/usr/lib/python3/dist-packages/audiotools/wav.py is in audiotools 3.1.1-1+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# Copyright (C) 2007-2015 Brian Langenberger
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
from audiotools import (AudioFile, InvalidFile, PCMReader, WaveContainer)
from audiotools.pcm import FrameList
import sys
import struct
class RIFF_Chunk(object):
"""a raw chunk of RIFF WAVE data"""
def __init__(self, chunk_id, chunk_size, chunk_data):
"""chunk_id should be a binary string of ASCII
chunk_data should be a binary string of chunk data"""
# FIXME - check chunk_id's validity
self.id = chunk_id
self.__size__ = chunk_size
self.__data__ = chunk_data
def __repr__(self):
return "RIFF_Chunk(%s)" % (repr(self.id))
def size(self):
"""returns size of chunk in bytes
not including any spacer byte for odd-sized chunks"""
return self.__size__
def total_size(self):
"""returns the total size of the chunk
including the 8 byte ID/size and any padding byte"""
if self.__size__ % 2:
return 8 + self.__size__ + 1
else:
return 8 + self.__size__
def data(self):
"""returns chunk data as file-like object"""
from io import BytesIO
return BytesIO(self.__data__)
def verify(self):
"""returns True if the chunk is sized properly"""
return self.__size__ == len(self.__data__)
def write(self, f):
"""writes the entire chunk to the given output file object
returns size of entire chunk (including header and spacer)
in bytes"""
f.write(self.id)
f.write(struct.pack("<I", self.__size__))
f.write(self.__data__)
if self.__size__ % 2:
f.write(b"\x00")
return self.total_size()
class RIFF_File_Chunk(RIFF_Chunk):
"""a raw chunk of RIFF WAVE data taken from an existing file"""
def __init__(self, chunk_id, chunk_size, wav_file, chunk_data_offset):
"""chunk_id should be a binary string of ASCII
chunk_size is the size of the chunk in bytes
(not counting any spacer byte)
wav_file is the file this chunk belongs to
chunk_data_offset is the offset to the chunk's data bytes
(not including the 8 byte header)"""
self.id = chunk_id
self.__size__ = chunk_size
self.__wav_file__ = wav_file
self.__offset__ = chunk_data_offset
def __del__(self):
self.__wav_file__.close()
def __repr__(self):
return "RIFF_File_Chunk(%s)" % (repr(self.id))
def data(self):
"""returns chunk data as file-like object"""
self.__wav_file__.seek(self.__offset__)
from audiotools import LimitedFileReader
return LimitedFileReader(self.__wav_file__, self.size())
def verify(self):
"""returns True if the chunk is sized properly"""
self.__wav_file__.seek(self.__offset__)
to_read = self.__size__
while to_read > 0:
s = self.__wav_file__.read(min(0x100000, to_read))
if len(s) == 0:
return False
else:
to_read -= len(s)
return True
def write(self, f):
"""writes the entire chunk to the given output file object
returns size of entire chunk (including header and spacer)
in bytes"""
f.write(self.id)
f.write(struct.pack("<I", self.__size__))
self.__wav_file__.seek(self.__offset__)
to_write = self.__size__
while to_write > 0:
s = self.__wav_file__.read(min(0x100000, to_write))
f.write(s)
to_write -= len(s)
if self.__size__ % 2:
f.write(b"\x00")
return self.total_size()
def pad_data(pcm_frames, channels, bits_per_sample):
"""returns True if the given stream combination
requires an extra padding byte at the end of the 'data' chunk"""
return (pcm_frames * channels * (bits_per_sample // 8)) % 2
def validate_header(header):
"""given header string as returned by wave_header_footer(),
returns (total size, data size)
where total size is the size of the file in bytes
and data size is the size of the data chunk in bytes
(not including any padding byte)
the size of the data chunk and of the total file should be validated
after the file has been completely written
such that len(header) + len(data chunk) + len(footer) = total size
raises ValueError if the header is invalid
"""
from io import BytesIO
from audiotools.bitstream import BitstreamReader
header_size = len(header)
wave_file = BitstreamReader(BytesIO(header), True)
try:
# ensure header starts with RIFF<size>WAVE chunk
(riff, remaining_size, wave) = wave_file.parse("4b 32u 4b")
if riff != b"RIFF":
from audiotools.text import ERR_WAV_NOT_WAVE
raise ValueError(ERR_WAV_NOT_WAVE)
elif wave != b"WAVE":
from audiotools.text import ERR_WAV_INVALID_WAVE
raise ValueError(ERR_WAV_INVALID_WAVE)
else:
total_size = remaining_size + 8
header_size -= 12
fmt_found = False
while header_size > 0:
# ensure each chunk header is valid
(chunk_id, chunk_size) = wave_file.parse("4b 32u")
if not frozenset(chunk_id).issubset(WaveAudio.PRINTABLE_ASCII):
from audiotools.text import ERR_WAV_INVALID_CHUNK
raise ValueError(ERR_WAV_INVALID_CHUNK)
else:
header_size -= 8
if chunk_id == b"fmt ":
if not fmt_found:
# skip fmt chunk data when found
fmt_found = True
if chunk_size % 2:
wave_file.skip_bytes(chunk_size + 1)
header_size -= (chunk_size + 1)
else:
wave_file.skip_bytes(chunk_size)
header_size -= chunk_size
else:
# ensure only one fmt chunk is found
from audiotools.text import ERR_WAV_MULTIPLE_FMT
raise ValueError(ERR_WAV_MULTIPLE_FMT)
elif chunk_id == b"data":
if not fmt_found:
# ensure at least one fmt chunk is found
from audiotools.text import ERR_WAV_PREMATURE_DATA
raise ValueError(ERR_WAV_PREMATURE_DATA)
elif header_size > 0:
# ensure no data remains after data chunk header
from audiotools.text import ERR_WAV_HEADER_EXTRA_DATA
raise ValueError(ERR_WAV_HEADER_EXTRA_DATA %
(header_size))
else:
return (total_size, chunk_size)
else:
# skip the full contents of non-audio chunks
if chunk_size % 2:
wave_file.skip_bytes(chunk_size + 1)
header_size -= (chunk_size + 1)
else:
wave_file.skip_bytes(chunk_size)
header_size -= chunk_size
else:
# header parsed with no data chunks found
from audiotools.text import ERR_WAV_NO_DATA_CHUNK
raise ValueError(ERR_WAV_NO_DATA_CHUNK)
except IOError:
from audiotools.text import ERR_WAV_HEADER_IOERROR
raise ValueError(ERR_WAV_HEADER_IOERROR)
def validate_footer(footer, data_bytes_written):
"""given a footer string as returned by wave_header_footer()
and PCM stream parameters, returns True if the footer is valid
raises ValueError if the footer is invalid"""
from io import BytesIO
from audiotools.bitstream import BitstreamReader
total_size = len(footer)
wave_file = BitstreamReader(BytesIO(footer), True)
try:
# ensure footer is padded properly if necessary
# based on size of data bytes written
if data_bytes_written % 2:
wave_file.skip_bytes(1)
total_size -= 1
while total_size > 0:
(chunk_id, chunk_size) = wave_file.parse("4b 32u")
if not frozenset(chunk_id).issubset(WaveAudio.PRINTABLE_ASCII):
from audiotools.text import ERR_WAV_INVALID_CHUNK
raise ValueError(ERR_WAV_INVALID_CHUNK)
else:
total_size -= 8
if chunk_id == b"fmt ":
# ensure no fmt chunks are found
from audiotools.text import ERR_WAV_MULTIPLE_FMT
raise ValueError(ERR_WAV_MULTIPLE_FMT)
elif chunk_id == b"data":
# ensure no data chunks are found
from audiotools.text import ERR_WAV_MULTIPLE_DATA
raise ValueError(ERR_WAV_MULTIPLE_DATA)
else:
# skip the full contents of non-audio chunks
if chunk_size % 2:
wave_file.skip_bytes(chunk_size + 1)
total_size -= (chunk_size + 1)
else:
wave_file.skip_bytes(chunk_size)
total_size -= chunk_size
else:
return True
except IOError:
from audiotools.text import ERR_WAV_FOOTER_IOERROR
raise ValueError(ERR_WAV_FOOTER_IOERROR)
def parse_fmt(fmt):
"""given a fmt block BitstreamReader (without the 8 byte header)
returns (channels, sample_rate, bits_per_sample, channel_mask)
where channel_mask is a ChannelMask object and the rest are ints
may raise ValueError if the fmt chunk is invalid
or IOError if an error occurs parsing the chunk"""
from audiotools import ChannelMask
(compression,
channels,
sample_rate,
bytes_per_second,
block_align,
bits_per_sample) = fmt.parse("16u 16u 32u 32u 16u 16u")
if compression == 1:
# if we have a multi-channel WAVE file
# that's not WAVEFORMATEXTENSIBLE,
# assume the channels follow
# SMPTE/ITU-R recommendations
# and hope for the best
if channels == 1:
channel_mask = ChannelMask.from_fields(
front_center=True)
elif channels == 2:
channel_mask = ChannelMask.from_fields(
front_left=True, front_right=True)
elif channels == 3:
channel_mask = ChannelMask.from_fields(
front_left=True, front_right=True,
front_center=True)
elif channels == 4:
channel_mask = ChannelMask.from_fields(
front_left=True, front_right=True,
back_left=True, back_right=True)
elif channels == 5:
channel_mask = ChannelMask.from_fields(
front_left=True, front_right=True,
back_left=True, back_right=True,
front_center=True)
elif channels == 6:
channel_mask = ChannelMask.from_fields(
front_left=True, front_right=True,
back_left=True, back_right=True,
front_center=True, low_frequency=True)
else:
channel_mask = ChannelMask(0)
return (channels, sample_rate, bits_per_sample, channel_mask)
elif compression == 0xFFFE:
(cb_size,
valid_bits_per_sample,
channel_mask,
sub_format) = fmt.parse("16u 16u 32u 16b")
if (sub_format !=
(b'\x01\x00\x00\x00\x00\x00\x10\x00' +
b'\x80\x00\x00\xaa\x00\x38\x9b\x71')):
# FIXME
raise ValueError("invalid WAVE sub-format")
else:
channel_mask = ChannelMask(channel_mask)
return (channels, sample_rate, bits_per_sample, channel_mask)
else:
# FIXME
raise ValueError("unsupported WAVE compression")
def wave_header(sample_rate,
channels,
channel_mask,
bits_per_sample,
total_pcm_frames):
"""given a set of integer stream attributes,
returns header string of everything before a RIFF WAVE's PCM data
may raise ValueError if the total size of the file is too large"""
from audiotools.bitstream import (BitstreamRecorder, format_size)
assert(isinstance(sample_rate, int))
assert(isinstance(channels, int))
assert(isinstance(channel_mask, int))
assert(isinstance(bits_per_sample, int))
assert(isinstance(total_pcm_frames, int) or
isinstance(total_pcm_frames, long))
header = BitstreamRecorder(True)
avg_bytes_per_second = sample_rate * channels * (bits_per_sample // 8)
block_align = channels * (bits_per_sample // 8)
# build a regular or extended fmt chunk
# based on the reader's attributes
if ((channels <= 2) and (bits_per_sample <= 16)):
fmt = "16u 16u 32u 32u 16u 16u"
fmt_fields = (1, # compression code
channels,
sample_rate,
avg_bytes_per_second,
block_align,
bits_per_sample)
else:
if channel_mask == 0:
channel_mask = {1: 0x4,
2: 0x3,
3: 0x7,
4: 0x33,
5: 0x37,
6: 0x3F}.get(channels, 0)
fmt = "16u 16u 32u 32u 16u 16u" + "16u 16u 32u 16b"
fmt_fields = (0xFFFE, # compression code
channels,
sample_rate,
avg_bytes_per_second,
block_align,
bits_per_sample,
22, # CB size
bits_per_sample,
channel_mask,
b'\x01\x00\x00\x00\x00\x00\x10\x00' +
b'\x80\x00\x00\xaa\x00\x38\x9b\x71' # sub format
)
data_size = (bits_per_sample // 8) * channels * total_pcm_frames
total_size = ((format_size("4b" + "4b 32u" + fmt + "4b 32u") // 8) +
data_size + (data_size % 2))
if total_size < (2 ** 32):
header.build("4b 32u 4b", (b"RIFF", total_size, b"WAVE"))
header.build("4b 32u", (b"fmt ", format_size(fmt) // 8))
header.build(fmt, fmt_fields)
header.build("4b 32u", (b"data", data_size))
return header.data()
else:
raise ValueError("total size too large for wave file")
class WaveReader(object):
"""a PCMReader object for reading wave file contents"""
def __init__(self, wave_filename):
"""wave_filename is a string"""
from audiotools.bitstream import BitstreamReader
self.stream = BitstreamReader(open(wave_filename, "rb"), True)
# ensure RIFF<size>WAVE header is ok
try:
(riff,
total_size,
wave) = self.stream.parse("4b 32u 4b")
except struct.error:
from audiotools.text import ERR_WAV_INVALID_WAVE
self.stream.close()
raise ValueError(ERR_WAV_INVALID_WAVE)
if riff != b'RIFF':
from audiotools.text import ERR_WAV_NOT_WAVE
self.stream.close()
raise ValueError(ERR_WAV_NOT_WAVE)
elif wave != b'WAVE':
from audiotools.text import ERR_WAV_INVALID_WAVE
self.stream.close()
raise ValueError(ERR_WAV_INVALID_WAVE)
else:
total_size -= 4
fmt_chunk_read = False
# walk through chunks until "data" chunk encountered
while total_size > 0:
try:
(chunk_id,
chunk_size) = self.stream.parse("4b 32u")
except struct.error:
from audiotools.text import ERR_WAV_INVALID_WAVE
self.stream.close()
raise ValueError(ERR_WAV_INVALID_WAVE)
if not frozenset(chunk_id).issubset(WaveAudio.PRINTABLE_ASCII):
from audiotools.text import ERR_WAV_INVALID_CHUNK
self.stream.close()
raise ValueError(ERR_WAV_INVALID_CHUNK)
else:
total_size -= 8
if chunk_id == b"fmt ":
# when "fmt " chunk encountered,
# use it to populate PCMReader attributes
(self.channels,
self.sample_rate,
self.bits_per_sample,
channel_mask) = parse_fmt(self.stream)
self.channel_mask = int(channel_mask)
self.bytes_per_pcm_frame = ((self.bits_per_sample // 8) *
self.channels)
fmt_chunk_read = True
elif chunk_id == b"data":
# when "data" chunk encountered,
# use its size to determine total PCM frames
# and ready PCMReader for reading
if not fmt_chunk_read:
from audiotools.text import ERR_WAV_PREMATURE_DATA
self.stream.close()
raise ValueError(ERR_WAV_PREMATURE_DATA)
else:
self.total_pcm_frames = (chunk_size //
self.bytes_per_pcm_frame)
self.remaining_pcm_frames = self.total_pcm_frames
self.data_start = self.stream.getpos()
return
else:
# all other chunks are ignored
self.stream.skip_bytes(chunk_size)
if chunk_size % 2:
if len(self.stream.read_bytes(1)) < 1:
from audiotools.text import ERR_WAV_INVALID_CHUNK
self.stream.close()
raise ValueError(ERR_WAV_INVALID_CHUNK)
total_size -= (chunk_size + 1)
else:
total_size -= chunk_size
else:
# raise an error if no "data" chunk is encountered
from audiotools.text import ERR_WAV_NO_DATA_CHUNK
self.stream.close()
raise ValueError(ERR_WAV_NO_DATA_CHUNK)
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close()
def read(self, pcm_frames):
"""try to read a pcm.FrameList with the given number of PCM frames"""
# try to read requested PCM frames or remaining frames
requested_pcm_frames = min(max(pcm_frames, 1),
self.remaining_pcm_frames)
requested_bytes = (self.bytes_per_pcm_frame *
requested_pcm_frames)
pcm_data = self.stream.read_bytes(requested_bytes)
# raise exception if "data" chunk exhausted early
if len(pcm_data) < requested_bytes:
from audiotools.text import ERR_WAV_TRUNCATED_DATA_CHUNK
raise IOError(ERR_WAV_TRUNCATED_DATA_CHUNK)
else:
self.remaining_pcm_frames -= requested_pcm_frames
# return parsed chunk
return FrameList(pcm_data,
self.channels,
self.bits_per_sample,
False,
self.bits_per_sample != 8)
def read_closed(self, pcm_frames):
raise ValueError("cannot read closed stream")
def seek(self, pcm_frame_offset):
"""tries to seek to the given PCM frame offset
returns the total amount of frames actually seeked over"""
if pcm_frame_offset < 0:
from audiotools.text import ERR_NEGATIVE_SEEK
raise ValueError(ERR_NEGATIVE_SEEK)
# ensure one doesn't walk off the end of the file
pcm_frame_offset = min(pcm_frame_offset, self.total_pcm_frames)
# position file in "data" chunk
self.stream.setpos(self.data_start)
self.stream.seek(pcm_frame_offset * self.bytes_per_pcm_frame, 1)
self.remaining_pcm_frames = (self.total_pcm_frames -
pcm_frame_offset)
return pcm_frame_offset
def seek_closed(self, pcm_frame_offset):
raise ValueError("cannot seek closed stream")
def close(self):
"""closes the stream for reading"""
self.stream.close()
self.read = self.read_closed
self.seek = self.seek_closed
class TempWaveReader(WaveReader):
"""a subclass of WaveReader for reading wave data from temporary files"""
def __init__(self, tempfile):
"""tempfile should be a NamedTemporaryFile
its contents are used to populate the rest of the fields"""
WaveReader.__init__(self, tempfile.name)
self.tempfile = tempfile
def __del__(self):
WaveReader.__del__(self)
self.tempfile.close()
def close(self):
"""closes the input stream and temporary file"""
WaveReader.close(self)
class InvalidWave(InvalidFile):
"""raises during initialization time if a wave file is invalid"""
pass
class WaveAudio(WaveContainer):
"""a waveform audio file"""
SUFFIX = "wav"
NAME = SUFFIX
DESCRIPTION = u"Waveform Audio File Format"
if sys.version_info[0] >= 3:
PRINTABLE_ASCII = {i for i in range(0x20, 0x7E + 1)}
else:
PRINTABLE_ASCII = {chr(i) for i in range(0x20, 0x7E + 1)}
def __init__(self, filename):
"""filename is a plain string"""
from audiotools import ChannelMask
WaveContainer.__init__(self, filename)
self.__channels__ = 0
self.__sample_rate__ = 0
self.__bits_per_sample__ = 0
self.__data_size__ = 0
self.__channel_mask__ = ChannelMask(0)
from audiotools.bitstream import BitstreamReader
fmt_read = data_read = False
try:
for chunk in self.chunks():
if chunk.id == b"fmt ":
try:
(self.__channels__,
self.__sample_rate__,
self.__bits_per_sample__,
self.__channel_mask__) = parse_fmt(
BitstreamReader(chunk.data(), True))
fmt_read = True
if fmt_read and data_read:
break
except IOError:
continue
except ValueError as err:
raise InvalidWave(str(err))
elif chunk.id == b"data":
self.__data_size__ = chunk.size()
data_read = True
if fmt_read and data_read:
break
except IOError:
raise InvalidWave("I/O error reading wave")
def lossless(self):
"""returns True"""
return True
def has_foreign_wave_chunks(self):
"""returns True if the audio file contains non-audio RIFF chunks
during transcoding, if the source audio file has foreign RIFF chunks
and the target audio format supports foreign RIFF chunks,
conversion should be routed through .wav conversion
to avoid losing those chunks"""
return {b'fmt ', b'data'} != {c.id for c in self.chunks()}
def channel_mask(self):
"""returns a ChannelMask object of this track's channel layout"""
return self.__channel_mask__
@classmethod
def supports_to_pcm(cls):
"""returns True if all necessary components are available
to support the .to_pcm() method"""
return True
# Returns the PCMReader object for this WAV's data
def to_pcm(self):
"""returns a PCMReader object containing the track's PCM data"""
try:
return WaveReader(self.filename)
except (IOError, ValueError) as err:
from audiotools import PCMReaderError
return PCMReaderError(error_message=str(err),
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(self.channel_mask()),
bits_per_sample=self.bits_per_sample())
@classmethod
def supports_from_pcm(cls):
"""returns True if all necessary components are available
to support the .from_pcm() classmethod"""
return True
@classmethod
def from_pcm(cls, filename, pcmreader,
compression=None, total_pcm_frames=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 WaveAudio object"""
from audiotools import EncodingError
from audiotools import DecodingError
from audiotools import CounterPCMReader
from audiotools import transfer_framelist_data
try:
header = wave_header(pcmreader.sample_rate,
pcmreader.channels,
pcmreader.channel_mask,
pcmreader.bits_per_sample,
total_pcm_frames if total_pcm_frames
is not None else 0)
except ValueError as err:
pcmreader.close()
raise EncodingError(str(err))
try:
f = open(filename, "wb")
except IOError as err:
pcmreader.close()
raise EncodingError(str(err))
counter = CounterPCMReader(pcmreader)
f.write(header)
try:
transfer_framelist_data(counter,
f.write,
pcmreader.bits_per_sample > 8,
False)
except (IOError, ValueError) as err:
f.close()
cls.__unlink__(filename)
raise EncodingError(str(err))
except Exception as err:
f.close()
cls.__unlink__(filename)
raise err
# handle odd-sized "data" chunks
if counter.frames_written % 2:
f.write(b"\x00")
if total_pcm_frames is not None:
f.close()
if total_pcm_frames != counter.frames_written:
# ensure written number of PCM frames
# matches total_pcm_frames argument
from audiotools.text import ERR_TOTAL_PCM_FRAMES_MISMATCH
cls.__unlink__(filename)
raise EncodingError(ERR_TOTAL_PCM_FRAMES_MISMATCH)
else:
# go back and rewrite populated header
# with counted number of PCM frames
f.seek(0, 0)
f.write(wave_header(pcmreader.sample_rate,
pcmreader.channels,
pcmreader.channel_mask,
pcmreader.bits_per_sample,
counter.frames_written))
f.close()
return WaveAudio(filename)
def total_frames(self):
"""returns the total PCM frames of the track as an integer"""
return (self.__data_size__ //
(self.__bits_per_sample__ // 8) //
self.__channels__)
def sample_rate(self):
"""returns the rate of the track's audio as an integer number of Hz"""
return self.__sample_rate__
def channels(self):
"""returns an integer number of channels this track contains"""
return self.__channels__
def bits_per_sample(self):
"""returns an integer number of bits-per-sample this track contains"""
return self.__bits_per_sample__
def seekable(self):
"""returns True if the file is seekable"""
return True
@classmethod
def track_name(cls, file_path, track_metadata=None, format=None):
"""constructs a new filename string
given a plain string to an existing path,
a MetaData-compatible object (or None),
a UTF-8-encoded Python format string
and an ASCII-encoded suffix string (such as "mp3")
returns a plain string of a new filename with format's
fields filled-in and encoded as FS_ENCODING
raises UnsupportedTracknameField if the format string
contains invalid template fields"""
if format is None:
format = "track%(track_number)2.2d.wav"
return AudioFile.track_name(file_path, track_metadata, format,
suffix=cls.SUFFIX)
def chunks(self):
"""yields a set of RIFF_Chunk or RIFF_File_Chunk objects"""
with open(self.filename, "rb") as wave_file:
try:
(riff,
total_size,
wave) = struct.unpack("<4sI4s", wave_file.read(12))
except struct.error:
from audiotools.text import ERR_WAV_INVALID_WAVE
raise InvalidWave(ERR_WAV_INVALID_WAVE)
if riff != b'RIFF':
from audiotools.text import ERR_WAV_NOT_WAVE
raise InvalidWave(ERR_WAV_NOT_WAVE)
elif wave != b'WAVE':
from audiotools.text import ERR_WAV_INVALID_WAVE
raise InvalidWave(ERR_WAV_INVALID_WAVE)
else:
total_size -= 4
while total_size > 0:
# read the chunk header and ensure its validity
try:
(chunk_id,
chunk_size) = struct.unpack("<4sI", wave_file.read(8))
except struct.error:
from audiotools.text import ERR_WAV_INVALID_WAVE
raise InvalidWave(ERR_WAV_INVALID_WAVE)
if not frozenset(chunk_id).issubset(self.PRINTABLE_ASCII):
from audiotools.text import ERR_WAV_INVALID_CHUNK
raise InvalidWave(ERR_WAV_INVALID_CHUNK)
else:
total_size -= 8
# yield RIFF_Chunk or RIFF_File_Chunk depending on chunk size
if chunk_size >= 0x100000:
# if chunk is too large, yield a File_Chunk
yield RIFF_File_Chunk(chunk_id,
chunk_size,
open(self.filename, "rb"),
wave_file.tell())
wave_file.seek(chunk_size, 1)
else:
# otherwise, yield a raw data Chunk
yield RIFF_Chunk(chunk_id, chunk_size,
wave_file.read(chunk_size))
if chunk_size % 2:
if len(wave_file.read(1)) < 1:
from audiotools.text import ERR_WAV_INVALID_CHUNK
raise InvalidWave(ERR_WAV_INVALID_CHUNK)
total_size -= (chunk_size + 1)
else:
total_size -= chunk_size
@classmethod
def wave_from_chunks(cls, filename, chunk_iter):
"""builds a new RIFF WAVE file from a chunk data iterator
filename is the path to the wave file to build
chunk_iter should yield RIFF_Chunk-compatible objects
"""
with open(filename, 'wb') as wave_file:
total_size = 4
# write an unfinished header with a placeholder size
wave_file.write(
struct.pack("<4sI4s", b"RIFF", total_size, b"WAVE"))
# write the individual chunks
for chunk in chunk_iter:
total_size += chunk.write(wave_file)
# once the chunks are done, go back and re-write the header
wave_file.seek(0, 0)
wave_file.write(
struct.pack("<4sI4s", b"RIFF", total_size, b"WAVE"))
def wave_header_footer(self):
"""returns a pair of data strings before and after PCM data
the first contains all data before the PCM content of the data chunk
the second containing all data after the data chunk
for example:
>>> w = audiotools.open("input.wav")
>>> (head, tail) = w.wave_header_footer()
>>> f = open("output.wav", "wb")
>>> f.write(head)
>>> audiotools.transfer_framelist_data(w.to_pcm(), f.write)
>>> f.write(tail)
>>> f.close()
should result in "output.wav" being identical to "input.wav"
"""
from audiotools.bitstream import BitstreamReader
from audiotools.bitstream import BitstreamRecorder
head = BitstreamRecorder(1)
tail = BitstreamRecorder(1)
current_block = head
fmt_found = False
with BitstreamReader(open(self.filename, 'rb'), 1) as wave_file:
# transfer the 12-byte "RIFFsizeWAVE" header to head
(riff, size, wave) = wave_file.parse("4b 32u 4b")
if riff != b'RIFF':
from audiotools.text import ERR_WAV_NOT_WAVE
raise ValueError(ERR_WAV_NOT_WAVE)
elif wave != b'WAVE':
from audiotools.text import ERR_WAV_INVALID_WAVE
raise ValueError(ERR_WAV_INVALID_WAVE)
else:
current_block.build("4b 32u 4b", (riff, size, wave))
total_size = size - 4
while total_size > 0:
# transfer each chunk header
(chunk_id, chunk_size) = wave_file.parse("4b 32u")
if not frozenset(chunk_id).issubset(self.PRINTABLE_ASCII):
from audiotools.text import ERR_WAV_INVALID_CHUNK
raise ValueError(ERR_WAV_INVALID_CHUNK)
else:
current_block.build("4b 32u", (chunk_id, chunk_size))
total_size -= 8
# and transfer the full content of non-audio chunks
if chunk_id != b"data":
if chunk_id == b"fmt ":
if not fmt_found:
fmt_found = True
else:
from audiotools.text import ERR_WAV_MULTIPLE_FMT
raise ValueError(ERR_WAV_MULTIPLE_FMT)
if chunk_size % 2:
current_block.write_bytes(
wave_file.read_bytes(chunk_size + 1))
total_size -= (chunk_size + 1)
else:
current_block.write_bytes(
wave_file.read_bytes(chunk_size))
total_size -= chunk_size
else:
wave_file.skip_bytes(chunk_size)
current_block = tail
if chunk_size % 2:
current_block.write_bytes(wave_file.read_bytes(1))
total_size -= (chunk_size + 1)
else:
total_size -= chunk_size
if fmt_found:
return (head.data(), tail.data())
else:
from audiotools.text import ERR_WAV_NO_FMT_CHUNK
raise ValueError(ERR_WAV_NO_FMT_CHUNK)
@classmethod
def from_wave(cls, filename, header, pcmreader, footer, compression=None):
"""encodes a new file from wave data
takes a filename string, header string,
PCMReader object, footer string
and optional compression level string
encodes a new audio file from pcmreader's data
at the given filename with the specified compression level
and returns a new WaveAudio object
header + pcm data + footer should always result
in the original wave file being restored
without need for any padding bytes
may raise EncodingError if some problem occurs when
encoding the input file"""
from audiotools import (DecodingError, EncodingError, FRAMELIST_SIZE)
from struct import unpack
# ensure header validates correctly
try:
(total_size, data_size) = validate_header(header)
except ValueError as err:
pcmreader.close()
raise EncodingError(str(err))
try:
f = open(filename, "wb")
except IOError as msg:
pcmreader.close()
raise EncodingError(err)
try:
# write header to output file
f.write(header)
# write PCM data to output file
data_bytes_written = 0
signed = (pcmreader.bits_per_sample > 8)
s = pcmreader.read(FRAMELIST_SIZE).to_bytes(False, signed)
while len(s) > 0:
data_bytes_written += len(s)
f.write(s)
s = pcmreader.read(FRAMELIST_SIZE).to_bytes(False, signed)
# ensure output data size matches the "data" chunk's size
if data_size != data_bytes_written:
cls.__unlink__(filename)
from audiotools.text import ERR_WAV_TRUNCATED_DATA_CHUNK
raise EncodingError(ERR_WAV_TRUNCATED_DATA_CHUNK)
# ensure footer validates correctly
# before writing it to disk
validate_footer(footer, data_bytes_written)
f.write(footer)
f.flush()
# ensure total size is correct
if (len(header) + data_size + len(footer)) != total_size:
cls.__unlink__(filename)
from audiotools.text import ERR_WAV_INVALID_SIZE
raise EncodingError(ERR_WAV_INVALID_SIZE)
return cls(filename)
except (IOError, ValueError) as err:
cls.__unlink__(filename)
raise EncodingError(str(err))
finally:
f.close()
pcmreader.close()
def verify(self, progress=None):
"""verifies the current file for correctness
returns True if the file is okay
raises an InvalidFile with an error message if there is
some problem with the file"""
from audiotools import CounterPCMReader
from audiotools import transfer_framelist_data
from audiotools import to_pcm_progress
try:
(header, footer) = self.wave_header_footer()
except IOError as err:
raise InvalidWave(err)
except ValueError as err:
raise InvalidWave(err)
# ensure header is valid
try:
(total_size, data_size) = validate_header(header)
except ValueError as err:
raise InvalidWave(err)
# ensure "data" chunk has all its data
counter = CounterPCMReader(to_pcm_progress(self, progress))
try:
transfer_framelist_data(counter, lambda f: f)
except (IOError, ValueError):
from audiotools.text import ERR_WAV_TRUNCATED_DATA_CHUNK
raise InvalidWave(ERR_WAV_TRUNCATED_DATA_CHUNK)
data_bytes_written = counter.bytes_written()
# ensure output data size matches the "data" chunk's size
if data_size != data_bytes_written:
from audiotools.text import ERR_WAV_TRUNCATED_DATA_CHUNK
raise InvalidWave(ERR_WAV_TRUNCATED_DATA_CHUNK)
# ensure footer validates correctly
try:
validate_footer(footer, data_bytes_written)
except ValueError as err:
from audiotools.text import ERR_WAV_INVALID_SIZE
raise InvalidWave(ERR_WAV_INVALID_SIZE)
# ensure total size is correct
if (len(header) + data_size + len(footer)) != total_size:
from audiotools.text import ERR_WAV_INVALID_SIZE
raise InvalidWave(ERR_WAV_INVALID_SIZE)
return True
def clean(self, output_filename=None):
"""cleans the file of known data and metadata problems
output_filename is an optional filename of the fixed file
if present, a new AudioFile is written to that path
otherwise, only a dry-run is performed and no new file is written
return list of fixes performed as Unicode strings
raises IOError if unable to write the file or its metadata
raises ValueError if the file has errors of some sort
"""
fixes_performed = []
chunk_queue = []
pending_data = None
for chunk in self.chunks():
if chunk.id == b"fmt ":
if b"fmt " in [c.id for c in chunk_queue]:
from audiotools.text import CLEAN_WAV_MULTIPLE_FMT_CHUNKS
fixes_performed.append(CLEAN_WAV_MULTIPLE_FMT_CHUNKS)
else:
chunk_queue.append(chunk)
if pending_data is not None:
chunk_queue.append(pending_data)
pending_data = None
elif chunk.id == b"data":
if b"fmt " not in [c.id for c in chunk_queue]:
from audiotools.text import CLEAN_WAV_REORDERED_DATA_CHUNK
fixes_performed.append(CLEAN_WAV_REORDERED_DATA_CHUNK)
pending_data = chunk
elif b"data" in [c.id for c in chunk_queue]:
from audiotools.text import CLEAN_WAV_MULTIPLE_DATA_CHUNKS
fixes_performed.append(CLEAN_WAV_MULTIPLE_DATA_CHUNKS)
else:
chunk_queue.append(chunk)
else:
chunk_queue.append(chunk)
if output_filename is not None:
WaveAudio.wave_from_chunks(output_filename, chunk_queue)
return fixes_performed
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