def write_block(writer, context, channels, block_index, first_block, last_block, parameters):
"""writer is a BitstreamWriter-compatible object
context is an EncoderContext object
channels[c][s] is sample "s" in channel "c"
block_index is an integer of the block's offset in PCM frames
first_block and last_block are flags indicating the block's sequence
parameters is an EncodingParameters object
"""
assert (len(channels) == 1) or (len(channels) == 2)
if (len(channels) == 1) or (channels[0] == channels[1]):
# 1 channel block or equivalent
if len(channels) == 1:
false_stereo = 0
else:
false_stereo = 1
# calculate maximum magnitude of channel_0
magnitude = max(map(bits, channels[0]))
# determine wasted bits
wasted = min(map(wasted_bps, channels[0]))
if wasted == INFINITY:
# all samples are 0
wasted = 0
# if wasted bits, remove them from channel_0
if (wasted > 0) and (wasted != INFINITY):
shifted = [[s >> wasted for s in channels[0]]]
else:
shifted = [channels[0]]
# calculate CRC of shifted_0
crc = calculate_crc(shifted)
else:
# 2 channel block
false_stereo = 0
# calculate maximum magnitude of channel_0/channel_1
magnitude = max(max(map(bits, channels[0])), max(map(bits, channels[1])))
# determine wasted bits
wasted = min(min(map(wasted_bps, channels[0])), min(map(wasted_bps, channels[1])))
if wasted == INFINITY:
# all samples are 0
wasted = 0
# if wasted bits, remove them from channel_0/channel_1
if wasted > 0:
shifted = [[s >> wasted for s in channels[0]], [s >> wasted for s in channels[1]]]
else:
shifted = channels
# calculate CRC of shifted_0/shifted_1
crc = calculate_crc(shifted)
# joint stereo conversion of shifted_0/shifted_1 to mid/side channels
mid_side = joint_stereo(shifted[0], shifted[1])
sub_blocks = BitstreamRecorder(1)
sub_block = BitstreamRecorder(1)
# if first block in file, write Wave header
if not context.first_block_written:
sub_block.reset()
if context.wave_header is None:
if context.wave_footer is None:
write_wave_header(sub_block, context.pcmreader, 0, 0)
else:
write_wave_header(sub_block, context.pcmreader, 0, len(context.wave_footer))
else:
sub_block.write_bytes(context.wave_header)
write_sub_block(sub_blocks, WV_WAVE_HEADER, 1, sub_block)
context.first_block_written = True
# if correlation passes, write three sub blocks of pass data
if parameters.correlation_passes > 0:
sub_block.reset()
write_correlation_terms(
sub_block,
[p.term for p in parameters.correlation_parameters(false_stereo)],
[p.delta for p in parameters.correlation_parameters(false_stereo)],
)
write_sub_block(sub_blocks, WV_TERMS, 0, sub_block)
sub_block.reset()
write_correlation_weights(sub_block, [p.weights for p in parameters.correlation_parameters(false_stereo)])
write_sub_block(sub_blocks, WV_WEIGHTS, 0, sub_block)
sub_block.reset()
write_correlation_samples(
sub_block,
[p.term for p in parameters.correlation_parameters(false_stereo)],
[p.samples for p in parameters.correlation_parameters(false_stereo)],
2 if ((len(channels) == 2) and (not false_stereo)) else 1,
)
write_sub_block(sub_blocks, WV_SAMPLES, 0, sub_block)
# if wasted bits, write extended integers sub block
if wasted > 0:
sub_block.reset()
write_extended_integers(sub_block, 0, wasted, 0, 0)
write_sub_block(sub_blocks, WV_INT32_INFO, 0, sub_block)
# if channel count > 2, write channel info sub block
if context.pcmreader.channels > 2:
sub_block.reset()
sub_block.write(8, context.pcmreader.channels)
sub_block.write(32, context.pcmreader.channel_mask)
write_sub_block(sub_blocks, WV_CHANNEL_INFO, 0, sub_block)
# if nonstandard sample rate, write sample rate sub block
if context.pcmreader.sample_rate not in (
6000,
8000,
9600,
11025,
12000,
16000,
22050,
24000,
32000,
44100,
48000,
64000,
88200,
96000,
192000,
):
sub_block.reset()
sub_block.write(32, context.pcmreader.sample_rate)
write_sub_block(sub_blocks, WV_SAMPLE_RATE, 1, sub_block)
if (len(channels) == 1) or (false_stereo):
# 1 channel block
# correlate shifted_0 with terms/deltas/weights/samples
if parameters.correlation_passes > 0:
assert len(shifted) == 1
correlated = correlate_channels(shifted, parameters.correlation_parameters(false_stereo), 1)
else:
correlated = shifted
else:
# 2 channel block
# correlate shifted_0/shifted_1 with terms/deltas/weights/samples
if parameters.correlation_passes > 0:
assert len(mid_side) == 2
correlated = correlate_channels(mid_side, parameters.correlation_parameters(false_stereo), 2)
else:
correlated = mid_side
# write entropy variables sub block
sub_block.reset()
write_entropy_variables(sub_block, correlated, parameters.entropy_variables)
write_sub_block(sub_blocks, WV_ENTROPY, 0, sub_block)
# write bitstream sub block
sub_block.reset()
write_bitstream(sub_block, correlated, parameters.entropy_variables)
write_sub_block(sub_blocks, WV_BITSTREAM, 0, sub_block)
# write block header with size of all sub blocks
write_block_header(
writer,
sub_blocks.bytes(),
block_index,
len(channels[0]),
context.pcmreader.bits_per_sample,
len(channels),
(len(channels) == 2) and (false_stereo == 0),
len(set([-1, -2, -3]) & set([p.term for p in parameters.correlation_parameters(false_stereo)])) > 0,
wasted,
first_block,
last_block,
magnitude,
context.pcmreader.sample_rate,
false_stereo,
crc,
)
# write sub block data to stream
sub_blocks.copy(writer)
# round-trip entropy variables
parameters.entropy_variables = [
[wv_exp2(wv_log2(p)) for p in parameters.entropy_variables[0]],
[wv_exp2(wv_log2(p)) for p in parameters.entropy_variables[1]],
]
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
"""
import os
from audiotools import TemporaryFile
from audiotools.ogg import (PageReader,
PacketReader,
PageWriter,
packet_to_pages,
packets_to_pages)
from audiotools.bitstream import BitstreamRecorder
if metadata is None:
return
elif not isinstance(metadata, VorbisComment):
from audiotools.text import ERR_FOREIGN_METADATA
raise ValueError(ERR_FOREIGN_METADATA)
elif not os.access(self.filename, os.W_OK):
raise IOError(self.filename)
original_ogg = PacketReader(PageReader(open(self.filename, "rb")))
new_ogg = PageWriter(TemporaryFile(self.filename))
sequence_number = 0
# transfer current file's identification packet in its own page
identification_packet = original_ogg.read_packet()
for (i, page) in enumerate(packet_to_pages(
identification_packet,
self.__serial_number__,
starting_sequence_number=sequence_number)):
page.stream_beginning = (i == 0)
new_ogg.write(page)
sequence_number += 1
# discard the current file's comment packet
comment_packet = original_ogg.read_packet()
# generate new comment packet
comment_writer = BitstreamRecorder(True)
comment_writer.write_bytes(b"OpusTags")
vendor_string = metadata.vendor_string.encode('utf-8')
comment_writer.build("32u %db" % (len(vendor_string)),
(len(vendor_string), vendor_string))
comment_writer.write(32, len(metadata.comment_strings))
for comment_string in metadata.comment_strings:
comment_string = comment_string.encode('utf-8')
comment_writer.build("32u %db" % (len(comment_string)),
(len(comment_string), comment_string))
for page in packet_to_pages(
comment_writer.data(),
self.__serial_number__,
starting_sequence_number=sequence_number):
new_ogg.write(page)
sequence_number += 1
# transfer remaining pages after re-sequencing
page = original_ogg.read_page()
page.sequence_number = sequence_number
sequence_number += 1
new_ogg.write(page)
while not page.stream_end:
page = original_ogg.read_page()
page.sequence_number = sequence_number
page.bitstream_serial_number = self.__serial_number__
sequence_number += 1
new_ogg.write(page)
original_ogg.close()
new_ogg.close()
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 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
"""
import os
from audiotools import TemporaryFile
from audiotools.ogg import (PageReader, PacketReader, PageWriter,
packet_to_pages, packets_to_pages)
from audiotools.bitstream import BitstreamRecorder
if (metadata is None):
return
elif (not isinstance(metadata, VorbisComment)):
from audiotools.text import ERR_FOREIGN_METADATA
raise ValueError(ERR_FOREIGN_METADATA)
elif (not os.access(self.filename, os.W_OK)):
raise IOError(self.filename)
original_ogg = PacketReader(PageReader(open(self.filename, "rb")))
new_ogg = PageWriter(TemporaryFile(self.filename))
sequence_number = 0
# transfer current file's identification packet in its own page
identification_packet = original_ogg.read_packet()
for (i, page) in enumerate(
packet_to_pages(identification_packet,
self.__serial_number__,
starting_sequence_number=sequence_number)):
page.stream_beginning = (i == 0)
new_ogg.write(page)
sequence_number += 1
# discard the current file's comment packet
comment_packet = original_ogg.read_packet()
# generate new comment packet
comment_writer = BitstreamRecorder(True)
comment_writer.write_bytes("OpusTags")
vendor_string = metadata.vendor_string.encode('utf-8')
comment_writer.build("32u %db" % (len(vendor_string)),
(len(vendor_string), vendor_string))
comment_writer.write(32, len(metadata.comment_strings))
for comment_string in metadata.comment_strings:
comment_string = comment_string.encode('utf-8')
comment_writer.build("32u %db" % (len(comment_string)),
(len(comment_string), comment_string))
for page in packet_to_pages(comment_writer.data(),
self.__serial_number__,
starting_sequence_number=sequence_number):
new_ogg.write(page)
sequence_number += 1
# transfer remaining pages after re-sequencing
page = original_ogg.read_page()
page.sequence_number = sequence_number
sequence_number += 1
new_ogg.write(page)
while (not page.stream_end):
page = original_ogg.read_page()
page.sequence_number = sequence_number
page.bitstream_serial_number = self.__serial_number__
sequence_number += 1
new_ogg.write(page)
original_ogg.close()
new_ogg.close()
