(channel_data): samples[i::channel_count] = channel self.reader.byte_align() #read and verify the frame's trailing CRC-16 footer self.reader.read(16) self.reader.pop_callback() if (int(crc16) != 0): raise ValueError("CRC16 mismatch in frame footer") #deduct the amount of PCM frames from the remaining amount self.total_frames -= block_size #build a pcm.FrameList object from the combined samples framelist = from_list(samples, channel_count, bits_per_sample, True) #update the running MD5 sum calculation with the frame's data self.current_md5sum.update(framelist.to_bytes(0, 1)) #and finally return the frame data return framelist def read_frame_header(self): crc8 = CRC8() self.reader.add_callback(crc8.update) #read the 32-bit FLAC frame header sync_code = self.reader.read(14) if (sync_code != 0x3FFE): raise ValueError("invalid sync code") self.reader.skip(1) blocking_strategy = self.reader.read(1) block_size_bits = self.reader.read(4) sample_rate_bits = self.reader.read(4) channel_assignment = self.reader.read(4) bits_per_sample_bits = self.reader.read(3) self.reader.skip(1) #the frame number is a UTF-8 encoded value #which takes a variable number of whole bytes frame_number = self.read_utf8() #unpack the 4 bit block size field #which is the total PCM frames in the FLAC frame #and may require up to 16 more bits if the frame is usually-sized #(which typically happens at the end of the stream) if (block_size_bits == 0x6): block_size = self.reader.read(8) + 1 elif (block_size_bits == 0x7): block_size = self.reader.read(16) + 1 else: block_size = self.BLOCK_SIZE[block_size_bits] #unpack the 4 bit sample rate field #which is used for playback, but not needed for decoding #and may require up to 16 more bits #if the stream has a particularly unusual sample rate if (sample_rate_bits == 0xC): sample_rate = self.reader.read(8) * 1000 elif (sample_rate_bits == 0xD): sample_rate = self.reader.read(16) elif (sample_rate_bits == 0xE): sample_rate = self.reader.read(16) * 10 elif (sample_rate_bits == 0xF): raise ValueError("invalid sample rate") else: sample_rate = self.SAMPLE_RATE[sample_rate_bits] #unpack the 3 bit bits-per-sample field #this never requires additional bits if ((bits_per_sample_bits == 0x3) or (bits_per_sample_bits == 0x7)): raise ValueError("invalid bits per sample") else: bits_per_sample = self.BITS_PER_SAMPLE[bits_per_sample_bits] #read and verify frame's CRC-8 value self.reader.read(8) self.reader.pop_callback() if (int(crc8) != 0): raise ValueError("CRC8 mismatch in frame header") return (block_size, channel_assignment, bits_per_sample) def read_subframe_header(self): """returns a tuple of (subframe_type, subframe_order, wasted_bps)""" self.reader.skip(1) subframe_type = self.reader.read(6) if (self.reader.read(1) == 1): wasted_bps = self.reader.unary(1) + 1 else: wasted_bps = 0 #extract "order" value from 6 bit subframe type, if necessary if (subframe_type == 0): return (self.SUBFRAME_CONSTANT, None, wasted_bps) elif (subframe_type == 1): return (self.SUBFRAME_VERBATIM, None, wasted_bps) elif ((subframe_type & 0x38) == 0x08): return (self.SUBFRAME_FIXED, subframe_type & 0x07, wasted_bps) elif ((subframe_type & 0x20) == 0x20): return (self.SUBFRAME_LPC, (subframe_type & 0x1F) + 1, wasted_bps) else: raise ValueError("invalid subframe type") def read_subframe(self, block_size, bits_per_sample): (subframe_type, subframe_order, wasted_bps) = self.read_subframe_header() #read a list of signed sample values #depending on the subframe type, block size, #adjusted bits per sample and optional subframe order if (subframe_type == self.SUBFRAME_CONSTANT): subframe_samples = self.read_constant_subframe( block_size, bits_per_sample - wasted_bps) elif (subframe_type == self.SUBFRAME_VERBATIM): subframe_samples = self.read_verbatim_subframe( block_size, bits_per_sample - wasted_bps) elif (subframe_type == self.SUBFRAME_FIXED): subframe_samples = self.read_fixed_subframe( block_size, bits_per_sample - wasted_bps, subframe_order) else: subframe_samples = self.read_lpc_subframe( block_size, bits_per_sample - wasted_bps, subframe_order) #account for wasted bits-per-sample, if necessary if (wasted_bps): return [sample << wasted_bps for sample in subframe_samples] else: return subframe_samples def read_constant_subframe(self, block_size, bits_per_sample): sample = self.reader.read_signed(bits_per_sample) return [sample] * block_size def read_verbatim_subframe(self, block_size, bits_per_sample): return [self.reader.read_signed(bits_per_sample) for x in xrange(block_size)] def read_fixed_subframe(self, block_size, bits_per_sample, order): #"order" number of warm-up samples samples = [self.reader.read_signed(bits_per_sample) for i in xrange(order)] #"block_size" - "order" number of residual values residuals = self.read_residual(block_size, order) #which are applied to the warm-up samples #depending on the FIXED subframe order #and results in "block_size" number of total samples if (order == 0): return residuals elif (order == 1): for residual in residuals: samples.append( samples[-1] + residual) return samples elif (order == 2): for residual in residuals: samples.append( (2 * samples[-1]) - samples[-2] + residual) return samples elif (order == 3): for residual in residuals: samples.append( (3 * samples[-1]) - (3 * samples[-2]) + samples[-3] + residual) return samples elif (order == 4): for residual in residuals: samples.append( (4 * samples[-1]) - (6 * samples[-2]) + (4 * samples[-3]) - samples[-4] + residual) return samples else: raise ValueError("unsupported FIXED subframe order") def read_lpc_subframe(self, block_size, bits_per_sample, order): #"order" number of warm-up samples samples = [self.reader.read_signed(bits_per_sample) for i in xrange(order)] #the size of each QLP coefficient, in bits qlp_precision = self.reader.read(4) #the amount of right shift to apply #during LPC calculation #(though this is a signed value, negative shifts are noops # in the reference FLAC decoder) qlp_shift_needed = max(self.reader.read_signed(5), 0) #"order" number of signed QLP coefficients qlp_coeffs = [self.reader.read_signed(qlp_precision + 1) for i in xrange(order)] #QLP coefficients are applied in reverse order qlp_coeffs.reverse() #"block_size" - "order" number of residual values residuals = self.read_residual(block_size, order) #which are applied to the running LPC calculation for residual in residuals: samples.append((sum([coeff * sample for (coeff, sample) in zip(qlp_coeffs, samples[-order:])]) >> qlp_shift_needed) + residual) return samples def read_residual(self, block_size, order): residuals = [] coding_method = self.reader.read(2) partition_order = self.reader.read(4) #each parititon contains block_size / 2 ** partition_order #number of residuals for partition_number in xrange(2 ** partition_order): if (partition_number == 0): #except for the first partition #which contains "order" less than the rest residuals.extend( self.read_residual_partition( coding_method, (block_size / 2 ** partition_order) - order)) else: residuals.extend( self.read_residual_partition( coding_method, block_size / 2 ** partition_order)) return residuals def read_residual_partition(self, coding_method, residual_count): if (coding_method == 0): #the Rice parameters determines the number of #least-significant bits to read for each residual rice_parameter = self.reader.read(4) if (rice_parameter == 0xF): escape_code = self.reader.read(5) return [self.reader.read_signed(escape_code) for i in xrange(residual_count)] elif (coding_method == 1): #24 bps streams may use a 5-bit Rice parameter #for better compression rice_parameter = self.reader.read(5) if (rice_parameter == 0x1F): escape_code = self.reader.read(5) return [self.reader.read_signed(escape_code) for i in xrange(residual_count)] else: raise ValueError("invalid Rice coding parameter") #a list of signed residual values partition_residuals = [] for i in xrange(residual_count): msb = self.reader.unary(1) # most-significant bits lsb = self.reader.read(rice_parameter) # least-significant bits value = (msb << rice_parameter) | lsb # combined into a value if (value & 1): # whose least-significant bit is the sign value partition_residuals.append(-(value >> 1) - 1) else: partition_residuals.append(value >> 1) return partition_residuals def read_utf8(self): total_bytes = self.reader.unary(0) value = self.reader.read(7 - total_bytes) while (total_bytes > 1): value = ((value << 6) | self.reader.parse("2p 6u")[0]) total_bytes -= 1 return value def close(self): self.reader.close()
class ALACDecoder(object): def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), False) self.reader.mark() try: # locate the "alac" atom # which is full of required decoding parameters try: stsd = self.find_sub_atom(b"moov", b"trak", b"mdia", b"minf", b"stbl", b"stsd") except KeyError: raise ValueError("required stsd atom not found") (stsd_version, descriptions) = stsd.parse("8u 24p 32u") (alac1, alac2, self.samples_per_frame, self.bits_per_sample, self.history_multiplier, self.initial_history, self.maximum_k, self.channels, self.sample_rate) = stsd.parse( # ignore much of the stuff in the "high" ALAC atom "32p 4b 6P 16p 16p 16p 4P 16p 16p 16p 16p 4P" + # and use the attributes in the "low" ALAC atom instead "32p 4b 4P 32u 8p 8u 8u 8u 8u 8u 16p 32p 32p 32u") self.channel_mask = { 1: 0x0004, 2: 0x0003, 3: 0x0007, 4: 0x0107, 5: 0x0037, 6: 0x003F, 7: 0x013F, 8: 0x00FF }.get(self.channels, 0) if ((alac1 != b'alac') or (alac2 != b'alac')): raise ValueError("Invalid alac atom") # also locate the "mdhd" atom # which contains the stream's length in PCM frames self.reader.rewind() mdhd = self.find_sub_atom(b"moov", b"trak", b"mdia", b"mdhd") (version, ) = mdhd.parse("8u 24p") if (version == 0): (self.total_pcm_frames, ) = mdhd.parse("32p 32p 32p 32u 2P 16p") elif (version == 1): (self.total_pcm_frames, ) = mdhd.parse("64p 64p 32p 64U 2P 16p") else: raise ValueError("invalid mdhd version") # finally, set our stream to the "mdat" atom self.reader.rewind() (atom_size, atom_name) = self.reader.parse("32u 4b") while (atom_name != b"mdat"): self.reader.skip_bytes(atom_size - 8) (atom_size, atom_name) = self.reader.parse("32u 4b") finally: self.reader.unmark() def find_sub_atom(self, *atom_names): reader = self.reader for (last, next_atom) in iter_last(iter(atom_names)): try: (length, stream_atom) = reader.parse("32u 4b") while (stream_atom != next_atom): reader.skip_bytes(length - 8) (length, stream_atom) = reader.parse("32u 4b") if (last): return reader.substream(length - 8) else: reader = reader.substream(length - 8) except IOError: raise KeyError(next_atom) def read(self, pcm_frames): # if the stream is exhausted, return an empty pcm.FrameList object if (self.total_pcm_frames == 0): return empty_framelist(self.channels, self.bits_per_sample) # otherwise, read one ALAC frameset's worth of frame data frameset_data = [] frame_channels = self.reader.read(3) + 1 while (frame_channels != 0x8): frameset_data.extend(self.read_frame(frame_channels)) frame_channels = self.reader.read(3) + 1 self.reader.byte_align() # reorder the frameset to Wave order, depending on channel count if ((self.channels == 1) or (self.channels == 2)): pass elif (self.channels == 3): frameset_data = [ frameset_data[1], frameset_data[2], frameset_data[0] ] elif (self.channels == 4): frameset_data = [ frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[3] ] elif (self.channels == 5): frameset_data = [ frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[3], frameset_data[4] ] elif (self.channels == 6): frameset_data = [ frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[5], frameset_data[3], frameset_data[4] ] elif (self.channels == 7): frameset_data = [ frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[6], frameset_data[3], frameset_data[4], frameset_data[5] ] elif (self.channels == 8): frameset_data = [ frameset_data[3], frameset_data[4], frameset_data[0], frameset_data[7], frameset_data[5], frameset_data[6], frameset_data[1], frameset_data[2] ] else: raise ValueError("unsupported channel count") framelist = from_channels([ from_list(channel, 1, self.bits_per_sample, True) for channel in frameset_data ]) # deduct PCM frames from remainder self.total_pcm_frames -= framelist.frames # return samples as a pcm.FrameList object return framelist def read_frame(self, channel_count): """returns a list of PCM sample lists, one per channel""" # read the ALAC frame header self.reader.skip(16) has_sample_count = self.reader.read(1) uncompressed_lsb_size = self.reader.read(2) uncompressed = self.reader.read(1) if (has_sample_count): sample_count = self.reader.read(32) else: sample_count = self.samples_per_frame if (uncompressed == 1): # if the frame is uncompressed, # read the raw, interlaced samples samples = [ self.reader.read_signed(self.bits_per_sample) for i in range(sample_count * channel_count) ] return [samples[i::channel_count] for i in range(channel_count)] else: # if the frame is compressed, # read the interlacing parameters interlacing_shift = self.reader.read(8) interlacing_leftweight = self.reader.read(8) # subframe headers subframe_headers = [ self.read_subframe_header() for i in range(channel_count) ] # optional uncompressed LSB values if (uncompressed_lsb_size > 0): uncompressed_lsbs = [ self.reader.read(uncompressed_lsb_size * 8) for i in range(sample_count * channel_count) ] else: uncompressed_lsbs = [] sample_size = (self.bits_per_sample - (uncompressed_lsb_size * 8) + channel_count - 1) # and residual blocks residual_blocks = [ self.read_residuals(sample_size, sample_count) for i in range(channel_count) ] # calculate subframe samples based on # subframe header's QLP coefficients and QLP shift-needed decoded_subframes = [ self.decode_subframe(header[0], header[1], sample_size, residuals) for (header, residuals) in zip(subframe_headers, residual_blocks) ] # decorrelate channels according interlacing shift and leftweight decorrelated_channels = self.decorrelate_channels( decoded_subframes, interlacing_shift, interlacing_leftweight) # if uncompressed LSB values are present, # prepend them to each sample of each channel if (uncompressed_lsb_size > 0): channels = [] for (i, channel) in enumerate(decorrelated_channels): assert (len(channel) == len( uncompressed_lsbs[i::channel_count])) channels.append([ s << (uncompressed_lsb_size * 8) | l for (s, l) in zip( channel, uncompressed_lsbs[i::channel_count]) ]) return channels else: return decorrelated_channels def read_subframe_header(self): prediction_type = self.reader.read(4) qlp_shift_needed = self.reader.read(4) rice_modifier = self.reader.read(3) qlp_coefficients = [ self.reader.read_signed(16) for i in range(self.reader.read(5)) ] return (qlp_shift_needed, qlp_coefficients) def read_residuals(self, sample_size, sample_count): residuals = [] history = self.initial_history sign_modifier = 0 i = 0 while (i < sample_count): # get an unsigned residual based on "history" # and on "sample_size" as a lst resort k = min(log2(history // (2**9) + 3), self.maximum_k) unsigned = self.read_residual(k, sample_size) + sign_modifier # clear out old sign modifier, if any sign_modifier = 0 # change unsigned residual to signed residual if (unsigned & 1): residuals.append(-((unsigned + 1) // 2)) else: residuals.append(unsigned // 2) # update history based on unsigned residual if (unsigned <= 0xFFFF): history += ((unsigned * self.history_multiplier) - ((history * self.history_multiplier) >> 9)) else: history = 0xFFFF # if history gets too small, we may have a block of 0 samples # which can be compressed more efficiently if ((history < 128) and ((i + 1) < sample_count)): zeroes_k = min(7 - log2(history) + ((history + 16) // 64), self.maximum_k) zero_residuals = self.read_residual(zeroes_k, 16) if (zero_residuals > 0): residuals.extend([0] * zero_residuals) i += zero_residuals history = 0 if (zero_residuals <= 0xFFFF): sign_modifier = 1 i += 1 return residuals def read_residual(self, k, sample_size): msb = self.reader.read_huffman_code(RESIDUAL) if (msb == -1): return self.reader.read(sample_size) elif (k == 0): return msb else: lsb = self.reader.read(k) if (lsb > 1): return msb * ((1 << k) - 1) + (lsb - 1) elif (lsb == 1): self.reader.unread(1) return msb * ((1 << k) - 1) else: self.reader.unread(0) return msb * ((1 << k) - 1) def decode_subframe(self, qlp_shift_needed, qlp_coefficients, sample_size, residuals): # first sample is always copied verbatim samples = [residuals.pop(0)] if (len(qlp_coefficients) < 31): # the next "coefficient count" samples # are applied as differences to the previous for i in range(len(qlp_coefficients)): samples.append( truncate_bits(samples[-1] + residuals.pop(0), sample_size)) # remaining samples are processed much like LPC for residual in residuals: base_sample = samples[-len(qlp_coefficients) - 1] lpc_sum = sum([(s - base_sample) * c for (s, c) in zip(samples[-len(qlp_coefficients):], reversed(qlp_coefficients))]) outval = (1 << (qlp_shift_needed - 1)) + lpc_sum outval >>= qlp_shift_needed samples.append( truncate_bits(outval + residual + base_sample, sample_size)) buf = samples[-len(qlp_coefficients) - 2:-1] # error value then adjusts the coefficients table if (residual > 0): predictor_num = len(qlp_coefficients) - 1 while ((predictor_num >= 0) and residual > 0): val = (buf[0] - buf[len(qlp_coefficients) - predictor_num]) sign = sign_only(val) qlp_coefficients[predictor_num] -= sign val *= sign residual -= ((val >> qlp_shift_needed) * (len(qlp_coefficients) - predictor_num)) predictor_num -= 1 elif (residual < 0): # the same as above, but we break if residual goes positive predictor_num = len(qlp_coefficients) - 1 while ((predictor_num >= 0) and residual < 0): val = (buf[0] - buf[len(qlp_coefficients) - predictor_num]) sign = -sign_only(val) qlp_coefficients[predictor_num] -= sign val *= sign residual -= ((val >> qlp_shift_needed) * (len(qlp_coefficients) - predictor_num)) predictor_num -= 1 else: # residuals are encoded as simple difference values for residual in residuals: samples.append( truncate_bits(samples[-1] + residual, sample_size)) return samples def decorrelate_channels(self, channel_data, interlacing_shift, interlacing_leftweight): if (len(channel_data) != 2): return channel_data elif (interlacing_leftweight == 0): return channel_data else: left = [] right = [] for (ch1, ch2) in zip(*channel_data): right.append(ch1 - ((ch2 * interlacing_leftweight) // (2**interlacing_shift))) left.append(ch2 + right[-1]) return [left, right] def close(self): self.reader.close() def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close()
def __parse_info__(self): """generates a cache of sample_rate, bits-per-sample, etc""" import re import os.path from audiotools.bitstream import BitstreamReader if (len(self.tracks) == 0): return # Why is this post-init processing necessary? # DVDATrack references DVDATitle # so a DVDATitle must exist when DVDATrack is initialized. # But because reading this info requires knowing the sector # of the first track, we wind up with a circular dependency. # Doing a "post-process" pass fixes that problem. # find the AOB file of the title's first track track_sector = self[0].first_sector titleset = re.compile("ATS_%2.2d_\\d\\.AOB" % (self.titleset)) for aob_path in sorted([self.dvdaudio.files[key] for key in self.dvdaudio.files.keys() if (titleset.match(key))]): aob_sectors = os.path.getsize(aob_path) // DVDAudio.SECTOR_SIZE if (track_sector > aob_sectors): track_sector -= aob_sectors else: break else: from audiotools.text import ERR_DVDA_NO_TRACK_SECTOR raise ValueError(ERR_DVDA_NO_TRACK_SECTOR) # open that AOB file and seek to that track's first sector aob_file = open(aob_path, 'rb') try: aob_file.seek(track_sector * DVDAudio.SECTOR_SIZE) aob_reader = BitstreamReader(aob_file, 0) # read and validate the pack header # (there's one pack header per sector, at the sector's start) (sync_bytes, marker1, current_pts_high, marker2, current_pts_mid, marker3, current_pts_low, marker4, scr_extension, marker5, bit_rate, marker6, stuffing_length) = aob_reader.parse( "32u 2u 3u 1u 15u 1u 15u 1u 9u 1u 22u 2u 5p 3u") aob_reader.skip_bytes(stuffing_length) if (sync_bytes != 0x1BA): from audiotools.text import ERR_DVDA_INVALID_AOB_SYNC raise InvalidDVDA(ERR_DVDA_INVALID_AOB_SYNC) if (((marker1 != 1) or (marker2 != 1) or (marker3 != 1) or (marker4 != 1) or (marker5 != 1) or (marker6 != 3))): from audiotools.text import ERR_DVDA_INVALID_AOB_MARKER raise InvalidDVDA(ERR_DVDA_INVALID_AOB_MARKER) packet_pts = ((current_pts_high << 30) | (current_pts_mid << 15) | current_pts_low) # skip packets until one with a stream ID of 0xBD is found (start_code, stream_id, packet_length) = aob_reader.parse("24u 8u 16u") if (start_code != 1): from audiotools.text import ERR_DVDA_INVALID_AOB_START raise InvalidDVDA(ERR_DVDA_INVALID_AOB_START) while (stream_id != 0xBD): aob_reader.skip_bytes(packet_length) (start_code, stream_id, packet_length) = aob_reader.parse("24u 8u 16u") if (start_code != 1): from audiotools.text import ERR_DVDA_INVALID_AOB_START raise InvalidDVDA(ERR_DVDA_INVALID_AOB_START) # parse the PCM/MLP header in the packet data (pad1_size,) = aob_reader.parse("16p 8u") aob_reader.skip_bytes(pad1_size) (stream_id, crc) = aob_reader.parse("8u 8u 8p") if (stream_id == 0xA0): # PCM # read a PCM reader (pad2_size, first_audio_frame, padding2, group1_bps, group2_bps, group1_sample_rate, group2_sample_rate, padding3, channel_assignment) = aob_reader.parse( "8u 16u 8u 4u 4u 4u 4u 8u 8u") else: # MLP aob_reader.skip_bytes(aob_reader.read(8)) # skip pad2 # read a total frame size + MLP major sync header (total_frame_size, sync_words, stream_type, group1_bps, group2_bps, group1_sample_rate, group2_sample_rate, unknown1, channel_assignment, unknown2) = aob_reader.parse( "4p 12u 16p 24u 8u 4u 4u 4u 4u 11u 5u 48u") # return the values indicated by the header self.sample_rate = DVDATrack.SAMPLE_RATE[group1_sample_rate] self.channels = DVDATrack.CHANNELS[channel_assignment] self.channel_mask = DVDATrack.CHANNEL_MASK[channel_assignment] self.bits_per_sample = DVDATrack.BITS_PER_SAMPLE[group1_bps] self.stream_id = stream_id finally: aob_file.close()
class ALACDecoder: def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), 0) self.reader.mark() try: #locate the "alac" atom #which is full of required decoding parameters try: stsd = self.find_sub_atom("moov", "trak", "mdia", "minf", "stbl", "stsd") except KeyError: raise ValueError("required stsd atom not found") (stsd_version, descriptions) = stsd.parse("8u 24p 32u") (alac1, alac2, self.samples_per_frame, self.bits_per_sample, self.history_multiplier, self.initial_history, self.maximum_k, self.channels, self.sample_rate) = stsd.parse( #ignore much of the stuff in the "high" ALAC atom "32p 4b 6P 16p 16p 16p 4P 16p 16p 16p 16p 4P" + #and use the attributes in the "low" ALAC atom instead "32p 4b 4P 32u 8p 8u 8u 8u 8u 8u 16p 32p 32p 32u") self.channel_mask = {1: 0x0004, 2: 0x0003, 3: 0x0007, 4: 0x0107, 5: 0x0037, 6: 0x003F, 7: 0x013F, 8: 0x00FF}.get(self.channels, 0) if ((alac1 != 'alac') or (alac2 != 'alac')): raise ValueError("Invalid alac atom") #also locate the "mdhd" atom #which contains the stream's length in PCM frames self.reader.rewind() mdhd = self.find_sub_atom("moov", "trak", "mdia", "mdhd") (version, ) = mdhd.parse("8u 24p") if (version == 0): (self.total_pcm_frames,) = mdhd.parse( "32p 32p 32p 32u 2P 16p") elif (version == 1): (self.total_pcm_frames,) = mdhd.parse( "64p 64p 32p 64U 2P 16p") else: raise ValueError("invalid mdhd version") #finally, set our stream to the "mdat" atom self.reader.rewind() (atom_size, atom_name) = self.reader.parse("32u 4b") while (atom_name != "mdat"): self.reader.skip_bytes(atom_size - 8) (atom_size, atom_name) = self.reader.parse("32u 4b") finally: self.reader.unmark() def find_sub_atom(self, *atom_names): reader = self.reader for (last, next_atom) in iter_last(iter(atom_names)): try: (length, stream_atom) = reader.parse("32u 4b") while (stream_atom != next_atom): reader.skip_bytes(length - 8) (length, stream_atom) = reader.parse("32u 4b") if (last): return reader.substream(length - 8) else: reader = reader.substream(length - 8) except IOError: raise KeyError(next_atom) def read(self, pcm_frames): #if the stream is exhausted, return an empty pcm.FrameList object if (self.total_pcm_frames == 0): return from_list([], self.channels, self.bits_per_sample, True) #otherwise, read one ALAC frameset's worth of frame data frameset_data = [] frame_channels = self.reader.read(3) + 1 while (frame_channels != 0x8): frameset_data.extend(self.read_frame(frame_channels)) frame_channels = self.reader.read(3) + 1 self.reader.byte_align() #reorder the frameset to Wave order, depending on channel count if ((self.channels == 1) or (self.channels == 2)): pass elif (self.channels == 3): frameset_data = [frameset_data[1], frameset_data[2], frameset_data[0]] elif (self.channels == 4): frameset_data = [frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[3]] elif (self.channels == 5): frameset_data = [frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[3], frameset_data[4]] elif (self.channels == 6): frameset_data = [frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[5], frameset_data[3], frameset_data[4]] elif (self.channels == 7): frameset_data = [frameset_data[1], frameset_data[2], frameset_data[0], frameset_data[6], frameset_data[3], frameset_data[4], frameset_data[5]] elif (self.channels == 8): frameset_data = [frameset_data[3], frameset_data[4], frameset_data[0], frameset_data[7], frameset_data[5], frameset_data[6], frameset_data[1], frameset_data[2]] else: raise ValueError("unsupported channel count") framelist = from_channels([from_list(channel, 1, self.bits_per_sample, True) for channel in frameset_data]) #deduct PCM frames from remainder self.total_pcm_frames -= framelist.frames #return samples as a pcm.FrameList object return framelist def read_frame(self, channel_count): """returns a list of PCM sample lists, one per channel""" #read the ALAC frame header self.reader.skip(16) has_sample_count = self.reader.read(1) uncompressed_lsb_size = self.reader.read(2) uncompressed = self.reader.read(1) if (has_sample_count): sample_count = self.reader.read(32) else: sample_count = self.samples_per_frame if (uncompressed == 1): #if the frame is uncompressed, #read the raw, interlaced samples samples = [self.reader.read_signed(self.bits_per_sample) for i in xrange(sample_count * channel_count)] return [samples[i::channel_count] for i in xrange(channel_count)] else: #if the frame is compressed, #read the interlacing parameters interlacing_shift = self.reader.read(8) interlacing_leftweight = self.reader.read(8) #subframe headers subframe_headers = [self.read_subframe_header() for i in xrange(channel_count)] #optional uncompressed LSB values if (uncompressed_lsb_size > 0): uncompressed_lsbs = [ self.reader.read(uncompressed_lsb_size * 8) for i in xrange(sample_count * channel_count)] else: uncompressed_lsbs = [] sample_size = (self.bits_per_sample - (uncompressed_lsb_size * 8) + channel_count - 1) #and residual blocks residual_blocks = [self.read_residuals(sample_size, sample_count) for i in xrange(channel_count)] #calculate subframe samples based on #subframe header's QLP coefficients and QLP shift-needed decoded_subframes = [self.decode_subframe(header[0], header[1], sample_size, residuals) for (header, residuals) in zip(subframe_headers, residual_blocks)] #decorrelate channels according interlacing shift and leftweight decorrelated_channels = self.decorrelate_channels( decoded_subframes, interlacing_shift, interlacing_leftweight) #if uncompressed LSB values are present, #prepend them to each sample of each channel if (uncompressed_lsb_size > 0): channels = [] for (i, channel) in enumerate(decorrelated_channels): assert(len(channel) == len(uncompressed_lsbs[i::channel_count])) channels.append([s << (uncompressed_lsb_size * 8) | l for (s, l) in zip(channel, uncompressed_lsbs[i::channel_count])]) return channels else: return decorrelated_channels def read_subframe_header(self): prediction_type = self.reader.read(4) qlp_shift_needed = self.reader.read(4) rice_modifier = self.reader.read(3) qlp_coefficients = [self.reader.read_signed(16) for i in xrange(self.reader.read(5))] return (qlp_shift_needed, qlp_coefficients) def read_residuals(self, sample_size, sample_count): residuals = [] history = self.initial_history sign_modifier = 0 i = 0 while (i < sample_count): #get an unsigned residual based on "history" #and on "sample_size" as a lst resort k = min(log2(history / (2 ** 9) + 3), self.maximum_k) unsigned = self.read_residual(k, sample_size) + sign_modifier #clear out old sign modifier, if any sign_modifier = 0 #change unsigned residual to signed residual if (unsigned & 1): residuals.append(-((unsigned + 1) / 2)) else: residuals.append(unsigned / 2) #update history based on unsigned residual if (unsigned <= 0xFFFF): history += ((unsigned * self.history_multiplier) - ((history * self.history_multiplier) >> 9)) else: history = 0xFFFF #if history gets too small, we may have a block of 0 samples #which can be compressed more efficiently if ((history < 128) and ((i + 1) < sample_count)): zeroes_k = min(7 - log2(history) + ((history + 16) / 64), self.maximum_k) zero_residuals = self.read_residual(zeroes_k, 16) if (zero_residuals > 0): residuals.extend([0] * zero_residuals) i += zero_residuals history = 0 if (zero_residuals <= 0xFFFF): sign_modifier = 1 i += 1 return residuals def read_residual(self, k, sample_size): msb = self.reader.limited_unary(0, 9) if (msb is None): return self.reader.read(sample_size) elif (k == 0): return msb else: lsb = self.reader.read(k) if (lsb > 1): return msb * ((1 << k) - 1) + (lsb - 1) elif (lsb == 1): self.reader.unread(1) return msb * ((1 << k) - 1) else: self.reader.unread(0) return msb * ((1 << k) - 1) def decode_subframe(self, qlp_shift_needed, qlp_coefficients, sample_size, residuals): #first sample is always copied verbatim samples = [residuals.pop(0)] if (len(qlp_coefficients) < 31): #the next "coefficient count" samples #are applied as differences to the previous for i in xrange(len(qlp_coefficients)): samples.append(truncate_bits(samples[-1] + residuals.pop(0), sample_size)) #remaining samples are processed much like LPC for residual in residuals: base_sample = samples[-len(qlp_coefficients) - 1] lpc_sum = sum([(s - base_sample) * c for (s, c) in zip(samples[-len(qlp_coefficients):], reversed(qlp_coefficients))]) outval = (1 << (qlp_shift_needed - 1)) + lpc_sum outval >>= qlp_shift_needed samples.append(truncate_bits(outval + residual + base_sample, sample_size)) buf = samples[-len(qlp_coefficients) - 2:-1] #error value then adjusts the coefficients table if (residual > 0): predictor_num = len(qlp_coefficients) - 1 while ((predictor_num >= 0) and residual > 0): val = (buf[0] - buf[len(qlp_coefficients) - predictor_num]) sign = sign_only(val) qlp_coefficients[predictor_num] -= sign val *= sign residual -= ((val >> qlp_shift_needed) * (len(qlp_coefficients) - predictor_num)) predictor_num -= 1 elif (residual < 0): #the same as above, but we break if residual goes positive predictor_num = len(qlp_coefficients) - 1 while ((predictor_num >= 0) and residual < 0): val = (buf[0] - buf[len(qlp_coefficients) - predictor_num]) sign = -sign_only(val) qlp_coefficients[predictor_num] -= sign val *= sign residual -= ((val >> qlp_shift_needed) * (len(qlp_coefficients) - predictor_num)) predictor_num -= 1 else: #residuals are encoded as simple difference values for residual in residuals: samples.append(truncate_bits(samples[-1] + residual, sample_size)) return samples def decorrelate_channels(self, channel_data, interlacing_shift, interlacing_leftweight): if (len(channel_data) != 2): return channel_data elif (interlacing_leftweight == 0): return channel_data else: left = [] right = [] for (ch1, ch2) in zip(*channel_data): right.append(ch1 - ((ch2 * interlacing_leftweight) / (2 ** interlacing_shift))) left.append(ch2 + right[-1]) return [left, right] def close(self): pass
class TTADecoder(object): def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), True) crc = CRC32() self.reader.add_callback(crc.update) # read the header (signature, format_, self.channels, self.bits_per_sample, self.sample_rate, self.total_pcm_frames) = self.reader.parse("4b 16u 16u 16u 32u 32u") self.reader.pop_callback() header_crc = self.reader.read(32) if (int(crc) != header_crc): raise ValueError("CRC32 mismatch in header (0x%8.8X != 0x%8.8X)" % (header_crc, int(crc))) self.channel_mask = {1: 0x4, 2: 0x3}.get(self.channels, 0) total_tta_frames = div_ceil(self.total_pcm_frames * 245, self.sample_rate * 256) self.pcm_frames_per_tta_frame = (self.sample_rate * 256) // 245 # read the seektable crc = CRC32() self.reader.add_callback(crc.update) self.frame_sizes = [ self.reader.read(32) for i in range(total_tta_frames) ] self.reader.pop_callback() seektable_crc = self.reader.read(32) if (int(crc) != seektable_crc): raise ValueError( "CRC32 mismatch in seektable (0x%8.8X != 0x%8.8X)" % (header_crc, int(crc))) self.current_tta_frame = 0 def read(self, pcm_frames): if (self.total_pcm_frames == 0): return FrameList("", self.channels, self.bits_per_sample, True, True) pcm_frames = min(self.pcm_frames_per_tta_frame, self.total_pcm_frames) frame_reader = self.reader.substream( self.frame_sizes[self.current_tta_frame]) crc = CRC32() frame_reader.add_callback(crc.update) self.total_pcm_frames -= pcm_frames self.current_tta_frame += 1 # setup Rice parameters for each channel k0 = [10] * self.channels k1 = [10] * self.channels sum0 = [2**14] * self.channels sum1 = [2**14] * self.channels # list of unfiltered output for each channel unfiltered = [[] for i in range(self.channels)] for f in range(pcm_frames): correlated = [] for (c, ch_output) in enumerate(unfiltered): # read most-significant bits MSB = frame_reader.unary(0) if (MSB == 0): # read least-significant bits unsigned = frame_reader.read(k0[c]) else: # read least-significant bits LSB = frame_reader.read(k1[c]) unshifted = ((MSB - 1) << k1[c]) + LSB unsigned = unshifted + (1 << k0[c]) # adjust sum1 and k1 sum1[c] += (unshifted - (sum1[c] >> 4)) if (sum1[c] < (2**(k1[c] + 4))): k1[c] = max(k1[c] - 1, 0) elif (sum1[c] > (2**(k1[c] + 5))): k1[c] += 1 # adjust sum0 and k0 sum0[c] += (unsigned - (sum0[c] >> 4)) if (sum0[c] < (2**(k0[c] + 4))): k0[c] = max(k0[c] - 1, 0) elif (sum0[c] > (2**(k0[c] + 5))): k0[c] += 1 # apply sign bit if ((unsigned % 2) == 1): # positive ch_output.append((unsigned + 1) // 2) else: # negative ch_output.append(-(unsigned // 2)) # check frame's trailing CRC32 now that reading is finished frame_reader.byte_align() frame_reader.pop_callback() frame_crc = frame_reader.read(32) if (int(crc) != frame_crc): raise ValueError("CRC32 mismatch in frame (0x%8.8X != 0x%8.8X)" % (frame_crc, int(crc))) # run hybrid filter on each channel filtered = [] for unfiltered_ch in unfiltered: filtered.append(tta_filter(self.bits_per_sample, unfiltered_ch)) # run fixed order prediction on each channel predicted = [] for filtered_ch in filtered: predicted.append(fixed_predictor(self.bits_per_sample, filtered_ch)) if (self.channels == 1): # send channel as-is return from_list(predicted[0], 1, self.bits_per_sample, True) else: # decorrelate channels decorrelated = decorrelate(predicted) # return all channels as single FrameList return from_channels([ from_list(decorrelated_ch, 1, self.bits_per_sample, True) for decorrelated_ch in decorrelated ]) def close(self): # FIXME pass
def parse(cls, file_data): from io import BytesIO def tags(file, order): while True: reader = BitstreamReader(file, order) # read all the tags in an IFD tag_count = reader.read(16) sub_reader = reader.substream(tag_count * 12) next_ifd = reader.read(32) for i in range(tag_count): (tag_code, tag_datatype, tag_value_count) = sub_reader.parse("16u 16u 32u") if tag_datatype == 1: # BYTE type tag_struct = "8u" * tag_value_count elif tag_datatype == 3: # SHORT type tag_struct = "16u" * tag_value_count elif tag_datatype == 4: # LONG type tag_struct = "32u" * tag_value_count else: # all other types tag_struct = "4b" if format_size(tag_struct) <= 32: yield (tag_code, sub_reader.parse(tag_struct)) sub_reader.skip(32 - format_size(tag_struct)) else: offset = sub_reader.read(32) file.seek(offset, 0) yield (tag_code, BitstreamReader(file, order).parse(tag_struct)) if next_ifd != 0: file.seek(next_ifd, 0) else: break file = BytesIO(file_data) try: byte_order = file.read(2) if byte_order == b'II': order = 1 elif byte_order == b'MM': order = 0 else: from audiotools.text import ERR_IMAGE_INVALID_TIFF raise InvalidTIFF(ERR_IMAGE_INVALID_TIFF) reader = BitstreamReader(file, order) if reader.read(16) != 42: from audiotools.text import ERR_IMAGE_INVALID_TIFF raise InvalidTIFF(ERR_IMAGE_INVALID_TIFF) initial_ifd = reader.read(32) file.seek(initial_ifd, 0) width = 0 height = 0 bits_per_pixel = 0 color_count = 0 for (tag_id, tag_values) in tags(file, order): if tag_id == 0x0100: width = tag_values[0] elif tag_id == 0x0101: height = tag_values[0] elif tag_id == 0x0102: bits_per_pixel = sum(tag_values) elif tag_id == 0x0140: color_count = len(tag_values) // 3 except IOError: from audiotools.text import ERR_IMAGE_IOERROR_TIFF raise InvalidTIFF(ERR_IMAGE_IOERROR_TIFF) return cls(width=width, height=height, bits_per_pixel=bits_per_pixel, color_count=color_count)
class TTADecoder: def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), True) crc = CRC32() self.reader.add_callback(crc.update) #read the header (signature, format_, self.channels, self.bits_per_sample, self.sample_rate, self.total_pcm_frames) = self.reader.parse( "4b 16u 16u 16u 32u 32u") self.reader.pop_callback() header_crc = self.reader.read(32) if (int(crc) != header_crc): raise ValueError( "CRC32 mismatch in header (0x%8.8X != 0x%8.8X)" % (header_crc, int(crc))) self.channel_mask = {1:0x4, 2:0x3}.get(self.channels, 0) total_tta_frames = div_ceil(self.total_pcm_frames * 245, self.sample_rate * 256) self.pcm_frames_per_tta_frame = (self.sample_rate * 256) / 245 #read the seektable crc = CRC32() self.reader.add_callback(crc.update) self.frame_sizes = [self.reader.read(32) for i in xrange(total_tta_frames)] self.reader.pop_callback() seektable_crc = self.reader.read(32) if (int(crc) != seektable_crc): raise ValueError( "CRC32 mismatch in seektable (0x%8.8X != 0x%8.8X)" % (header_crc, int(crc))) self.current_tta_frame = 0 def read(self, pcm_frames): if (self.total_pcm_frames == 0): return FrameList("", self.channels, self.bits_per_sample, True, True) pcm_frames = min(self.pcm_frames_per_tta_frame, self.total_pcm_frames) frame_reader = self.reader.substream( self.frame_sizes[self.current_tta_frame]) crc = CRC32() frame_reader.add_callback(crc.update) self.total_pcm_frames -= pcm_frames self.current_tta_frame += 1 #setup Rice parameters for each channel k0 = [10] * self.channels k1 = [10] * self.channels sum0 = [2 ** 14] * self.channels sum1 = [2 ** 14] * self.channels #list of unfiltered output for each channel unfiltered = [[] for i in xrange(self.channels)] for f in xrange(pcm_frames): correlated = [] for (c, ch_output) in enumerate(unfiltered): #read most-significant bits MSB = frame_reader.unary(0) if (MSB == 0): #read least-significant bits unsigned = frame_reader.read(k0[c]) else: #read least-significant bits LSB = frame_reader.read(k1[c]) unshifted = ((MSB - 1) << k1[c]) + LSB unsigned = unshifted + (1 << k0[c]) #adjust sum1 and k1 sum1[c] += (unshifted - (sum1[c] >> 4)) if (sum1[c] < (2 ** (k1[c] + 4))): k1[c] = max(k1[c] - 1, 0) elif (sum1[c] > (2 ** (k1[c] + 5))): k1[c] += 1 #adjust sum0 and k0 sum0[c] += (unsigned - (sum0[c] >> 4)) if (sum0[c] < (2 ** (k0[c] + 4))): k0[c] = max(k0[c] - 1, 0) elif (sum0[c] > (2 ** (k0[c] + 5))): k0[c] += 1 #apply sign bit if ((unsigned % 2) == 1): #positive ch_output.append((unsigned + 1) / 2) else: #negative ch_output.append(-(unsigned / 2)) #check frame's trailing CRC32 now that reading is finished frame_reader.byte_align() frame_reader.pop_callback() frame_crc = frame_reader.read(32) if (int(crc) != frame_crc): raise ValueError("CRC32 mismatch in frame (0x%8.8X != 0x%8.8X)" % (frame_crc, int(crc))) #run hybrid filter on each channel filtered = [] for unfiltered_ch in unfiltered: filtered.append( tta_filter(self.bits_per_sample, unfiltered_ch)) #run fixed order prediction on each channel predicted = [] for filtered_ch in filtered: predicted.append( fixed_predictor(self.bits_per_sample, filtered_ch)) if (self.channels == 1): #send channel as-is return from_list(predicted[0], 1, self.bits_per_sample, True) else: #decorrelate channels decorrelated = decorrelate(predicted) #return all channels as single FrameList return from_channels([from_list(decorrelated_ch, 1, self.bits_per_sample, True) for decorrelated_ch in decorrelated]) def close(self): #FIXME pass
def __parse_info__(self): """generates a cache of sample_rate, bits-per-sample, etc""" import re import os.path from audiotools.bitstream import BitstreamReader if (len(self.tracks) == 0): return # Why is this post-init processing necessary? # DVDATrack references DVDATitle # so a DVDATitle must exist when DVDATrack is initialized. # But because reading this info requires knowing the sector # of the first track, we wind up with a circular dependency. # Doing a "post-process" pass fixes that problem. # find the AOB file of the title's first track track_sector = self[0].first_sector titleset = re.compile("ATS_%2.2d_\\d\\.AOB" % (self.titleset)) for aob_path in sorted([ self.dvdaudio.files[key] for key in self.dvdaudio.files.keys() if (titleset.match(key)) ]): aob_sectors = os.path.getsize(aob_path) // DVDAudio.SECTOR_SIZE if (track_sector > aob_sectors): track_sector -= aob_sectors else: break else: from audiotools.text import ERR_DVDA_NO_TRACK_SECTOR raise ValueError(ERR_DVDA_NO_TRACK_SECTOR) # open that AOB file and seek to that track's first sector aob_file = open(aob_path, 'rb') try: aob_file.seek(track_sector * DVDAudio.SECTOR_SIZE) aob_reader = BitstreamReader(aob_file, 0) # read and validate the pack header # (there's one pack header per sector, at the sector's start) (sync_bytes, marker1, current_pts_high, marker2, current_pts_mid, marker3, current_pts_low, marker4, scr_extension, marker5, bit_rate, marker6, stuffing_length) = aob_reader.parse( "32u 2u 3u 1u 15u 1u 15u 1u 9u 1u 22u 2u 5p 3u") aob_reader.skip_bytes(stuffing_length) if (sync_bytes != 0x1BA): from audiotools.text import ERR_DVDA_INVALID_AOB_SYNC raise InvalidDVDA(ERR_DVDA_INVALID_AOB_SYNC) if (((marker1 != 1) or (marker2 != 1) or (marker3 != 1) or (marker4 != 1) or (marker5 != 1) or (marker6 != 3))): from audiotools.text import ERR_DVDA_INVALID_AOB_MARKER raise InvalidDVDA(ERR_DVDA_INVALID_AOB_MARKER) packet_pts = ((current_pts_high << 30) | (current_pts_mid << 15) | current_pts_low) # skip packets until one with a stream ID of 0xBD is found (start_code, stream_id, packet_length) = aob_reader.parse("24u 8u 16u") if (start_code != 1): from audiotools.text import ERR_DVDA_INVALID_AOB_START raise InvalidDVDA(ERR_DVDA_INVALID_AOB_START) while (stream_id != 0xBD): aob_reader.skip_bytes(packet_length) (start_code, stream_id, packet_length) = aob_reader.parse("24u 8u 16u") if (start_code != 1): from audiotools.text import ERR_DVDA_INVALID_AOB_START raise InvalidDVDA(ERR_DVDA_INVALID_AOB_START) # parse the PCM/MLP header in the packet data (pad1_size, ) = aob_reader.parse("16p 8u") aob_reader.skip_bytes(pad1_size) (stream_id, crc) = aob_reader.parse("8u 8u 8p") if (stream_id == 0xA0): # PCM # read a PCM reader (pad2_size, first_audio_frame, padding2, group1_bps, group2_bps, group1_sample_rate, group2_sample_rate, padding3, channel_assignment ) = aob_reader.parse("8u 16u 8u 4u 4u 4u 4u 8u 8u") else: # MLP aob_reader.skip_bytes(aob_reader.read(8)) # skip pad2 # read a total frame size + MLP major sync header (total_frame_size, sync_words, stream_type, group1_bps, group2_bps, group1_sample_rate, group2_sample_rate, unknown1, channel_assignment, unknown2) = aob_reader.parse( "4p 12u 16p 24u 8u 4u 4u 4u 4u 11u 5u 48u") # return the values indicated by the header self.sample_rate = DVDATrack.SAMPLE_RATE[group1_sample_rate] self.channels = DVDATrack.CHANNELS[channel_assignment] self.channel_mask = DVDATrack.CHANNEL_MASK[channel_assignment] self.bits_per_sample = DVDATrack.BITS_PER_SAMPLE[group1_bps] self.stream_id = stream_id finally: aob_file.close()
class FlacDecoder(object): CHANNEL_COUNT = [ 1, 2, 3, 4, 5, 6, 7, 8, 2, 2, 2, None, None, None, None, None ] (SUBFRAME_CONSTANT, SUBFRAME_VERBATIM, SUBFRAME_FIXED, SUBFRAME_LPC) = range(4) def __init__(self, filename, channel_mask): self.reader = BitstreamReader(open(filename, "rb"), False) if (self.reader.read_bytes(4) != b'fLaC'): raise ValueError("invalid FLAC file") self.current_md5sum = md5() # locate the STREAMINFO, # which is sometimes needed to handle non-subset streams for (block_id, block_size, block_reader) in self.metadata_blocks(self.reader): if (block_id == 0): # read STREAMINFO self.minimum_block_size = block_reader.read(16) self.maximum_block_size = block_reader.read(16) self.minimum_frame_size = block_reader.read(24) self.maximum_frame_size = block_reader.read(24) self.sample_rate = block_reader.read(20) self.channels = block_reader.read(3) + 1 self.channel_mask = channel_mask self.bits_per_sample = block_reader.read(5) + 1 self.total_frames = block_reader.read(36) self.md5sum = block_reader.read_bytes(16) # these are frame header lookup tables # which vary slightly depending on STREAMINFO's values self.BLOCK_SIZE = [ self.maximum_block_size, 192, 576, 1152, 2304, 4608, None, None, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768 ] self.SAMPLE_RATE = [ self.sample_rate, 88200, 176400, 192000, 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000, None, None, None, None ] self.BITS_PER_SAMPLE = [ self.bits_per_sample, 8, 12, None, 16, 20, 24, None ] def metadata_blocks(self, reader): """yields a (block_id, block_size, block_reader) tuple per metadata block where block_reader is a BitstreamReader substream""" (last_block, block_id, block_size) = self.reader.parse("1u 7u 24u") while (last_block == 0): yield (block_id, block_size, self.reader.substream(block_size)) (last_block, block_id, block_size) = self.reader.parse("1u 7u 24u") else: yield (block_id, block_size, self.reader.substream(block_size)) def read(self, pcm_frames): # if the stream is exhausted, # verify its MD5 sum and return an empty pcm.FrameList object if (self.total_frames < 1): if (self.md5sum == self.current_md5sum.digest()): return empty_framelist(self.channels, self.bits_per_sample) else: raise ValueError("MD5 checksum mismatch") crc16 = CRC16() self.reader.add_callback(crc16.update) # fetch the decoding parameters from the frame header (block_size, channel_assignment, bits_per_sample) = self.read_frame_header() channel_count = self.CHANNEL_COUNT[channel_assignment] if (channel_count is None): raise ValueError("invalid channel assignment") # channel data will be a list of signed sample lists, one per channel # such as [[1, 2, 3, ...], [4, 5, 6, ...]] for a 2 channel stream channel_data = [] for channel_number in range(channel_count): if ((channel_assignment == 0x8) and (channel_number == 1)): # for left-difference assignment # the difference channel has 1 additional bit channel_data.append( self.read_subframe(block_size, bits_per_sample + 1)) elif ((channel_assignment == 0x9) and (channel_number == 0)): # for difference-right assignment # the difference channel has 1 additional bit channel_data.append( self.read_subframe(block_size, bits_per_sample + 1)) elif ((channel_assignment == 0xA) and (channel_number == 1)): # for average-difference assignment # the difference channel has 1 additional bit channel_data.append( self.read_subframe(block_size, bits_per_sample + 1)) else: # otherwise, use the frame's bits-per-sample value channel_data.append( self.read_subframe(block_size, bits_per_sample)) # one all the subframes have been decoded, # reconstruct them depending on the channel assignment if (channel_assignment == 0x8): # left-difference samples = [] for (left, difference) in zip(*channel_data): samples.append(left) samples.append(left - difference) elif (channel_assignment == 0x9): # difference-right samples = [] for (difference, right) in zip(*channel_data): samples.append(difference + right) samples.append(right) elif (channel_assignment == 0xA): # mid-side samples = [] for (mid, side) in zip(*channel_data): samples.append((((mid * 2) + (side % 2)) + side) // 2) samples.append((((mid * 2) + (side % 2)) - side) // 2) else: # independent samples = [0] * block_size * channel_count for (i, channel) in enumerate(channel_data): samples[i::channel_count] = channel self.reader.byte_align() # read and verify the frame's trailing CRC-16 footer self.reader.read(16) self.reader.pop_callback() if (int(crc16) != 0): raise ValueError("CRC16 mismatch in frame footer") # deduct the amount of PCM frames from the remaining amount self.total_frames -= block_size # build a pcm.FrameList object from the combined samples framelist = from_list(samples, channel_count, bits_per_sample, True) # update the running MD5 sum calculation with the frame's data self.current_md5sum.update(framelist.to_bytes(0, 1)) # and finally return the frame data return framelist def read_frame_header(self): crc8 = CRC8() self.reader.add_callback(crc8.update) # read the 32-bit FLAC frame header sync_code = self.reader.read(14) if (sync_code != 0x3FFE): raise ValueError("invalid sync code") self.reader.skip(1) blocking_strategy = self.reader.read(1) block_size_bits = self.reader.read(4) sample_rate_bits = self.reader.read(4) channel_assignment = self.reader.read(4) bits_per_sample_bits = self.reader.read(3) self.reader.skip(1) # the frame number is a UTF-8 encoded value # which takes a variable number of whole bytes frame_number = self.read_utf8() # unpack the 4 bit block size field # which is the total PCM frames in the FLAC frame # and may require up to 16 more bits if the frame is usually-sized # (which typically happens at the end of the stream) if (block_size_bits == 0x6): block_size = self.reader.read(8) + 1 elif (block_size_bits == 0x7): block_size = self.reader.read(16) + 1 else: block_size = self.BLOCK_SIZE[block_size_bits] # unpack the 4 bit sample rate field # which is used for playback, but not needed for decoding # and may require up to 16 more bits # if the stream has a particularly unusual sample rate if (sample_rate_bits == 0xC): sample_rate = self.reader.read(8) * 1000 elif (sample_rate_bits == 0xD): sample_rate = self.reader.read(16) elif (sample_rate_bits == 0xE): sample_rate = self.reader.read(16) * 10 elif (sample_rate_bits == 0xF): raise ValueError("invalid sample rate") else: sample_rate = self.SAMPLE_RATE[sample_rate_bits] # unpack the 3 bit bits-per-sample field # this never requires additional bits if ((bits_per_sample_bits == 0x3) or (bits_per_sample_bits == 0x7)): raise ValueError("invalid bits per sample") else: bits_per_sample = self.BITS_PER_SAMPLE[bits_per_sample_bits] # read and verify frame's CRC-8 value self.reader.read(8) self.reader.pop_callback() if (int(crc8) != 0): raise ValueError("CRC8 mismatch in frame header") return (block_size, channel_assignment, bits_per_sample) def read_subframe_header(self): """returns a tuple of (subframe_type, subframe_order, wasted_bps)""" self.reader.skip(1) subframe_type = self.reader.read(6) if (self.reader.read(1) == 1): wasted_bps = self.reader.unary(1) + 1 else: wasted_bps = 0 # extract "order" value from 6 bit subframe type, if necessary if (subframe_type == 0): return (self.SUBFRAME_CONSTANT, None, wasted_bps) elif (subframe_type == 1): return (self.SUBFRAME_VERBATIM, None, wasted_bps) elif ((subframe_type & 0x38) == 0x08): return (self.SUBFRAME_FIXED, subframe_type & 0x07, wasted_bps) elif ((subframe_type & 0x20) == 0x20): return (self.SUBFRAME_LPC, (subframe_type & 0x1F) + 1, wasted_bps) else: raise ValueError("invalid subframe type") def read_subframe(self, block_size, bits_per_sample): (subframe_type, subframe_order, wasted_bps) = self.read_subframe_header() # read a list of signed sample values # depending on the subframe type, block size, # adjusted bits per sample and optional subframe order if (subframe_type == self.SUBFRAME_CONSTANT): subframe_samples = self.read_constant_subframe( block_size, bits_per_sample - wasted_bps) elif (subframe_type == self.SUBFRAME_VERBATIM): subframe_samples = self.read_verbatim_subframe( block_size, bits_per_sample - wasted_bps) elif (subframe_type == self.SUBFRAME_FIXED): subframe_samples = self.read_fixed_subframe( block_size, bits_per_sample - wasted_bps, subframe_order) else: subframe_samples = self.read_lpc_subframe( block_size, bits_per_sample - wasted_bps, subframe_order) # account for wasted bits-per-sample, if necessary if (wasted_bps): return [sample << wasted_bps for sample in subframe_samples] else: return subframe_samples def read_constant_subframe(self, block_size, bits_per_sample): sample = self.reader.read_signed(bits_per_sample) return [sample] * block_size def read_verbatim_subframe(self, block_size, bits_per_sample): return [ self.reader.read_signed(bits_per_sample) for x in range(block_size) ] def read_fixed_subframe(self, block_size, bits_per_sample, order): # "order" number of warm-up samples samples = [ self.reader.read_signed(bits_per_sample) for i in range(order) ] # "block_size" - "order" number of residual values residuals = self.read_residual(block_size, order) # which are applied to the warm-up samples # depending on the FIXED subframe order # and results in "block_size" number of total samples if (order == 0): return residuals elif (order == 1): for residual in residuals: samples.append(samples[-1] + residual) return samples elif (order == 2): for residual in residuals: samples.append((2 * samples[-1]) - samples[-2] + residual) return samples elif (order == 3): for residual in residuals: samples.append((3 * samples[-1]) - (3 * samples[-2]) + samples[-3] + residual) return samples elif (order == 4): for residual in residuals: samples.append((4 * samples[-1]) - (6 * samples[-2]) + (4 * samples[-3]) - samples[-4] + residual) return samples else: raise ValueError("unsupported FIXED subframe order") def read_lpc_subframe(self, block_size, bits_per_sample, order): # "order" number of warm-up samples samples = [ self.reader.read_signed(bits_per_sample) for i in range(order) ] # the size of each QLP coefficient, in bits qlp_precision = self.reader.read(4) # the amount of right shift to apply # during LPC calculation # (though this is a signed value, negative shifts are noops # in the reference FLAC decoder) qlp_shift_needed = max(self.reader.read_signed(5), 0) # "order" number of signed QLP coefficients qlp_coeffs = [ self.reader.read_signed(qlp_precision + 1) for i in range(order) ] # QLP coefficients are applied in reverse order qlp_coeffs.reverse() # "block_size" - "order" number of residual values residuals = self.read_residual(block_size, order) # which are applied to the running LPC calculation for residual in residuals: samples.append((sum([ coeff * sample for (coeff, sample) in zip(qlp_coeffs, samples[-order:]) ]) >> qlp_shift_needed) + residual) return samples def read_residual(self, block_size, order): residuals = [] coding_method = self.reader.read(2) partition_order = self.reader.read(4) # each parititon contains block_size / 2 ** partition_order # number of residuals for partition_number in range(2**partition_order): if (partition_number == 0): # except for the first partition # which contains "order" less than the rest residuals.extend( self.read_residual_partition( coding_method, (block_size // 2**partition_order) - order)) else: residuals.extend( self.read_residual_partition( coding_method, block_size // 2**partition_order)) return residuals def read_residual_partition(self, coding_method, residual_count): if (coding_method == 0): # the Rice parameters determines the number of # least-significant bits to read for each residual rice_parameter = self.reader.read(4) if (rice_parameter == 0xF): escape_code = self.reader.read(5) return [ self.reader.read_signed(escape_code) for i in range(residual_count) ] elif (coding_method == 1): # 24 bps streams may use a 5-bit Rice parameter # for better compression rice_parameter = self.reader.read(5) if (rice_parameter == 0x1F): escape_code = self.reader.read(5) return [ self.reader.read_signed(escape_code) for i in range(residual_count) ] else: raise ValueError("invalid Rice coding parameter") # a list of signed residual values partition_residuals = [] for i in range(residual_count): msb = self.reader.unary(1) # most-significant bits lsb = self.reader.read(rice_parameter) # least-significant bits value = (msb << rice_parameter) | lsb # combined into a value if (value & 1): # whose least-significant bit is the sign value partition_residuals.append(-(value >> 1) - 1) else: partition_residuals.append(value >> 1) return partition_residuals def read_utf8(self): total_bytes = self.reader.unary(0) value = self.reader.read(7 - total_bytes) while (total_bytes > 1): value = ((value << 6) | self.reader.parse("2p 6u")[0]) total_bytes -= 1 return value def close(self): self.reader.close() def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close()
def __init__(self, filename): """filename is a plain string""" AudioFile.__init__(self, filename) self.__channels__ = 0 self.__channel_mask__ = 0 #get channel count and channel mask from first packet from .bitstream import BitstreamReader try: f = open(filename, "rb") try: ogg_reader = BitstreamReader(f, 1) (magic_number, version, header_type, granule_position, self.__serial_number__, page_sequence_number, checksum, segment_count) = ogg_reader.parse( "4b 8u 8u 64S 32u 32u 32u 8u") if (magic_number != 'OggS'): from .text import ERR_OGG_INVALID_MAGIC_NUMBER raise InvalidFLAC(ERR_OGG_INVALID_MAGIC_NUMBER) if (version != 0): from .text import ERR_OGG_INVALID_VERSION raise InvalidFLAC(ERR_OGG_INVALID_VERSION) segment_length = ogg_reader.read(8) (opushead, version, self.__channels__, pre_skip, input_sample_rate, output_gain, mapping_family) = ogg_reader.parse( "8b 8u 8u 16u 32u 16s 8u") if (opushead != "OpusHead"): from .text import ERR_OPUS_INVALID_TYPE raise InvalidOpus(ERR_OPUS_INVALID_TYPE) if (version != 1): from .text import ERR_OPUS_INVALID_VERSION raise InvalidOpus(ERR_OPUS_INVALID_VERSION) if (self.__channels__ == 0): from .text import ERR_OPUS_INVALID_CHANNELS raise InvalidOpus(ERR_OPUS_INVALID_CHANNELS) #FIXME - assign channel mask from mapping family if (mapping_family == 0): if (self.__channels__ == 1): self.__channel_mask__ = VorbisChannelMask(0x4) elif (self.__channels__ == 2): self.__channel_mask__ = VorbisChannelMask(0x3) else: self.__channel_mask__ = VorbisChannelMask(0) else: (stream_count, coupled_stream_count) = ogg_reader.parse("8u 8u") if (self.__channels__ != ((coupled_stream_count * 2) + (stream_count - coupled_stream_count))): from .text import ERR_OPUS_INVALID_CHANNELS raise InvalidOpus(ERR_OPUS_INVALID_CHANNELS) channel_mapping = [ogg_reader.read(8) for i in xrange(self.__channels__)] finally: f.close() except IOError, msg: raise InvalidOpus(str(msg))
class SHNDecoder(object): def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), False) (self.file_type, self.channels, self.block_length, self.max_LPC, self.number_of_means) = self.read_header() if (1 <= self.file_type) and (self.file_type <= 2): self.bits_per_sample = 8 self.signed_samples = (self.file_type == 1) elif (3 <= self.file_type) and (self.file_type <= 6): self.bits_per_sample = 16 self.signed_samples = (self.file_type in (3, 5)) else: raise ValueError("unsupported Shorten file type") self.wrapped_samples = [[0] * 3 for c in range(self.channels)] self.means = [[0] * self.number_of_means for c in range(self.channels)] self.left_shift = 0 self.stream_finished = False # try to read the first command for a wave/aiff header data_start = self.reader.getpos() self.read_metadata() self.reader.setpos(data_start) def read_metadata(self): from io import BytesIO command = self.unsigned(2) if command == 9: # got verbatim, so read data verbatim_bytes = ints_to_bytes([self.unsigned(8) & 0xFF for i in range(self.unsigned(5))]) try: wave = BitstreamReader(BytesIO(verbatim_bytes), True) header = wave.read_bytes(12) if header.startswith(b"RIFF") and header.endswith(b"WAVE"): # got RIFF/WAVE header, so parse wave blocks as needed total_size = len(verbatim_bytes) - 12 while total_size > 0: (chunk_id, chunk_size) = wave.parse("4b 32u") total_size -= 8 if chunk_id == b'fmt ': (channels, self.sample_rate, bits_per_sample, channel_mask) = parse_fmt( wave.substream(chunk_size)) self.channel_mask = int(channel_mask) return else: if chunk_size % 2: wave.read_bytes(chunk_size + 1) total_size -= (chunk_size + 1) else: wave.read_bytes(chunk_size) total_size -= chunk_size else: # no fmt chunk, so use default metadata pass except (IOError, ValueError): pass try: aiff = BitstreamReader(BytesIO(verbatim_bytes), False) header = aiff.read_bytes(12) if header.startswith(b"FORM") and header.endswith(b"AIFF"): # got FORM/AIFF header, so parse aiff blocks as needed total_size = len(verbatim_bytes) - 12 while total_size > 0: (chunk_id, chunk_size) = aiff.parse("4b 32u") total_size -= 8 if chunk_id == b'COMM': (channels, total_sample_frames, bits_per_sample, self.sample_rate, channel_mask) = parse_comm( aiff.substream(chunk_size)) self.channel_mask = int(channel_mask) return else: if chunk_size % 2: aiff.read_bytes(chunk_size + 1) total_size -= (chunk_size + 1) else: aiff.read_bytes(chunk_size) total_size -= chunk_size else: # no COMM chunk, so use default metadata pass except IOError: pass # got something else, so invent some PCM parameters self.sample_rate = 44100 if self.channels == 1: self.channel_mask = 0x4 elif self.channels == 2: self.channel_mask = 0x3 else: self.channel_mask = 0 def unsigned(self, c): MSB = self.reader.unary(1) LSB = self.reader.read(c) return MSB * 2 ** c + LSB def signed(self, c): u = self.unsigned(c + 1) if (u % 2) == 0: return u // 2 else: return -(u // 2) - 1 def long(self): return self.unsigned(self.unsigned(2)) def skip_unsigned(self, c): self.reader.skip_unary(1) self.reader.skip(c) def read_header(self): magic = self.reader.read_bytes(4) if magic != b"ajkg": raise ValueError("invalid magic number") version = self.reader.read(8) if version != 2: raise ValueError("unsupported version") file_type = self.long() channels = self.long() block_length = self.long() max_LPC = self.long() number_of_means = self.long() bytes_to_skip = self.long() self.reader.read_bytes(bytes_to_skip) return (file_type, channels, block_length, max_LPC, number_of_means) def read(self, pcm_frames): if self.stream_finished: return from_channels([empty_framelist(1, self.bits_per_sample) for channel in range(self.channels)]) c = 0 samples = [] unshifted = [] while True: command = self.unsigned(2) if (((0 <= command) and (command <= 3) or (7 <= command) and (command <= 8))): # audio data commands if command == 0: # DIFF0 samples.append(self.read_diff0(self.block_length, self.means[c])) elif command == 1: # DIFF1 samples.append(self.read_diff1(self.block_length, self.wrapped_samples[c])) elif command == 2: # DIFF2 samples.append(self.read_diff2(self.block_length, self.wrapped_samples[c])) elif command == 3: # DIFF3 samples.append(self.read_diff3(self.block_length, self.wrapped_samples[c])) elif command == 7: # QLPC samples.append(self.read_qlpc(self.block_length, self.means[c], self.wrapped_samples[c])) elif command == 8: # ZERO samples.append([0] * self.block_length) # update means for channel self.means[c].append(shnmean(samples[c])) self.means[c] = self.means[c][1:] # wrap samples for next command in channel self.wrapped_samples[c] = samples[c][-(max(3, self.max_LPC)):] # apply left shift to samples if self.left_shift > 0: unshifted.append([s << self.left_shift for s in samples[c]]) else: unshifted.append(samples[c]) c += 1 if c == self.channels: # return a FrameList from shifted data return from_channels([from_list(channel, 1, self.bits_per_sample, self.signed_samples) for channel in unshifted]) else: # non audio commands if command == 4: # QUIT self.stream_finished = True return from_channels( [empty_framelist(1, self.bits_per_sample) for channel in range(self.channels)]) elif command == 5: # BLOCKSIZE self.block_length = self.long() elif command == 6: # BITSHIFT self.left_shift = self.unsigned(2) elif command == 9: # VERBATIM # skip this command during reading size = self.unsigned(5) for i in range(size): self.skip_unsigned(8) else: raise ValueError("unsupported Shorten command") def read_diff0(self, block_length, means): offset = shnmean(means) energy = self.unsigned(3) samples = [] for i in range(block_length): residual = self.signed(energy) samples.append(residual + offset) return samples def read_diff1(self, block_length, previous_samples): samples = previous_samples[-1:] energy = self.unsigned(3) for i in range(1, block_length + 1): residual = self.signed(energy) samples.append(samples[i - 1] + residual) return samples[1:] def read_diff2(self, block_length, previous_samples): samples = previous_samples[-2:] energy = self.unsigned(3) for i in range(2, block_length + 2): residual = self.signed(energy) samples.append((2 * samples[i - 1]) - samples[i - 2] + residual) return samples[2:] def read_diff3(self, block_length, previous_samples): samples = previous_samples[-3:] energy = self.unsigned(3) for i in range(3, block_length + 3): residual = self.signed(energy) samples.append((3 * (samples[i - 1] - samples[i - 2])) + samples[i - 3] + residual) return samples[3:] def read_qlpc(self, block_length, means, previous_samples): offset = shnmean(means) energy = self.unsigned(3) LPC_count = self.unsigned(2) LPC_coeff = [self.signed(5) for i in range(LPC_count)] unoffset = [] samples = previous_samples[-LPC_count:] for i in range(block_length): residual = self.signed(energy) LPC_sum = 2 ** 5 for j in range(LPC_count): if (i - j - 1) < 0: # apply offset to warm-up samples LPC_sum += (LPC_coeff[j] * (samples[LPC_count + (i - j - 1)] - offset)) else: LPC_sum += LPC_coeff[j] * unoffset[i - j - 1] unoffset.append(LPC_sum // 2 ** 5 + residual) return [u + offset for u in unoffset] def close(self): self.reader.close() def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close()
def __init__(self, filename): """filename is a plain string""" AudioFile.__init__(self, filename) self.__channels__ = 0 self.__channel_mask__ = 0 # get channel count and channel mask from first packet from audiotools.bitstream import BitstreamReader try: f = open(filename, "rb") try: ogg_reader = BitstreamReader(f, 1) (magic_number, version, header_type, granule_position, self.__serial_number__, page_sequence_number, checksum, segment_count ) = ogg_reader.parse("4b 8u 8u 64S 32u 32u 32u 8u") if (magic_number != 'OggS'): from audiotools.text import ERR_OGG_INVALID_MAGIC_NUMBER raise InvalidOpus(ERR_OGG_INVALID_MAGIC_NUMBER) if (version != 0): from audiotools.text import ERR_OGG_INVALID_VERSION raise InvalidOpus(ERR_OGG_INVALID_VERSION) segment_length = ogg_reader.read(8) (opushead, version, self.__channels__, pre_skip, input_sample_rate, output_gain, mapping_family) = ogg_reader.parse("8b 8u 8u 16u 32u 16s 8u") if (opushead != "OpusHead"): from audiotools.text import ERR_OPUS_INVALID_TYPE raise InvalidOpus(ERR_OPUS_INVALID_TYPE) if (version != 1): from audiotools.text import ERR_OPUS_INVALID_VERSION raise InvalidOpus(ERR_OPUS_INVALID_VERSION) if (self.__channels__ == 0): from audiotools.text import ERR_OPUS_INVALID_CHANNELS raise InvalidOpus(ERR_OPUS_INVALID_CHANNELS) # FIXME - assign channel mask from mapping family if (mapping_family == 0): if (self.__channels__ == 1): self.__channel_mask__ = VorbisChannelMask(0x4) elif (self.__channels__ == 2): self.__channel_mask__ = VorbisChannelMask(0x3) else: self.__channel_mask__ = VorbisChannelMask(0) else: (stream_count, coupled_stream_count) = ogg_reader.parse("8u 8u") if (self.__channels__ != ((coupled_stream_count * 2) + (stream_count - coupled_stream_count))): from audiotools.text import ERR_OPUS_INVALID_CHANNELS raise InvalidOpus(ERR_OPUS_INVALID_CHANNELS) channel_mapping = [ ogg_reader.read(8) for i in range(self.__channels__) ] finally: f.close() except IOError as msg: raise InvalidOpus(str(msg))
class SHNDecoder(object): def __init__(self, filename): self.reader = BitstreamReader(open(filename, "rb"), False) (self.file_type, self.channels, self.block_length, self.max_LPC, self.number_of_means) = self.read_header() if ((1 <= self.file_type) and (self.file_type <= 2)): self.bits_per_sample = 8 self.signed_samples = (self.file_type == 1) elif ((3 <= self.file_type) and (self.file_type <= 6)): self.bits_per_sample = 16 self.signed_samples = (self.file_type in (3, 5)) else: raise ValueError("unsupported Shorten file type") self.wrapped_samples = [[0] * 3 for c in range(self.channels)] self.means = [[0] * self.number_of_means for c in range(self.channels)] self.left_shift = 0 self.stream_finished = False # try to read the first command for a wave/aiff header self.reader.mark() self.read_metadata() self.reader.rewind() self.reader.unmark() def read_metadata(self): from io import BytesIO command = self.unsigned(2) if (command == 9): # got verbatim, so read data verbatim_bytes = ints_to_bytes( [self.unsigned(8) & 0xFF for i in range(self.unsigned(5))]) try: wave = BitstreamReader(BytesIO(verbatim_bytes), True) header = wave.read_bytes(12) if (header.startswith(b"RIFF") and header.endswith(b"WAVE")): # got RIFF/WAVE header, so parse wave blocks as needed total_size = len(verbatim_bytes) - 12 while (total_size > 0): (chunk_id, chunk_size) = wave.parse("4b 32u") total_size -= 8 if (chunk_id == b'fmt '): (channels, self.sample_rate, bits_per_sample, channel_mask) = parse_fmt( wave.substream(chunk_size)) self.channel_mask = int(channel_mask) return else: if (chunk_size % 2): wave.read_bytes(chunk_size + 1) total_size -= (chunk_size + 1) else: wave.read_bytes(chunk_size) total_size -= chunk_size else: # no fmt chunk, so use default metadata pass except (IOError, ValueError): pass try: aiff = BitstreamReader(BytesIO(verbatim_bytes), False) header = aiff.read_bytes(12) if (header.startswith(b"FORM") and header.endswith(b"AIFF")): # got FORM/AIFF header, so parse aiff blocks as needed total_size = len(verbatim_bytes) - 12 while (total_size > 0): (chunk_id, chunk_size) = aiff.parse("4b 32u") total_size -= 8 if (chunk_id == b'COMM'): (channels, total_sample_frames, bits_per_sample, self.sample_rate, channel_mask) = parse_comm( aiff.substream(chunk_size)) self.channel_mask = int(channel_mask) return else: if (chunk_size % 2): aiff.read_bytes(chunk_size + 1) total_size -= (chunk_size + 1) else: aiff.read_bytes(chunk_size) total_size -= chunk_size else: # no COMM chunk, so use default metadata pass except IOError: pass # got something else, so invent some PCM parameters self.sample_rate = 44100 if (self.channels == 1): self.channel_mask = 0x4 elif (self.channels == 2): self.channel_mask = 0x3 else: self.channel_mask = 0 def unsigned(self, c): MSB = self.reader.unary(1) LSB = self.reader.read(c) return MSB * 2**c + LSB def signed(self, c): u = self.unsigned(c + 1) if ((u % 2) == 0): return u // 2 else: return -(u // 2) - 1 def long(self): return self.unsigned(self.unsigned(2)) def skip_unsigned(self, c): self.reader.skip_unary(1) self.reader.skip(c) def read_header(self): magic = self.reader.read_bytes(4) if (magic != b"ajkg"): raise ValueError("invalid magic number") version = self.reader.read(8) if (version != 2): raise ValueError("unsupported version") file_type = self.long() channels = self.long() block_length = self.long() max_LPC = self.long() number_of_means = self.long() bytes_to_skip = self.long() self.reader.read_bytes(bytes_to_skip) return (file_type, channels, block_length, max_LPC, number_of_means) def read(self, pcm_frames): if (self.stream_finished): return from_channels([ empty_framelist(1, self.bits_per_sample) for channel in range(self.channels) ]) c = 0 samples = [] unshifted = [] while (True): command = self.unsigned(2) if (((0 <= command) and (command <= 3) or (7 <= command) and (command <= 8))): # audio data commands if (command == 0): # DIFF0 samples.append( self.read_diff0(self.block_length, self.means[c])) elif (command == 1): # DIFF1 samples.append( self.read_diff1(self.block_length, self.wrapped_samples[c])) elif (command == 2): # DIFF2 samples.append( self.read_diff2(self.block_length, self.wrapped_samples[c])) elif (command == 3): # DIFF3 samples.append( self.read_diff3(self.block_length, self.wrapped_samples[c])) elif (command == 7): # QLPC samples.append( self.read_qlpc(self.block_length, self.means[c], self.wrapped_samples[c])) elif (command == 8): # ZERO samples.append([0] * self.block_length) # update means for channel self.means[c].append(shnmean(samples[c])) self.means[c] = self.means[c][1:] # wrap samples for next command in channel self.wrapped_samples[c] = samples[c][-(max(3, self.max_LPC)):] # apply left shift to samples if (self.left_shift > 0): unshifted.append( [s << self.left_shift for s in samples[c]]) else: unshifted.append(samples[c]) c += 1 if (c == self.channels): # return a FrameList from shifted data return from_channels([ from_list(channel, 1, self.bits_per_sample, self.signed_samples) for channel in unshifted ]) else: # non audio commands if (command == 4): # QUIT self.stream_finished = True return from_channels([ empty_framelist(1, self.bits_per_sample) for channel in range(self.channels) ]) elif (command == 5): # BLOCKSIZE self.block_length = self.long() elif (command == 6): # BITSHIFT self.left_shift = self.unsigned(2) elif (command == 9): # VERBATIM # skip this command during reading size = self.unsigned(5) for i in range(size): self.skip_unsigned(8) else: raise ValueError("unsupported Shorten command") def read_diff0(self, block_length, means): offset = shnmean(means) energy = self.unsigned(3) samples = [] for i in range(block_length): residual = self.signed(energy) samples.append(residual + offset) return samples def read_diff1(self, block_length, previous_samples): samples = previous_samples[-1:] energy = self.unsigned(3) for i in range(1, block_length + 1): residual = self.signed(energy) samples.append(samples[i - 1] + residual) return samples[1:] def read_diff2(self, block_length, previous_samples): samples = previous_samples[-2:] energy = self.unsigned(3) for i in range(2, block_length + 2): residual = self.signed(energy) samples.append((2 * samples[i - 1]) - samples[i - 2] + residual) return samples[2:] def read_diff3(self, block_length, previous_samples): samples = previous_samples[-3:] energy = self.unsigned(3) for i in range(3, block_length + 3): residual = self.signed(energy) samples.append((3 * (samples[i - 1] - samples[i - 2])) + samples[i - 3] + residual) return samples[3:] def read_qlpc(self, block_length, means, previous_samples): offset = shnmean(means) energy = self.unsigned(3) LPC_count = self.unsigned(2) LPC_coeff = [self.signed(5) for i in range(LPC_count)] unoffset = [] samples = previous_samples[-LPC_count:] for i in range(block_length): residual = self.signed(energy) LPC_sum = 2**5 for j in range(LPC_count): if ((i - j - 1) < 0): # apply offset to warm-up samples LPC_sum += (LPC_coeff[j] * (samples[LPC_count + (i - j - 1)] - offset)) else: LPC_sum += LPC_coeff[j] * unoffset[i - j - 1] unoffset.append(LPC_sum // 2**5 + residual) return [u + offset for u in unoffset] def close(self): self.reader.close() def __enter__(self): return self def __exit__(self, exc_type, exc_value, traceback): self.close()