def encode_flac(filename, pcmreader,
block_size=4096,
max_lpc_order=8,
adaptive_mid_side=False,
mid_side=True,
exhaustive_model_search=False,
max_residual_partition_order=5):
options = Encoding_Options(block_size,
max_lpc_order,
adaptive_mid_side,
mid_side,
exhaustive_model_search,
max_residual_partition_order,
14 if pcmreader.bits_per_sample <= 16 else 30)
streaminfo = STREAMINFO(block_size, block_size,
2 ** 32, 0,
pcmreader.sample_rate,
pcmreader.channels,
pcmreader.bits_per_sample,
0, md5())
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, 0)
#write placeholder metadata blocks
writer.write_bytes("fLaC")
writer.build("1u 7u 24u", [1, 0, 34])
streaminfo.write(writer)
#walk through PCM reader's FrameLists
frame_number = 0
frame = pcmreader.read(block_size *
(pcmreader.bits_per_sample / 8) *
pcmreader.channels)
flac_frame = BitstreamRecorder(0)
while (len(frame) > 0):
streaminfo.input_update(frame)
flac_frame.reset()
encode_flac_frame(flac_frame, pcmreader, options, frame_number, frame)
streaminfo.output_update(flac_frame)
flac_frame.copy(writer)
frame_number += 1
frame = pcmreader.read(block_size *
(pcmreader.bits_per_sample / 8) *
pcmreader.channels)
#return to beginning of file and rewrite STREAMINFO block
output_file.seek(8, 0)
streaminfo.write(writer)
writer.close()
def set_replay_gain(self, replaygain):
"""given a ReplayGain object, sets the track's gain to those values
may raise IOError if unable to modify the file"""
from math import log10
from audiotools import TemporaryFile
gain_title = int(round((64.82 - replaygain.track_gain) * 256))
if replaygain.track_peak > 0.0:
peak_title = int(log10(replaygain.track_peak * 2 ** 15) * 20 * 256)
else:
peak_title = 0
gain_album = int(round((64.82 - replaygain.album_gain) * 256))
if replaygain.album_peak > 0.0:
peak_album = int(log10(replaygain.album_peak * 2 ** 15) * 20 * 256)
else:
peak_album = 0
#FIXME - check for missing "RG" block and add one if not present
metadata = self.get_metadata()
writer = BitstreamWriter(TemporaryFile(self.filename), False)
writer.write_bytes(b"MPCK")
for key, size, block in self.blocks():
if key != b"RG":
writer.write_bytes(key)
size.build(writer)
writer.write_bytes(block)
else:
writer.write_bytes(b"RG")
MPC_Size(2 + 1 + 1 + 2 * 4, 1).build(writer)
writer.write(8, 1)
writer.write(16, gain_title)
writer.write(16, peak_title)
writer.write(16, gain_album)
writer.write(16, peak_album)
if metadata is not None:
writer.set_endianness(True)
metadata.build(writer)
writer.close()
def set_replay_gain(self, replaygain):
"""given a ReplayGain object, sets the track's gain to those values
may raise IOError if unable to modify the file"""
from math import log10
from audiotools import TemporaryFile
gain_title = int(round((64.82 - replaygain.track_gain) * 256))
if replaygain.track_peak > 0.0:
peak_title = int(log10(replaygain.track_peak * 2**15) * 20 * 256)
else:
peak_title = 0
gain_album = int(round((64.82 - replaygain.album_gain) * 256))
if replaygain.album_peak > 0.0:
peak_album = int(log10(replaygain.album_peak * 2**15) * 20 * 256)
else:
peak_album = 0
#FIXME - check for missing "RG" block and add one if not present
metadata = self.get_metadata()
writer = BitstreamWriter(TemporaryFile(self.filename), False)
writer.write_bytes(b"MPCK")
for key, size, block in self.blocks():
if key != b"RG":
writer.write_bytes(key)
size.build(writer)
writer.write_bytes(block)
else:
writer.write_bytes(b"RG")
MPC_Size(2 + 1 + 1 + 2 * 4, 1).build(writer)
writer.write(8, 1)
writer.write(16, gain_title)
writer.write(16, peak_title)
writer.write(16, gain_album)
writer.write(16, peak_album)
if metadata is not None:
writer.set_endianness(True)
metadata.build(writer)
writer.close()
def delete_replay_gain(self):
"""removes ReplayGain values from file, if any
may raise IOError if unable to modify the file"""
from audiotools import TemporaryFile
writer = BitstreamWriter(TemporaryFile(self.filename), False)
writer.write_bytes(b"MPCK")
for key, size, block in self.blocks():
if key != b"RG":
writer.write_bytes(key)
size.build(writer)
writer.write_bytes(block)
else:
writer.write_bytes(b"RG")
MPC_Size(2 + 1 + 1 + 2 * 4, 1).build(writer)
writer.write(8, 1)
writer.write(16, 0)
writer.write(16, 0)
writer.write(16, 0)
writer.write(16, 0)
writer.close()
def delete_replay_gain(self):
"""removes ReplayGain values from file, if any
may raise IOError if unable to modify the file"""
from audiotools import TemporaryFile
writer = BitstreamWriter(TemporaryFile(self.filename), False)
writer.write_bytes(b"MPCK")
for key, size, block in self.blocks():
if key != b"RG":
writer.write_bytes(key)
size.build(writer)
writer.write_bytes(block)
else:
writer.write_bytes(b"RG")
MPC_Size(2 + 1 + 1 + 2 * 4, 1).build(writer)
writer.write(8, 1)
writer.write(16, 0)
writer.write(16, 0)
writer.write(16, 0)
writer.write(16, 0)
writer.close()
def from_pcm(cls, filename, pcmreader,
compression=None,
total_pcm_frames=None,
encoding_function=None):
"""encodes a new file from PCM data
takes a filename string, PCMReader object,
optional compression level string and
optional total_pcm_frames integer
encodes a new audio file from pcmreader's data
at the given filename with the specified compression level
and returns a new AudioFile-compatible object
may raise EncodingError if some problem occurs when
encoding the input file. This includes an error
in the input stream, a problem writing the output file,
or even an EncodingError subclass such as
"UnsupportedBitsPerSample" if the input stream
is formatted in a way this class is unable to support
"""
from audiotools import (BufferedPCMReader,
CounterPCMReader,
transfer_data,
EncodingError)
# from audiotools.py_encoders import encode_tta
from audiotools.encoders import encode_tta
from audiotools.bitstream import BitstreamWriter
# open output file right away
# so we can fail as soon as possible
try:
file = open(filename, "wb")
except IOError as err:
pcmreader.close()
raise EncodingError(str(err))
writer = BitstreamWriter(file, True)
counter = CounterPCMReader(pcmreader)
try:
if (total_pcm_frames is not None):
# write header to disk
write_header(writer,
pcmreader.channels,
pcmreader.bits_per_sample,
pcmreader.sample_rate,
total_pcm_frames)
block_size = (pcmreader.sample_rate * 256) // 245
total_tta_frames = div_ceil(total_pcm_frames, block_size)
# write temporary seektable to disk
writer.mark()
write_seektable(writer, [0] * total_tta_frames)
writer.flush()
# write frames to disk
try:
frame_sizes = \
(encode_tta if encoding_function is None
else encoding_function)(file,
BufferedPCMReader(counter))
except (IOError, ValueError) as err:
cls.__unlink__(filename)
raise EncodingError(str(err))
# ensure written number of PCM frames
# matches total_pcm_frames
if (counter.frames_written != total_pcm_frames):
from audiotools.text import ERR_TOTAL_PCM_FRAMES_MISMATCH
cls.__unlink__(filename)
raise EncodingError(ERR_TOTAL_PCM_FRAMES_MISMATCH)
assert(len(frame_sizes) == total_tta_frames)
# go back and rewrite seektable with completed one
writer.rewind()
write_seektable(writer, frame_sizes)
writer.unmark()
else:
import tempfile
frames = tempfile.TemporaryFile()
# encode TTA frames to temporary file
try:
frame_sizes = \
(encode_tta if encoding_function is None
else encoding_function)(frames,
BufferedPCMReader(counter))
except (IOError, ValueError) as err:
frames.close()
cls.__unlink__(filename)
raise EncodingError(str(err))
# write header to disk
write_header(writer,
pcmreader.channels,
pcmreader.bits_per_sample,
pcmreader.sample_rate,
counter.frames_written)
# write seektable to disk
write_seektable(writer, frame_sizes)
# transfer TTA frames from temporary space to disk
frames.seek(0, 0)
transfer_data(frames.read, writer.write_bytes)
frames.close()
finally:
counter.close()
if (writer.has_mark()):
writer.unmark()
writer.close()
return cls(filename)
def encode_flac(filename,
pcmreader,
block_size=4096,
max_lpc_order=8,
min_residual_partition_order=0,
max_residual_partition_order=5,
mid_side=True,
adaptive_mid_side=False,
exhaustive_model_search=False,
disable_verbatim_subframes=False,
disable_constant_subframes=False,
disable_fixed_subframes=False,
disable_lpc_subframes=False,
padding_size=4096):
frame_sizes = []
options = Encoding_Options(block_size, max_lpc_order, adaptive_mid_side,
mid_side, exhaustive_model_search,
max_residual_partition_order,
14 if pcmreader.bits_per_sample <= 16 else 30)
streaminfo = STREAMINFO(block_size, block_size, (2**24) - 1, 0,
pcmreader.sample_rate, pcmreader.channels,
pcmreader.bits_per_sample, 0, md5())
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, False)
# write placeholder metadata blocks such as STREAMINFO and PADDING
writer.write_bytes("fLaC")
writer.build("1u 7u 24u", [0, 0, 34])
streaminfo_start = writer.getpos()
streaminfo.write(writer)
writer.build("1u 7u 24u", [1, 1, padding_size])
writer.write_bytes(b"\x00" * padding_size)
# walk through PCM reader's FrameLists
frame_number = 0
frame = pcmreader.read(block_size)
flac_frame = BitstreamRecorder(0)
while len(frame) > 0:
streaminfo.input_update(frame)
flac_frame.reset()
encode_flac_frame(flac_frame, pcmreader, options, frame_number, frame)
frame_sizes.append((flac_frame.bytes(), frame.frames))
streaminfo.output_update(flac_frame)
flac_frame.copy(writer)
frame_number += 1
frame = pcmreader.read(block_size)
# return to beginning of file and rewrite STREAMINFO block
writer.setpos(streaminfo_start)
streaminfo.write(writer)
writer.flush()
writer.close()
return frame_sizes
def encode_wavpack(filename, pcmreader, block_size, correlation_passes=0, wave_header=None, wave_footer=None):
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, 1)
context = EncoderContext(
pcmreader,
block_parameters(pcmreader.channels, pcmreader.channel_mask, correlation_passes),
wave_header,
wave_footer,
)
block_index = 0
# walk through PCM reader's FrameLists
frame = pcmreader.read(block_size * (pcmreader.bits_per_sample / 8) * pcmreader.channels)
while len(frame) > 0:
context.total_frames += frame.frames
context.md5sum.update(frame.to_bytes(False, pcmreader.bits_per_sample >= 16))
c = 0
for parameters in context.block_parameters:
if parameters.channel_count == 1:
channel_data = [list(frame.channel(c))]
else:
channel_data = [list(frame.channel(c)), list(frame.channel(c + 1))]
first_block = parameters is context.block_parameters[0]
last_block = parameters is context.block_parameters[-1]
context.block_offsets.append(output_file.tell())
write_block(writer, context, channel_data, block_index, first_block, last_block, parameters)
c += parameters.channel_count
block_index += frame.frames
frame = pcmreader.read(block_size * (pcmreader.bits_per_sample / 8) * pcmreader.channels)
# write MD5 sum and optional Wave footer in final block
sub_blocks = BitstreamRecorder(1)
sub_block = BitstreamRecorder(1)
sub_block.reset()
sub_block.write_bytes(context.md5sum.digest())
write_sub_block(sub_blocks, WV_MD5, 1, sub_block)
# write Wave footer in final block, if present
if context.wave_footer is not None:
sub_block.reset()
sub_block.write_bytes(context.wave_footer)
write_sub_block(sub_blocks, WV_WAVE_FOOTER, 1, sub_block)
write_block_header(
writer,
sub_blocks.bytes(),
0xFFFFFFFF,
0,
pcmreader.bits_per_sample,
1,
0,
0,
0,
1,
1,
0,
pcmreader.sample_rate,
0,
0xFFFFFFFF,
)
sub_blocks.copy(writer)
# update Wave header's "data" chunk size, if generated
if context.wave_header is None:
output_file.seek(32 + 2)
if context.wave_footer is None:
write_wave_header(writer, context.pcmreader, context.total_frames, 0)
else:
write_wave_header(writer, context.pcmreader, context.total_frames, len(context.wave_footer))
# go back and populate block headers with total samples
for block_offset in context.block_offsets:
output_file.seek(block_offset + 12, 0)
writer.write(32, block_index)
writer.close()
def encode_shn(filename,
pcmreader,
is_big_endian,
signed_samples,
header_data,
footer_data=b"",
block_size=256):
"""filename is a string to the output file's path
pcmreader is a PCMReader object
header_data and footer_data are binary strings
block_size is the default size of each Shorten audio command
"""
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, False)
left_shift = 0
wrapped_channels = [[] for c in range(pcmreader.channels)]
# write magic number and version
writer.build("4b 8u", [b"ajkg", 2])
bytes_written = __Counter__()
writer.add_callback(bytes_written.byte)
# write header from PCMReader info and encoding options
if pcmreader.bits_per_sample == 8:
if signed_samples:
write_long(writer, 1) # signed, 8-bit
sign_adjustment = 0
else:
write_long(writer, 2) # unsigned, 8-bit
sign_adjustment = 1 << (pcmreader.bits_per_sample - 1)
# 8-bit samples have no endianness
elif pcmreader.bits_per_sample == 16:
if signed_samples:
if is_big_endian:
write_long(writer, 3) # signed, 16-bit, big-endian
else:
write_long(writer, 5) # signed, 16-bit, little-endian
sign_adjustment = 0
else:
if is_big_endian:
write_long(writer, 4) # unsigned, 16-bit, big-endian
else:
write_long(writer, 6) # unsigned, 16-bit, little-endian
sign_adjustment = 1 << (pcmreader.bits_per_sample - 1)
else:
raise ValueError("unsupported bits_per_sample")
write_long(writer, pcmreader.channels)
write_long(writer, block_size)
write_long(writer, 0) # max LPC
write_long(writer, 0) # mean count
write_long(writer, 0) # bytes to skip
# write header as a VERBATIM block
write_unsigned(writer, COMMAND_SIZE, FN_VERBATIM)
write_unsigned(writer, VERBATIM_SIZE, len(header_data))
for b in bytes_to_ints(header_data):
write_unsigned(writer, VERBATIM_BYTE_SIZE, b)
# split PCMReader into block_size chunks
# and continue until the number of PCM frames is 0
frame = pcmreader.read(block_size)
while len(frame) > 0:
# if the chunk isn't block_size frames long,
# issue a command to change it
if frame.frames != block_size:
block_size = frame.frames
write_unsigned(writer, COMMAND_SIZE, FN_BLOCKSIZE)
write_long(writer, block_size)
# split chunk into individual channels
for c in range(pcmreader.channels):
# convert PCM data to unsigned, if necessary
if signed_samples:
channel = list(frame.channel(c))
else:
channel = [s + sign_adjustment for s in frame.channel(c)]
# if all samples are 0, issue a ZERO command
if all_zeroes(channel):
write_unsigned(writer, COMMAND_SIZE, FN_ZERO)
# wrap zeroes around for next set of channels
wrapped_channels[c] = channel
else:
# if channel's shifted bits have changed
# from the previous channel's shift
# issue a new BITSHIFT command
wasted_bits = wasted_bps(channel)
if wasted_bits != left_shift:
write_unsigned(writer, COMMAND_SIZE, FN_BITSHIFT)
write_unsigned(writer, BITSHIFT_SIZE, wasted_bits)
left_shift = wasted_bits
# and shift the channel's bits if the amount is still > 0
if left_shift > 0:
shifted = [s >> left_shift for s in channel]
else:
shifted = channel
# determine the best DIFF command and residuals
# to issue for shifted channel data
(diff, residuals) = best_diff(wrapped_channels[c], shifted)
# determine the best energy size for DIFF's residuals
energy = best_energy(residuals)
# write DIFF command, energy size and residuals
write_unsigned(writer, COMMAND_SIZE,
{1: FN_DIFF1,
2: FN_DIFF2,
3: FN_DIFF3}[diff])
write_unsigned(writer, ENERGY_SIZE, energy)
for residual in residuals:
write_signed(writer, energy, residual)
# wrap shifted channels around for next set of channels
wrapped_channels[c] = shifted
# and get another set of channels to encode
frame = pcmreader.read(block_size)
# once all PCM data has been sent
# if there's any footer data, write it as another VERBATIM block
if len(footer_data) > 0:
write_unsigned(writer, COMMAND_SIZE, FN_VERBATIM)
write_unsigned(writer, VERBATIM_SIZE, len(footer_data))
for b in bytes_to_ints(footer_data):
write_unsigned(writer, VERBATIM_BYTE_SIZE, b)
# issue a QUIT command
write_unsigned(writer, COMMAND_SIZE, FN_QUIT)
# finally, due to Shorten's silly way of using bit buffers,
# output (not counting the 5 bytes of magic + version)
# must be padded to a multiple of 4 bytes
# or its reference decoder explodes
writer.byte_align()
while (int(bytes_written) % 4) != 0:
writer.write(8, 0)
writer.close()
def encode_flac(filename,
pcmreader,
block_size=4096,
max_lpc_order=8,
min_residual_partition_order=0,
max_residual_partition_order=5,
mid_side=True,
adaptive_mid_side=False,
exhaustive_model_search=False,
disable_verbatim_subframes=False,
disable_constant_subframes=False,
disable_fixed_subframes=False,
disable_lpc_subframes=False,
padding_size=4096):
frame_sizes = []
options = Encoding_Options(block_size,
max_lpc_order,
adaptive_mid_side,
mid_side,
exhaustive_model_search,
max_residual_partition_order,
14 if pcmreader.bits_per_sample <= 16 else 30)
streaminfo = STREAMINFO(block_size,
block_size,
(2 ** 24) - 1,
0,
pcmreader.sample_rate,
pcmreader.channels,
pcmreader.bits_per_sample,
0, md5())
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, False)
# write placeholder metadata blocks such as STREAMINFO and PADDING
writer.write_bytes("fLaC")
writer.build("1u 7u 24u", [0, 0, 34])
streaminfo_start = writer.getpos()
streaminfo.write(writer)
writer.build("1u 7u 24u", [1, 1, padding_size])
writer.write_bytes(b"\x00" * padding_size)
# walk through PCM reader's FrameLists
frame_number = 0
frame = pcmreader.read(block_size)
flac_frame = BitstreamRecorder(0)
while len(frame) > 0:
streaminfo.input_update(frame)
flac_frame.reset()
encode_flac_frame(flac_frame, pcmreader, options, frame_number, frame)
frame_sizes.append((flac_frame.bytes(), frame.frames))
streaminfo.output_update(flac_frame)
flac_frame.copy(writer)
frame_number += 1
frame = pcmreader.read(block_size)
# return to beginning of file and rewrite STREAMINFO block
writer.setpos(streaminfo_start)
streaminfo.write(writer)
writer.flush()
writer.close()
return frame_sizes
def encode_shn(filename,
pcmreader,
is_big_endian,
signed_samples,
header_data,
footer_data=b"",
block_size=256):
"""filename is a string to the output file's path
pcmreader is a PCMReader object
header_data and footer_data are binary strings
block_size is the default size of each Shorten audio command
"""
pcmreader = BufferedPCMReader(pcmreader)
output_file = open(filename, "wb")
writer = BitstreamWriter(output_file, False)
left_shift = 0
wrapped_channels = [[] for c in range(pcmreader.channels)]
# write magic number and version
writer.build("4b 8u", [b"ajkg", 2])
bytes_written = __Counter__()
writer.add_callback(bytes_written.byte)
# write header from PCMReader info and encoding options
if (pcmreader.bits_per_sample == 8):
if (signed_samples):
write_long(writer, 1) # signed, 8-bit
sign_adjustment = 0
else:
write_long(writer, 2) # unsigned, 8-bit
sign_adjustment = 1 << (pcmreader.bits_per_sample - 1)
# 8-bit samples have no endianness
elif (pcmreader.bits_per_sample == 16):
if (signed_samples):
if (is_big_endian):
write_long(writer, 3) # signed, 16-bit, big-endian
else:
write_long(writer, 5) # signed, 16-bit, little-endian
sign_adjustment = 0
else:
if (is_big_endian):
write_long(writer, 4) # unsigned, 16-bit, big-endian
else:
write_long(writer, 6) # unsigned, 16-bit, little-endian
sign_adjustment = 1 << (pcmreader.bits_per_sample - 1)
else:
raise ValueError("unsupported bits_per_sample")
write_long(writer, pcmreader.channels)
write_long(writer, block_size)
write_long(writer, 0) # max LPC
write_long(writer, 0) # mean count
write_long(writer, 0) # bytes to skip
# write header as a VERBATIM block
write_unsigned(writer, COMMAND_SIZE, FN_VERBATIM)
write_unsigned(writer, VERBATIM_SIZE, len(header_data))
for b in bytes_to_ints(header_data):
write_unsigned(writer, VERBATIM_BYTE_SIZE, b)
# split PCMReader into block_size chunks
# and continue until the number of PCM frames is 0
frame = pcmreader.read(block_size)
while (len(frame) > 0):
# if the chunk isn't block_size frames long,
# issue a command to change it
if (frame.frames != block_size):
block_size = frame.frames
write_unsigned(writer, COMMAND_SIZE, FN_BLOCKSIZE)
write_long(writer, block_size)
# split chunk into individual channels
for c in range(pcmreader.channels):
# convert PCM data to unsigned, if necessary
if (signed_samples):
channel = list(frame.channel(c))
else:
channel = [s + sign_adjustment for s in frame.channel(c)]
# if all samples are 0, issue a ZERO command
if (all_zeroes(channel)):
write_unsigned(writer, COMMAND_SIZE, FN_ZERO)
# wrap zeroes around for next set of channels
wrapped_channels[c] = channel
else:
# if channel's shifted bits have changed
# from the previous channel's shift
# issue a new BITSHIFT command
wasted_bits = wasted_bps(channel)
if (wasted_bits != left_shift):
write_unsigned(writer, COMMAND_SIZE, FN_BITSHIFT)
write_unsigned(writer, BITSHIFT_SIZE, wasted_bits)
left_shift = wasted_bits
# and shift the channel's bits if the amount is still > 0
if (left_shift > 0):
shifted = [s >> left_shift for s in channel]
else:
shifted = channel
# determine the best DIFF command and residuals
# to issue for shifted channel data
(diff, residuals) = best_diff(wrapped_channels[c], shifted)
# determine the best energy size for DIFF's residuals
energy = best_energy(residuals)
# write DIFF command, energy size and residuals
write_unsigned(writer, COMMAND_SIZE, {
1: FN_DIFF1,
2: FN_DIFF2,
3: FN_DIFF3
}[diff])
write_unsigned(writer, ENERGY_SIZE, energy)
for residual in residuals:
write_signed(writer, energy, residual)
# wrap shifted channels around for next set of channels
wrapped_channels[c] = shifted
# and get another set of channels to encode
frame = pcmreader.read(block_size)
# once all PCM data has been sent
# if there's any footer data, write it as another VERBATIM block
if (len(footer_data) > 0):
write_unsigned(writer, COMMAND_SIZE, FN_VERBATIM)
write_unsigned(writer, VERBATIM_SIZE, len(footer_data))
for b in bytes_to_ints(footer_data):
write_unsigned(writer, VERBATIM_BYTE_SIZE, b)
# issue a QUIT command
write_unsigned(writer, COMMAND_SIZE, FN_QUIT)
# finally, due to Shorten's silly way of using bit buffers,
# output (not counting the 5 bytes of magic + version)
# must be padded to a multiple of 4 bytes
# or its reference decoder explodes
writer.byte_align()
while ((int(bytes_written) % 4) != 0):
writer.write(8, 0)
writer.close()
def update_metadata(self, metadata):
"""takes this track's current MetaData object
as returned by get_metadata() and sets this track's metadata
with any fields updated in that object
raises IOError if unable to write the file
"""
if metadata is None:
return
elif not isinstance(metadata, ApeTag):
from audiotools.text import ERR_FOREIGN_METADATA
raise ValueError(ERR_FOREIGN_METADATA)
from audiotools.bitstream import parse, BitstreamWriter
from audiotools import transfer_data
f = open(self.filename, "r+b")
f.seek(-32, 2)
tag_footer = f.read(32)
if len(tag_footer) < 32:
# no existing ApeTag can fit, so append fresh tag
f.close()
with BitstreamWriter(open(self.filename, "ab"), True) as writer:
metadata.build(writer)
return
(preamble,
version,
tag_size,
item_count,
read_only,
item_encoding,
is_header,
no_footer,
has_header) = parse(ApeTag.HEADER_FORMAT, True, tag_footer)
if (preamble == b'APETAGEX') and (version == 2000):
if has_header:
old_tag_size = 32 + tag_size
else:
old_tag_size = tag_size
if metadata.total_size() >= old_tag_size:
# metadata has grown
# so append it to existing file
f.seek(-old_tag_size, 2)
writer = BitstreamWriter(f, True)
metadata.build(writer)
writer.close()
else:
f.close()
# metadata has shrunk
# so rewrite file with smaller metadata
from audiotools import TemporaryFile
from os.path import getsize
# copy everything but the last "old_tag_size" bytes
# from existing file to rewritten file
new_apev2 = TemporaryFile(self.filename)
with open(self.filename, "rb") as old_apev2:
limited_transfer_data(
old_apev2.read,
new_apev2.write,
getsize(self.filename) - old_tag_size)
# append new tag to rewritten file
with BitstreamWriter(new_apev2, True) as writer:
metadata.build(writer)
# closing writer closes new_apev2 also
else:
# no existing metadata, so simply append a fresh tag
f.close()
with BitstreamWriter(open(self.filename, "ab"), True) as writer:
metadata.build(writer)
def from_pcm(cls,
filename,
pcmreader,
compression=None,
total_pcm_frames=None,
encoding_function=None):
"""encodes a new file from PCM data
takes a filename string, PCMReader object,
optional compression level string and
optional total_pcm_frames integer
encodes a new audio file from pcmreader's data
at the given filename with the specified compression level
and returns a new AudioFile-compatible object
may raise EncodingError if some problem occurs when
encoding the input file. This includes an error
in the input stream, a problem writing the output file,
or even an EncodingError subclass such as
"UnsupportedBitsPerSample" if the input stream
is formatted in a way this class is unable to support
"""
from audiotools import (BufferedPCMReader, CounterPCMReader,
transfer_data, EncodingError)
# from audiotools.py_encoders import encode_tta
from audiotools.encoders import encode_tta
from audiotools.bitstream import BitstreamWriter
# open output file right away
# so we can fail as soon as possible
try:
file = open(filename, "wb")
except IOError as err:
pcmreader.close()
raise EncodingError(str(err))
writer = BitstreamWriter(file, True)
counter = CounterPCMReader(pcmreader)
try:
if (total_pcm_frames is not None):
# write header to disk
write_header(writer, pcmreader.channels,
pcmreader.bits_per_sample, pcmreader.sample_rate,
total_pcm_frames)
block_size = (pcmreader.sample_rate * 256) // 245
total_tta_frames = div_ceil(total_pcm_frames, block_size)
# write temporary seektable to disk
writer.mark()
write_seektable(writer, [0] * total_tta_frames)
writer.flush()
# write frames to disk
try:
frame_sizes = \
(encode_tta if encoding_function is None
else encoding_function)(file,
BufferedPCMReader(counter))
except (IOError, ValueError) as err:
cls.__unlink__(filename)
raise EncodingError(str(err))
# ensure written number of PCM frames
# matches total_pcm_frames
if (counter.frames_written != total_pcm_frames):
from audiotools.text import ERR_TOTAL_PCM_FRAMES_MISMATCH
cls.__unlink__(filename)
raise EncodingError(ERR_TOTAL_PCM_FRAMES_MISMATCH)
assert (len(frame_sizes) == total_tta_frames)
# go back and rewrite seektable with completed one
writer.rewind()
write_seektable(writer, frame_sizes)
writer.unmark()
else:
import tempfile
frames = tempfile.TemporaryFile()
# encode TTA frames to temporary file
try:
frame_sizes = \
(encode_tta if encoding_function is None
else encoding_function)(frames,
BufferedPCMReader(counter))
except (IOError, ValueError) as err:
frames.close()
cls.__unlink__(filename)
raise EncodingError(str(err))
# write header to disk
write_header(writer, pcmreader.channels,
pcmreader.bits_per_sample, pcmreader.sample_rate,
counter.frames_written)
# write seektable to disk
write_seektable(writer, frame_sizes)
# transfer TTA frames from temporary space to disk
frames.seek(0, 0)
transfer_data(frames.read, writer.write_bytes)
frames.close()
finally:
counter.close()
if (writer.has_mark()):
writer.unmark()
writer.close()
return cls(filename)
def update_metadata(self, metadata):
"""takes this track's current MetaData object
as returned by get_metadata() and sets this track's metadata
with any fields updated in that object
raises IOError if unable to write the file
"""
from audiotools.bitstream import (parse,
BitstreamWriter,
BitstreamReader)
from audiotools import transfer_data
if metadata is None:
return
elif not isinstance(metadata, ApeTag):
from audiotools.text import ERR_FOREIGN_METADATA
raise ValueError(ERR_FOREIGN_METADATA)
elif len(metadata.keys()) == 0:
# wipe out entire block of metadata
from os import access, R_OK, W_OK
if not access(self.filename, R_OK | W_OK):
raise IOError(self.filename)
with open(self.filename, "rb") as f:
f.seek(-32, 2)
(preamble,
version,
tag_size,
item_count,
read_only,
item_encoding,
is_header,
no_footer,
has_header) = BitstreamReader(f, True).parse(
ApeTag.HEADER_FORMAT)
if (preamble == b'APETAGEX') and (version == 2000):
from audiotools import TemporaryFile, transfer_data
from os.path import getsize
# there's existing metadata to delete
# so rewrite file without trailing metadata tag
if has_header:
old_tag_size = 32 + tag_size
else:
old_tag_size = tag_size
# copy everything but the last "old_tag_size" bytes
# from existing file to rewritten file
new_apev2 = TemporaryFile(self.filename)
old_apev2 = open(self.filename, "rb")
limited_transfer_data(
old_apev2.read,
new_apev2.write,
getsize(self.filename) - old_tag_size)
old_apev2.close()
new_apev2.close()
else:
# re-set metadata block at end of file
f = open(self.filename, "r+b")
f.seek(-32, 2)
tag_footer = f.read(32)
if len(tag_footer) < 32:
# no existing ApeTag can fit, so append fresh tag
f.close()
with BitstreamWriter(open(self.filename, "ab"),
True) as writer:
metadata.build(writer)
return
(preamble,
version,
tag_size,
item_count,
read_only,
item_encoding,
is_header,
no_footer,
has_header) = parse(ApeTag.HEADER_FORMAT, True, tag_footer)
if (preamble == b'APETAGEX') and (version == 2000):
if has_header:
old_tag_size = 32 + tag_size
else:
old_tag_size = tag_size
if metadata.total_size() >= old_tag_size:
# metadata has grown
# so append it to existing file
f.seek(-old_tag_size, 2)
writer = BitstreamWriter(f, True)
metadata.build(writer)
writer.close()
else:
f.close()
# metadata has shrunk
# so rewrite file with smaller metadata
from audiotools import TemporaryFile
from os.path import getsize
# copy everything but the last "old_tag_size" bytes
# from existing file to rewritten file
new_apev2 = TemporaryFile(self.filename)
with open(self.filename, "rb") as old_apev2:
limited_transfer_data(
old_apev2.read,
new_apev2.write,
getsize(self.filename) - old_tag_size)
# append new tag to rewritten file
with BitstreamWriter(new_apev2, True) as writer:
metadata.build(writer)
# closing writer closes new_apev2 also
else:
# no existing metadata, so simply append a fresh tag
f.close()
with BitstreamWriter(open(self.filename, "ab"),
True) as writer:
metadata.build(writer)
