mirror of
https://github.com/rembo10/headphones.git
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142 lines
4.3 KiB
Python
142 lines
4.3 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2006 Joe Wreschnig
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# 2014 Christoph Reiter
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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"""WavPack reading and writing.
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WavPack is a lossless format that uses APEv2 tags. Read
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* http://www.wavpack.com/
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* http://www.wavpack.com/file_format.txt
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for more information.
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"""
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__all__ = ["WavPack", "Open", "delete"]
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from mutagen import StreamInfo
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from mutagen.apev2 import APEv2File, error, delete
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from mutagen._util import cdata, convert_error
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class WavPackHeaderError(error):
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pass
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RATES = [6000, 8000, 9600, 11025, 12000, 16000, 22050, 24000, 32000, 44100,
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48000, 64000, 88200, 96000, 192000]
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class _WavPackHeader(object):
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def __init__(self, block_size, version, track_no, index_no, total_samples,
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block_index, block_samples, flags, crc):
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self.block_size = block_size
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self.version = version
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self.track_no = track_no
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self.index_no = index_no
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self.total_samples = total_samples
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self.block_index = block_index
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self.block_samples = block_samples
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self.flags = flags
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self.crc = crc
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@classmethod
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@convert_error(IOError, WavPackHeaderError)
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def from_fileobj(cls, fileobj):
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"""A new _WavPackHeader or raises WavPackHeaderError"""
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header = fileobj.read(32)
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if len(header) != 32 or not header.startswith(b"wvpk"):
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raise WavPackHeaderError("not a WavPack header: %r" % header)
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block_size = cdata.uint_le(header[4:8])
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version = cdata.ushort_le(header[8:10])
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track_no = ord(header[10:11])
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index_no = ord(header[11:12])
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samples = cdata.uint_le(header[12:16])
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if samples == 2 ** 32 - 1:
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samples = -1
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block_index = cdata.uint_le(header[16:20])
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block_samples = cdata.uint_le(header[20:24])
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flags = cdata.uint_le(header[24:28])
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crc = cdata.uint_le(header[28:32])
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return _WavPackHeader(block_size, version, track_no, index_no,
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samples, block_index, block_samples, flags, crc)
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class WavPackInfo(StreamInfo):
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"""WavPack stream information.
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Attributes:
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channels (int): number of audio channels (1 or 2)
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length (float): file length in seconds, as a float
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sample_rate (int): audio sampling rate in Hz
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bits_per_sample (int): audio sample size
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version (int): WavPack stream version
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"""
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def __init__(self, fileobj):
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try:
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header = _WavPackHeader.from_fileobj(fileobj)
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except WavPackHeaderError:
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raise WavPackHeaderError("not a WavPack file")
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self.version = header.version
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self.channels = bool(header.flags & 4) or 2
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self.sample_rate = RATES[(header.flags >> 23) & 0xF]
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self.bits_per_sample = ((header.flags & 3) + 1) * 8
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# most common multiplier (DSD64)
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if (header.flags >> 31) & 1:
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self.sample_rate *= 4
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self.bits_per_sample = 1
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if header.total_samples == -1 or header.block_index != 0:
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# TODO: we could make this faster by using the tag size
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# and search backwards for the last block, then do
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# last.block_index + last.block_samples - initial.block_index
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samples = header.block_samples
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while 1:
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fileobj.seek(header.block_size - 32 + 8, 1)
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try:
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header = _WavPackHeader.from_fileobj(fileobj)
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except WavPackHeaderError:
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break
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samples += header.block_samples
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else:
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samples = header.total_samples
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self.length = float(samples) / self.sample_rate
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def pprint(self):
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return u"WavPack, %.2f seconds, %d Hz" % (self.length,
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self.sample_rate)
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class WavPack(APEv2File):
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"""WavPack(filething)
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Arguments:
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filething (filething)
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Attributes:
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info (`WavPackInfo`)
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"""
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_Info = WavPackInfo
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_mimes = ["audio/x-wavpack"]
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@staticmethod
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def score(filename, fileobj, header):
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return header.startswith(b"wvpk") * 2
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Open = WavPack
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