def _parse_dac3(self, atom, fileobj):
# ETSI TS 102 366
assert atom.name == b"dac3"
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % atom.name)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
# sample_rate in AudioSampleEntry covers values in
# fscod2 and not just fscod, so ignore fscod here.
try:
r.skip(2 + 5 + 3) # fscod, bsid, bsmod
acmod = r.bits(3)
lfeon = r.bits(1)
bit_rate_code = r.bits(5)
r.skip(5) # reserved
except BitReaderError as e:
raise ASEntryError(e)
self.channels = [2, 1, 2, 3, 3, 4, 4, 5][acmod] + lfeon
try:
self.bitrate = [
32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,
384, 448, 512, 576, 640
][bit_rate_code] * 1000
except IndexError:
pass
def _parse_dac3(self, atom, fileobj):
# ETSI TS 102 366
assert atom.name == b"dac3"
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % atom.name)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
# sample_rate in AudioSampleEntry covers values in
# fscod2 and not just fscod, so ignore fscod here.
try:
r.skip(2 + 5 + 3) # fscod, bsid, bsmod
acmod = r.bits(3)
lfeon = r.bits(1)
bit_rate_code = r.bits(5)
r.skip(5) # reserved
except BitReaderError as e:
raise ASEntryError(e)
self.channels = [2, 1, 2, 3, 3, 4, 4, 5][acmod] + lfeon
try:
self.bitrate = [
32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192,
224, 256, 320, 384, 448, 512, 576, 640][bit_rate_code] * 1000
except IndexError:
pass
def _parse_stsd(self, atom, fileobj):
"""Sets channels, bits_per_sample, sample_rate and optionally bitrate.
Can raise MP4StreamInfoError.
"""
assert atom.name == b"stsd"
ok, data = atom.read(fileobj)
if not ok:
raise MP4StreamInfoError("Invalid stsd")
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise MP4StreamInfoError(e)
if version != 0:
raise MP4StreamInfoError("Unsupported stsd version")
try:
num_entries, offset = cdata.uint32_be_from(data, 0)
except cdata.error as e:
raise MP4StreamInfoError(e)
if num_entries == 0:
return
# look at the first entry if there is one
entry_fileobj = cBytesIO(data[offset:])
try:
entry_atom = Atom(entry_fileobj)
except AtomError as e:
raise MP4StreamInfoError(e)
try:
entry = AudioSampleEntry(entry_atom, entry_fileobj)
except ASEntryError as e:
raise MP4StreamInfoError(e)
else:
self.channels = entry.channels
self.bits_per_sample = entry.sample_size
self.sample_rate = entry.sample_rate
self.bitrate = entry.bitrate
self.codec = entry.codec
self.codec_description = entry.codec_description
def _parse_stsd(self, atom, fileobj):
"""Sets channels, bits_per_sample, sample_rate and optionally bitrate.
Can raise MP4StreamInfoError.
"""
assert atom.name == b"stsd"
ok, data = atom.read(fileobj)
if not ok:
raise MP4StreamInfoError("Invalid stsd")
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise MP4StreamInfoError(e)
if version != 0:
raise MP4StreamInfoError("Unsupported stsd version")
try:
num_entries, offset = cdata.uint32_be_from(data, 0)
except cdata.error as e:
raise MP4StreamInfoError(e)
if num_entries == 0:
return
# look at the first entry if there is one
entry_fileobj = cBytesIO(data[offset:])
try:
entry_atom = Atom(entry_fileobj)
except AtomError as e:
raise MP4StreamInfoError(e)
try:
entry = AudioSampleEntry(entry_atom, entry_fileobj)
except ASEntryError as e:
raise MP4StreamInfoError(e)
else:
self.channels = entry.channels
self.bits_per_sample = entry.sample_size
self.sample_rate = entry.sample_rate
self.bitrate = entry.bitrate
self.codec = entry.codec
self.codec_description = entry.codec_description
def _parse_esds(self, esds, fileobj):
assert esds.name == b"esds"
ok, data = esds.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % esds.name)
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise ASEntryError(e)
if version != 0:
raise ASEntryError("Unsupported version %d" % version)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
tag = r.bits(8)
if tag != ES_Descriptor.TAG:
raise ASEntryError("unexpected descriptor: %d" % tag)
assert r.is_aligned()
except BitReaderError as e:
raise ASEntryError(e)
try:
decSpecificInfo = ES_Descriptor.parse(fileobj)
except DescriptorError as e:
raise ASEntryError(e)
dec_conf_desc = decSpecificInfo.decConfigDescr
self.bitrate = dec_conf_desc.avgBitrate
self.codec += dec_conf_desc.codec_param
self.codec_description = dec_conf_desc.codec_desc
decSpecificInfo = dec_conf_desc.decSpecificInfo
if decSpecificInfo is not None:
if decSpecificInfo.channels != 0:
self.channels = decSpecificInfo.channels
if decSpecificInfo.sample_rate != 0:
self.sample_rate = decSpecificInfo.sample_rate
def _parse_esds(self, esds, fileobj):
assert esds.name == b"esds"
ok, data = esds.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % esds.name)
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise ASEntryError(e)
if version != 0:
raise ASEntryError("Unsupported version %d" % version)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
tag = r.bits(8)
if tag != ES_Descriptor.TAG:
raise ASEntryError("unexpected descriptor: %d" % tag)
assert r.is_aligned()
except BitReaderError as e:
raise ASEntryError(e)
try:
decSpecificInfo = ES_Descriptor.parse(fileobj)
except DescriptorError as e:
raise ASEntryError(e)
dec_conf_desc = decSpecificInfo.decConfigDescr
self.bitrate = dec_conf_desc.avgBitrate
self.codec += dec_conf_desc.codec_param
self.codec_description = dec_conf_desc.codec_desc
decSpecificInfo = dec_conf_desc.decSpecificInfo
if decSpecificInfo is not None:
if decSpecificInfo.channels != 0:
self.channels = decSpecificInfo.channels
if decSpecificInfo.sample_rate != 0:
self.sample_rate = decSpecificInfo.sample_rate
def __init__(self, atom, fileobj):
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("too short %r atom" % atom.name)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
# SampleEntry
r.skip(6 * 8) # reserved
r.skip(2 * 8) # data_ref_index
# AudioSampleEntry
r.skip(8 * 8) # reserved
self.channels = r.bits(16)
self.sample_size = r.bits(16)
r.skip(2 * 8) # pre_defined
r.skip(2 * 8) # reserved
self.sample_rate = r.bits(32) >> 16
except BitReaderError as e:
raise ASEntryError(e)
assert r.is_aligned()
try:
extra = Atom(fileobj)
except AtomError as e:
raise ASEntryError(e)
self.codec = atom.name.decode("latin-1")
self.codec_description = None
if atom.name == b"mp4a" and extra.name == b"esds":
self._parse_esds(extra, fileobj)
elif atom.name == b"alac" and extra.name == b"alac":
self._parse_alac(extra, fileobj)
elif atom.name == b"ac-3" and extra.name == b"dac3":
self._parse_dac3(extra, fileobj)
if self.codec_description is None:
self.codec_description = self.codec.upper()
def __init__(self, atom, fileobj):
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("too short %r atom" % atom.name)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
# SampleEntry
r.skip(6 * 8) # reserved
r.skip(2 * 8) # data_ref_index
# AudioSampleEntry
r.skip(8 * 8) # reserved
self.channels = r.bits(16)
self.sample_size = r.bits(16)
r.skip(2 * 8) # pre_defined
r.skip(2 * 8) # reserved
self.sample_rate = r.bits(32) >> 16
except BitReaderError as e:
raise ASEntryError(e)
assert r.is_aligned()
try:
extra = Atom(fileobj)
except AtomError as e:
raise ASEntryError(e)
self.codec = atom.name.decode("latin-1")
self.codec_description = None
if atom.name == b"mp4a" and extra.name == b"esds":
self._parse_esds(extra, fileobj)
elif atom.name == b"alac" and extra.name == b"alac":
self._parse_alac(extra, fileobj)
elif atom.name == b"ac-3" and extra.name == b"dac3":
self._parse_dac3(extra, fileobj)
if self.codec_description is None:
self.codec_description = self.codec.upper()
def _parse_alac(self, atom, fileobj):
# https://alac.macosforge.org/trac/browser/trunk/
# ALACMagicCookieDescription.txt
assert atom.name == b"alac"
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % atom.name)
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise ASEntryError(e)
if version != 0:
raise ASEntryError("Unsupported version %d" % version)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
# for some files the AudioSampleEntry values default to 44100/2chan
# and the real info is in the alac cookie, so prefer it
r.skip(32) # frameLength
compatibleVersion = r.bits(8)
if compatibleVersion != 0:
return
self.sample_size = r.bits(8)
r.skip(8 + 8 + 8)
self.channels = r.bits(8)
r.skip(16 + 32)
self.bitrate = r.bits(32)
self.sample_rate = r.bits(32)
except BitReaderError as e:
raise ASEntryError(e)
def _parse_alac(self, atom, fileobj):
# https://alac.macosforge.org/trac/browser/trunk/
# ALACMagicCookieDescription.txt
assert atom.name == b"alac"
ok, data = atom.read(fileobj)
if not ok:
raise ASEntryError("truncated %s atom" % atom.name)
try:
version, flags, data = parse_full_atom(data)
except ValueError as e:
raise ASEntryError(e)
if version != 0:
raise ASEntryError("Unsupported version %d" % version)
fileobj = cBytesIO(data)
r = BitReader(fileobj)
try:
# for some files the AudioSampleEntry values default to 44100/2chan
# and the real info is in the alac cookie, so prefer it
r.skip(32) # frameLength
compatibleVersion = r.bits(8)
if compatibleVersion != 0:
return
self.sample_size = r.bits(8)
r.skip(8 + 8 + 8)
self.channels = r.bits(8)
r.skip(16 + 32)
self.bitrate = r.bits(32)
self.sample_rate = r.bits(32)
except BitReaderError as e:
raise ASEntryError(e)
