class __GIF__(ImageMetrics):
HEADER = construct.Struct('header',
construct.Const(construct.String('gif',3),'GIF'),
construct.String('version',3))
SCREEN_DESCRIPTOR = construct.Struct('logical_screen_descriptor',
construct.ULInt16('width'),
construct.ULInt16('height'),
construct.Embed(
construct.BitStruct('packed_fields',
construct.Flag('global_color_table'),
construct.Bits('color_resolution',3),
construct.Flag('sort'),
construct.Bits('global_color_table_size',3))),
construct.Byte('background_color_index'),
construct.Byte('pixel_aspect_ratio'))
def __init__(self, width, height, color_count):
ImageMetrics.__init__(self, width, height, 8, color_count, u'image/gif')
@classmethod
def parse(cls, file):
try:
header = cls.HEADER.parse_stream(file)
descriptor = cls.SCREEN_DESCRIPTOR.parse_stream(file)
return __GIF__(descriptor.width, descriptor.height,
2 ** (descriptor.global_color_table_size + 1))
except construct.ConstError:
raise InvalidGIF(_(u'Invalid GIF'))
def __init__(self, atom_name, sub_atom):
construct.Struct.__init__(self, atom_name)
self.atom_name = atom_name
self.sub_atom = sub_atom
self.header = construct.Struct(
atom_name, construct.UBInt32("size"),
construct.Const(construct.String("type", 4), atom_name))
class __BMP__(ImageMetrics):
HEADER = construct.Struct('bmp_header',
construct.Const(construct.String('magic_number',2),'BM'),
construct.ULInt32('file_size'),
construct.ULInt16('reserved1'),
construct.ULInt16('reserved2'),
construct.ULInt32('bitmap_data_offset'))
INFORMATION = construct.Struct('bmp_information',
construct.ULInt32('header_size'),
construct.ULInt32('width'),
construct.ULInt32('height'),
construct.ULInt16('color_planes'),
construct.ULInt16('bits_per_pixel'),
construct.ULInt32('compression_method'),
construct.ULInt32('image_size'),
construct.ULInt32('horizontal_resolution'),
construct.ULInt32('vertical_resolution'),
construct.ULInt32('colors_used'),
construct.ULInt32('important_colors_used'))
def __init__(self, width, height, bits_per_pixel, color_count):
ImageMetrics.__init__(self, width, height, bits_per_pixel, color_count,
u'image/x-ms-bmp')
@classmethod
def parse(cls, file):
try:
header = cls.HEADER.parse_stream(file)
information = cls.INFORMATION.parse_stream(file)
return __BMP__(information.width, information.height,
information.bits_per_pixel,
information.colors_used)
except construct.ConstError:
raise InvalidBMP(_(u'Invalid BMP'))
class AuAudio(AudioFile):
SUFFIX = "au"
NAME = SUFFIX
AU_HEADER = construct.Struct(
'header', construct.Const(construct.String('magic_number', 4), '.snd'),
construct.UBInt32('data_offset'), construct.UBInt32('data_size'),
construct.UBInt32('encoding_format'), construct.UBInt32('sample_rate'),
construct.UBInt32('channels'))
def __init__(self, filename):
AudioFile.__init__(self, filename)
f = file(filename, 'rb')
try:
header = AuAudio.AU_HEADER.parse_stream(f)
if (header.encoding_format not in (2, 3, 4)):
raise InvalidFile(_(u"Unsupported Sun AU encoding format"))
self.__bits_per_sample__ = {
2: 8,
3: 16,
4: 24
}[header.encoding_format]
self.__channels__ = header.channels
self.__sample_rate__ = header.sample_rate
self.__total_frames__ = header.data_size / \
(self.__bits_per_sample__ / 8) / \
self.__channels__
self.__data_offset__ = header.data_offset
self.__data_size__ = header.data_size
except construct.ConstError:
raise InvalidFile(str(msg))
@classmethod
def is_type(cls, file):
return file.read(4) == ".snd"
def lossless(self):
return True
def bits_per_sample(self):
return self.__bits_per_sample__
def channels(self):
return self.__channels__
def channel_mask(self):
if (self.channels() <= 2):
return ChannelMask.from_channels(self.channels())
else:
return ChannelMask(0)
def sample_rate(self):
return self.__sample_rate__
def total_frames(self):
return self.__total_frames__
def to_pcm(self):
f = file(self.filename, 'rb')
f.seek(self.__data_offset__, 0)
return PCMReader(f,
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(self.channel_mask()),
bits_per_sample=self.bits_per_sample(),
signed=True,
big_endian=True)
@classmethod
def from_pcm(cls, filename, pcmreader, compression=None):
if (pcmreader.bits_per_sample not in (8, 16, 24)):
raise InvalidFormat(
_(u"Unsupported bits per sample %s") %
(pcmreader.bits_per_sample))
bytes_per_sample = pcmreader.bits_per_sample / 8
header = construct.Container(magic_number='.snd',
data_offset=0,
data_size=0,
encoding_format={
8: 2,
16: 3,
24: 4
}[pcmreader.bits_per_sample],
sample_rate=pcmreader.sample_rate,
channels=pcmreader.channels)
try:
f = file(filename, 'wb')
except IOError:
raise EncodingError(None)
try:
#send out a dummy header
f.write(AuAudio.AU_HEADER.build(header))
header.data_offset = f.tell()
#send our big-endian PCM data
#d will be a list of ints, so we can't use transfer_data
framelist = pcmreader.read(BUFFER_SIZE)
while (len(framelist) > 0):
bytes = framelist.to_bytes(True, True)
f.write(bytes)
header.data_size += len(bytes)
framelist = pcmreader.read(BUFFER_SIZE)
#send out a complete header
f.seek(0, 0)
f.write(AuAudio.AU_HEADER.build(header))
finally:
f.close()
try:
pcmreader.close()
except DecodingError:
raise EncodingError()
return AuAudio(filename)
@classmethod
def track_name(cls, file_path, track_metadata=None, format=None):
if (format is None):
format = "track%(track_number)2.2d.au"
return AudioFile.track_name(file_path,
track_metadata,
format,
suffix=cls.SUFFIX)
def Atom(name):
return AtomAdapter(
construct.Struct(name, construct.UBInt32("size"),
construct.String("type", 4),
construct.String("data",
lambda ctx: ctx["size"] - 8)))
header = self.header.parse_stream(stream)
return self.sub_atom.parse_stream(stream)
def _build(self, obj, stream, context):
data = self.sub_atom.build(obj)
stream.write(
self.header.build(
construct.Container(type=self.atom_name, size=len(data) + 8)))
stream.write(data)
def _sizeof(self, context):
return self.sub_atom.sizeof(context) + 8
ATOM_FTYP = construct.Struct(
"ftyp", construct.String("major_brand", 4),
construct.UBInt32("major_brand_version"),
construct.GreedyRepeater(construct.String("compatible_brands", 4)))
ATOM_MVHD = construct.Struct(
"mvhd", construct.Byte("version"), construct.String("flags", 3),
VersionLength("created_mac_UTC_date"),
VersionLength("modified_mac_UTC_date"), construct.UBInt32("time_scale"),
VersionLength("duration"), construct.UBInt32("playback_speed"),
construct.UBInt16("user_volume"), construct.Padding(10),
construct.Struct("windows", construct.UBInt32("geometry_matrix_a"),
construct.UBInt32("geometry_matrix_b"),
construct.UBInt32("geometry_matrix_u"),
construct.UBInt32("geometry_matrix_c"),
construct.UBInt32("geometry_matrix_d"),
construct.UBInt32("geometry_matrix_v"),
class ApeAudio(ApeTaggedAudio, AudioFile):
SUFFIX = "ape"
NAME = SUFFIX
DEFAULT_COMPRESSION = "5000"
COMPRESSION_MODES = tuple([str(x * 1000) for x in range(1, 6)])
del (x)
BINARIES = ("mac", )
FILE_HEAD = construct.Struct("ape_head", construct.String('id', 4),
construct.ULInt16('version'))
#version >= 3.98
APE_DESCRIPTOR = construct.Struct(
"ape_descriptor", construct.ULInt16('padding'),
construct.ULInt32('descriptor_bytes'),
construct.ULInt32('header_bytes'),
construct.ULInt32('seektable_bytes'),
construct.ULInt32('header_data_bytes'),
construct.ULInt32('frame_data_bytes'),
construct.ULInt32('frame_data_bytes_high'),
construct.ULInt32('terminating_data_bytes'),
construct.String('md5', 16))
APE_HEADER = construct.Struct("ape_header",
construct.ULInt16('compression_level'),
construct.ULInt16('format_flags'),
construct.ULInt32('blocks_per_frame'),
construct.ULInt32('final_frame_blocks'),
construct.ULInt32('total_frames'),
construct.ULInt16('bits_per_sample'),
construct.ULInt16('number_of_channels'),
construct.ULInt32('sample_rate'))
#version <= 3.97
APE_HEADER_OLD = construct.Struct("ape_header_old",
construct.ULInt16('compression_level'),
construct.ULInt16('format_flags'),
construct.ULInt16('number_of_channels'),
construct.ULInt32('sample_rate'),
construct.ULInt32('header_bytes'),
construct.ULInt32('terminating_bytes'),
construct.ULInt32('total_frames'),
construct.ULInt32('final_frame_blocks'))
def __init__(self, filename):
AudioFile.__init__(self, filename)
(self.__samplespersec__, self.__channels__, self.__bitspersample__,
self.__totalsamples__) = ApeAudio.__ape_info__(filename)
@classmethod
def is_type(cls, file):
return file.read(4) == "MAC "
def lossless(self):
return True
@classmethod
def supports_foreign_riff_chunks(cls):
return True
def has_foreign_riff_chunks(self):
#FIXME - this isn't strictly true
#I'll need a way to detect foreign chunks in APE's stream
#without decoding it first,
#but since I'm not supporting APE anyway, I'll take the lazy way out
return True
def bits_per_sample(self):
return self.__bitspersample__
def channels(self):
return self.__channels__
def total_frames(self):
return self.__totalsamples__
def sample_rate(self):
return self.__samplespersec__
@classmethod
def __ape_info__(cls, filename):
f = file(filename, 'rb')
try:
file_head = cls.FILE_HEAD.parse_stream(f)
if (file_head.id != 'MAC '):
raise InvalidFile(_(u"Invalid Monkey's Audio header"))
if (file_head.version >= 3980): #the latest APE file type
descriptor = cls.APE_DESCRIPTOR.parse_stream(f)
header = cls.APE_HEADER.parse_stream(f)
return (header.sample_rate,
header.number_of_channels,
header.bits_per_sample,
((header.total_frames - 1) * \
header.blocks_per_frame) + \
header.final_frame_blocks)
else: #old-style APE file (obsolete)
header = cls.APE_HEADER_OLD.parse_stream(f)
if (file_head.version >= 3950):
blocks_per_frame = 0x48000
elif ((file_head.version >= 3900)
or ((file_head.version >= 3800) and
(header.compression_level == 4000))):
blocks_per_frame = 0x12000
else:
blocks_per_frame = 0x2400
if (header.format_flags & 0x01):
bits_per_sample = 8
elif (header.format_flags & 0x08):
bits_per_sample = 24
else:
bits_per_sample = 16
return (header.sample_rate,
header.number_of_channels,
bits_per_sample,
((header.total_frames - 1) * \
blocks_per_frame) + \
header.final_frame_blocks)
finally:
f.close()
def to_wave(self, wave_filename):
if (self.filename.endswith(".ape")):
devnull = file(os.devnull, "wb")
sub = subprocess.Popen(
[BIN['mac'], self.filename, wave_filename, '-d'],
stdout=devnull,
stderr=devnull)
sub.wait()
devnull.close()
else:
devnull = file(os.devnull, 'ab')
import tempfile
ape = tempfile.NamedTemporaryFile(suffix='.ape')
f = file(self.filename, 'rb')
transfer_data(f.read, ape.write)
f.close()
ape.flush()
sub = subprocess.Popen([BIN['mac'], ape.name, wave_filename, '-d'],
stdout=devnull,
stderr=devnull)
sub.wait()
ape.close()
devnull.close()
@classmethod
def from_wave(cls, filename, wave_filename, compression=None):
if (str(compression) not in cls.COMPRESSION_MODES):
compression = cls.DEFAULT_COMPRESSION
devnull = file(os.devnull, "wb")
sub = subprocess.Popen(
[BIN['mac'], wave_filename, filename,
"-c%s" % (compression)],
stdout=devnull,
stderr=devnull)
sub.wait()
devnull.close()
return ApeAudio(filename)
class ApeTag(MetaData):
ITEM = ApeTagItem
APEv2_FLAGS = construct.BitStruct("APEv2_FLAGS",
construct.Bits("undefined1", 5),
construct.Flag("read_only"),
construct.Bits("encoding", 2),
construct.Bits("undefined2", 16),
construct.Flag("contains_header"),
construct.Flag("contains_no_footer"),
construct.Flag("is_header"),
construct.Bits("undefined3", 5))
APEv2_FOOTER = construct.Struct("APEv2", construct.String("preamble", 8),
construct.ULInt32("version_number"),
construct.ULInt32("tag_size"),
construct.ULInt32("item_count"),
construct.Embed(APEv2_FLAGS),
construct.ULInt64("reserved"))
APEv2_HEADER = APEv2_FOOTER
APEv2_TAG = ApeTagItem.APEv2_TAG
ATTRIBUTE_MAP = {
'track_name': 'Title',
'track_number': 'Track',
'track_total': 'Track',
'album_number': 'Media',
'album_total': 'Media',
'album_name': 'Album',
'artist_name': 'Artist',
#"Performer" is not a defined APEv2 key
#it would be nice to have, yet would not be standard
'performer_name': 'Performer',
'composer_name': 'Composer',
'conductor_name': 'Conductor',
'ISRC': 'ISRC',
'catalog': 'Catalog',
'copyright': 'Copyright',
'publisher': 'Publisher',
'year': 'Year',
'date': 'Record Date',
'comment': 'Comment'
}
INTEGER_ITEMS = ('Track', 'Media')
#tags is a list of ApeTagItem objects
#tag_length is an optional total length integer
def __init__(self, tags, tag_length=None):
for tag in tags:
if (not isinstance(tag, ApeTagItem)):
raise ValueError("%s is not ApeTag" % (repr(tag)))
self.__dict__["tags"] = tags
self.__dict__["tag_length"] = tag_length
def __eq__(self, metadata):
if (isinstance(metadata, ApeTag)):
if (set(self.keys()) != set(metadata.keys())):
return False
for tag in self.tags:
try:
if (tag.data != metadata[tag.key].data):
return False
except KeyError:
return False
else:
return True
elif (isinstance(metadata, MetaData)):
return MetaData.__eq__(self, metadata)
else:
return False
def keys(self):
return [tag.key for tag in self.tags]
def __getitem__(self, key):
for tag in self.tags:
if (tag.key == key):
return tag
else:
raise KeyError(key)
def get(self, key, default):
try:
return self[key]
except KeyError:
return default
def __setitem__(self, key, value):
for i in xrange(len(self.tags)):
if (self.tags[i].key == key):
self.tags[i] = value
return
else:
self.tags.append(value)
def index(self, key):
for (i, tag) in enumerate(self.tags):
if (tag.key == key):
return i
else:
raise ValueError(key)
def __delitem__(self, key):
for i in xrange(len(self.tags)):
if (self.tags[i].key == key):
del (self.tags[i])
return
#if an attribute is updated (e.g. self.track_name)
#make sure to update the corresponding dict pair
def __setattr__(self, key, value):
if (key in self.ATTRIBUTE_MAP):
if (key == 'track_number'):
self['Track'] = self.ITEM.string(
'Track', __number_pair__(value, self.track_total))
elif (key == 'track_total'):
self['Track'] = self.ITEM.string(
'Track', __number_pair__(self.track_number, value))
elif (key == 'album_number'):
self['Media'] = self.ITEM.string(
'Media', __number_pair__(value, self.album_total))
elif (key == 'album_total'):
self['Media'] = self.ITEM.string(
'Media', __number_pair__(self.album_number, value))
else:
self[self.ATTRIBUTE_MAP[key]] = self.ITEM.string(
self.ATTRIBUTE_MAP[key], value)
else:
self.__dict__[key] = value
def __getattr__(self, key):
if (key == 'track_number'):
try:
return int(
re.findall('\d+', unicode(self.get("Track", u"0")))[0])
except IndexError:
return 0
elif (key == 'track_total'):
try:
return int(
re.findall('\d+/(\d+)', unicode(self.get("Track",
u"0")))[0])
except IndexError:
return 0
elif (key == 'album_number'):
try:
return int(
re.findall('\d+', unicode(self.get("Media", u"0")))[0])
except IndexError:
return 0
elif (key == 'album_total'):
try:
return int(
re.findall('\d+/(\d+)', unicode(self.get("Media",
u"0")))[0])
except IndexError:
return 0
elif (key in self.ATTRIBUTE_MAP):
return unicode(self.get(self.ATTRIBUTE_MAP[key], u''))
elif (key in MetaData.__FIELDS__):
return u''
else:
try:
return self.__dict__[key]
except KeyError:
raise AttributeError(key)
def __delattr__(self, key):
if (key == 'track_number'):
setattr(self, 'track_number', 0)
if ((self.track_number == 0) and (self.track_total == 0)):
del (self['Track'])
elif (key == 'track_total'):
setattr(self, 'track_total', 0)
if ((self.track_number == 0) and (self.track_total == 0)):
del (self['Track'])
elif (key == 'album_number'):
setattr(self, 'album_number', 0)
if ((self.album_number == 0) and (self.album_total == 0)):
del (self['Media'])
elif (key == 'album_total'):
setattr(self, 'album_total', 0)
if ((self.album_number == 0) and (self.album_total == 0)):
del (self['Media'])
elif (key in self.ATTRIBUTE_MAP):
try:
del (self[self.ATTRIBUTE_MAP[key]])
except ValueError:
pass
elif (key in MetaData.__FIELDS__):
pass
else:
try:
del (self.__dict__[key])
except KeyError:
raise AttributeError(key)
@classmethod
def converted(cls, metadata):
if ((metadata is None) or (isinstance(metadata, ApeTag))):
return metadata
else:
tags = cls([])
for (field, key) in cls.ATTRIBUTE_MAP.items():
if (field not in cls.__INTEGER_FIELDS__):
field = unicode(getattr(metadata, field))
if (len(field) > 0):
tags[key] = cls.ITEM.string(key, field)
if ((metadata.track_number != 0) or (metadata.track_total != 0)):
tags["Track"] = cls.ITEM.string(
"Track",
__number_pair__(metadata.track_number,
metadata.track_total))
if ((metadata.album_number != 0) or (metadata.album_total != 0)):
tags["Media"] = cls.ITEM.string(
"Media",
__number_pair__(metadata.album_number,
metadata.album_total))
for image in metadata.images():
tags.add_image(image)
return tags
def merge(self, metadata):
metadata = self.__class__.converted(metadata)
if (metadata is None):
return
for tag in metadata.tags:
if ((tag.key not in ('Track', 'Media')) and (len(str(tag)) > 0)
and (len(str(self.get(tag.key, ""))) == 0)):
self[tag.key] = tag
for attr in ("track_number", "track_total", "album_number",
"album_total"):
if ((getattr(self, attr) == 0) and (getattr(metadata, attr) != 0)):
setattr(self, attr, getattr(metadata, attr))
def __comment_name__(self):
return u'APEv2'
#takes two (key,value) apetag pairs
#returns cmp on the weighted set of them
#(title first, then artist, album, tracknumber)
@classmethod
def __by_pair__(cls, pair1, pair2):
KEY_MAP = {
"Title": 1,
"Album": 2,
"Track": 3,
"Media": 4,
"Artist": 5,
"Performer": 6,
"Composer": 7,
"Conductor": 8,
"Catalog": 9,
"Publisher": 10,
"ISRC": 11,
#"Media":12,
"Year": 13,
"Record Date": 14,
"Copyright": 15
}
return cmp((KEY_MAP.get(pair1[0], 16), pair1[0], pair1[1]),
(KEY_MAP.get(pair2[0], 16), pair2[0], pair2[1]))
def __comment_pairs__(self):
items = []
for tag in self.tags:
if (tag.key in ('Cover Art (front)', 'Cover Art (back)')):
pass
elif (tag.type == 0):
items.append((tag.key, unicode(tag)))
else:
if (len(str(tag)) <= 20):
items.append((tag.key, str(tag).encode('hex')))
else:
items.append(
(tag.key,
str(tag).encode('hex')[0:39].upper() + u"\u2026"))
return sorted(items, ApeTag.__by_pair__)
@classmethod
def supports_images(cls):
return True
def __parse_image__(self, key, type):
data = cStringIO.StringIO(str(self[key]))
description = construct.CString(None).parse_stream(data).decode(
'utf-8', 'replace')
data = data.read()
return Image.new(data, description, type)
def add_image(self, image):
if (image.type == 0):
self['Cover Art (front)'] = self.ITEM.external(
'Cover Art (front)',
construct.CString(None).build(
image.description.encode('utf-8', 'replace')) + image.data)
elif (image.type == 1):
self['Cover Art (back)'] = self.ITEM.binary(
'Cover Art (back)',
construct.CString(None).build(
image.description.encode('utf-8', 'replace')) + image.data)
def delete_image(self, image):
if ((image.type == 0) and 'Cover Art (front)' in self.keys()):
del (self['Cover Art (front)'])
elif ((image.type == 1) and 'Cover Art (back)' in self.keys()):
del (self['Cover Art (back)'])
def images(self):
#APEv2 supports only one value per key
#so a single front and back cover are all that is possible
img = []
if ('Cover Art (front)' in self.keys()):
img.append(self.__parse_image__('Cover Art (front)', 0))
if ('Cover Art (back)' in self.keys()):
img.append(self.__parse_image__('Cover Art (back)', 1))
return img
#takes a file object of a APEv2 tagged file
#returns an ApeTag object or None
@classmethod
def read(cls, apefile):
apefile.seek(-32, 2)
footer = cls.APEv2_FOOTER.parse(apefile.read(32))
if (footer.preamble != 'APETAGEX'):
return None
apefile.seek(-(footer.tag_size), 2)
return cls([
ApeTagItem(item_type=tag.encoding,
read_only=tag.read_only,
key=tag.key,
data=tag.value)
for tag in construct.StrictRepeater(
footer.item_count, cls.APEv2_TAG).parse(apefile.read())
],
tag_length=footer.tag_size + ApeTag.APEv2_FOOTER.sizeof()
if footer.contains_header else footer.tag_size)
def build(self):
header = construct.Container(preamble='APETAGEX',
version_number=2000,
tag_size=0,
item_count=len(self.tags),
undefined1=0,
undefined2=0,
undefined3=0,
read_only=False,
encoding=0,
contains_header=True,
contains_no_footer=False,
is_header=True,
reserved=0l)
footer = construct.Container(preamble=header.preamble,
version_number=header.version_number,
tag_size=0,
item_count=len(self.tags),
undefined1=0,
undefined2=0,
undefined3=0,
read_only=False,
encoding=0,
contains_header=True,
contains_no_footer=False,
is_header=False,
reserved=0l)
tags = "".join([tag.build() for tag in self.tags])
footer.tag_size = header.tag_size = \
len(tags) + len(ApeTag.APEv2_FOOTER.build(footer))
return ApeTag.APEv2_FOOTER.build(header) + \
tags + \
ApeTag.APEv2_FOOTER.build(footer)
class OggStreamReader:
OGGS = construct.Struct(
"oggs", construct.Const(construct.String("magic_number", 4), "OggS"),
construct.Byte("version"), construct.Byte("header_type"),
construct.SLInt64("granule_position"),
construct.ULInt32("bitstream_serial_number"),
construct.ULInt32("page_sequence_number"),
construct.ULInt32("checksum"), construct.Byte("segments"),
construct.MetaRepeater(lambda ctx: ctx["segments"],
construct.Byte("segment_lengths")))
#stream is a file-like object with read() and close() methods
def __init__(self, stream):
self.stream = stream
def close(self):
self.stream.close()
#an iterator which yields one fully-reassembled Ogg packet per pass
def packets(self, from_beginning=True):
if (from_beginning):
self.stream.seek(0, 0)
segment = cStringIO.StringIO()
while (True):
try:
page = OggStreamReader.OGGS.parse_stream(self.stream)
for length in page.segment_lengths:
if (length == 255):
segment.write(self.stream.read(length))
else:
segment.write(self.stream.read(length))
yield segment.getvalue()
segment = cStringIO.StringIO()
except construct.core.FieldError:
break
except construct.ConstError:
break
#an iterator which yields (Container,data string) tuples per pass
#Container is parsed from OGGS
#data string is a collection of segments as a string
#(it may not be a complete packet)
def pages(self, from_beginning=True):
if (from_beginning):
self.stream.seek(0, 0)
while (True):
try:
page = OggStreamReader.OGGS.parse_stream(self.stream)
yield (page, self.stream.read(sum(page.segment_lengths)))
except construct.core.FieldError:
break
except construct.ConstError:
break
#takes a page iterator (such as pages(), above)
#returns a list of (Container,data string) tuples
#which form a complete packet
@classmethod
def pages_to_packet(cls, pages_iter):
packet = [pages_iter.next()]
while (packet[-1][0].segment_lengths[-1] == 255):
packet.append(pages_iter.next())
return packet
CRC_LOOKUP = (
0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7,
0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3,
0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef,
0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb,
0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4,
0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08,
0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc,
0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050,
0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1,
0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5,
0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9,
0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd,
0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2,
0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e,
0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a,
0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676,
0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4)
#page_header is a Container object parsed through OGGS, above
#page_data is a string of data contained by the page
#returns an integer of the page's checksum
@classmethod
def calculate_ogg_checksum(cls, page_header, page_data):
old_checksum = page_header.checksum
try:
page_header.checksum = 0
sum = 0
for c in cls.OGGS.build(page_header) + page_data:
sum = ((sum << 8) ^ \
cls.CRC_LOOKUP[((sum >> 24) & 0xFF)^ ord(c)]) \
& 0xFFFFFFFF
return sum
finally:
page_header.checksum = old_checksum
class VorbisAudio(AudioFile):
SUFFIX = "ogg"
NAME = SUFFIX
DEFAULT_COMPRESSION = "3"
COMPRESSION_MODES = tuple([str(i) for i in range(0, 11)])
BINARIES = ("oggenc", "oggdec")
OGG_IDENTIFICATION = construct.Struct(
"ogg_id", construct.ULInt32("vorbis_version"),
construct.Byte("channels"), construct.ULInt32("sample_rate"),
construct.ULInt32("bitrate_maximum"),
construct.ULInt32("bitrate_nominal"),
construct.ULInt32("bitrate_minimum"),
construct.Embed(
construct.BitStruct("flags", construct.Bits("blocksize_0", 4),
construct.Bits("blocksize_1", 4))),
construct.Byte("framing"))
COMMENT_HEADER = construct.Struct("comment_header",
construct.Byte("packet_type"),
construct.String("vorbis", 6))
def __init__(self, filename):
AudioFile.__init__(self, filename)
self.__read_metadata__()
@classmethod
def is_type(cls, file):
header = file.read(0x23)
return (header.startswith('OggS')
and header[0x1C:0x23] == '\x01vorbis')
def __read_metadata__(self):
f = OggStreamReader(file(self.filename, "rb"))
packets = f.packets()
try:
#we'll assume this Vorbis file isn't interleaved
#with any other Ogg stream
#the Identification packet comes first
id_packet = packets.next()
header = VorbisAudio.COMMENT_HEADER.parse(
id_packet[0:VorbisAudio.COMMENT_HEADER.sizeof()])
if ((header.packet_type == 0x01) and (header.vorbis == 'vorbis')):
identification = VorbisAudio.OGG_IDENTIFICATION.parse(
id_packet[VorbisAudio.COMMENT_HEADER.sizeof():])
self.__sample_rate__ = identification.sample_rate
self.__channels__ = identification.channels
else:
raise InvalidFile(_(u'First packet is not Vorbis'))
#the Comment packet comes next
comment_packet = packets.next()
header = VorbisAudio.COMMENT_HEADER.parse(
comment_packet[0:VorbisAudio.COMMENT_HEADER.sizeof()])
if ((header.packet_type == 0x03) and (header.vorbis == 'vorbis')):
self.comment = VorbisComment.VORBIS_COMMENT.parse(
comment_packet[VorbisAudio.COMMENT_HEADER.sizeof():])
finally:
del (packets)
f.close()
del (f)
def lossless(self):
return False
def bits_per_sample(self):
return 16
def channels(self):
return self.__channels__
def channel_mask(self):
if (self.channels() == 1):
return ChannelMask.from_fields(front_center=True)
elif (self.channels() == 2):
return ChannelMask.from_fields(front_left=True, front_right=True)
elif (self.channels() == 3):
return ChannelMask.from_fields(front_left=True,
front_right=True,
front_center=True)
elif (self.channels() == 4):
return ChannelMask.from_fields(front_left=True,
front_right=True,
back_left=True,
back_right=True)
elif (self.channels() == 5):
return ChannelMask.from_fields(front_left=True,
front_right=True,
front_center=True,
back_left=True,
back_right=True)
elif (self.channels() == 6):
return ChannelMask.from_fields(front_left=True,
front_right=True,
front_center=True,
back_left=True,
back_right=True,
low_frequency=True)
elif (self.channels() == 7):
return ChannelMask.from_fields(front_left=True,
front_right=True,
front_center=True,
side_left=True,
side_right=True,
back_center=True,
low_frequency=True)
elif (self.channels() == 8):
return ChannelMask.from_fields(front_left=True,
front_right=True,
side_left=True,
side_right=True,
back_left=True,
back_right=True,
front_center=True,
low_frequency=True)
else:
return ChannelMask(0)
def total_frames(self):
pcm_samples = 0
f = file(self.filename, "rb")
try:
while (True):
try:
page = OggStreamReader.OGGS.parse_stream(f)
pcm_samples = page.granule_position
f.seek(sum(page.segment_lengths), 1)
except construct.core.FieldError:
break
except construct.ConstError:
break
return pcm_samples
finally:
f.close()
def sample_rate(self):
return self.__sample_rate__
def to_pcm(self):
sub = subprocess.Popen([
BIN['oggdec'], '-Q', '-b',
str(16), '-e',
str(0), '-s',
str(1), '-R', '-o', '-', self.filename
],
stdout=subprocess.PIPE,
stderr=file(os.devnull, "a"))
pcmreader = PCMReader(sub.stdout,
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(self.channel_mask()),
bits_per_sample=self.bits_per_sample(),
process=sub)
if (self.channels() <= 2):
return pcmreader
elif (self.channels() <= 8):
#these mappings transform Vorbis order into ChannelMask order
standard_channel_mask = self.channel_mask()
vorbis_channel_mask = VorbisChannelMask(self.channel_mask())
return ReorderedPCMReader(pcmreader, [
vorbis_channel_mask.channels().index(channel)
for channel in standard_channel_mask.channels()
])
else:
return pcmreader
@classmethod
def from_pcm(cls, filename, pcmreader, compression=None):
if (compression not in cls.COMPRESSION_MODES):
compression = cls.DEFAULT_COMPRESSION
devnull = file(os.devnull, 'ab')
sub = subprocess.Popen([
BIN['oggenc'], '-Q', '-r', '-B',
str(pcmreader.bits_per_sample), '-C',
str(pcmreader.channels), '-R',
str(pcmreader.sample_rate), '--raw-endianness',
str(0), '-q', compression, '-o', filename, '-'
],
stdin=subprocess.PIPE,
stdout=devnull,
stderr=devnull,
preexec_fn=ignore_sigint)
if ((pcmreader.channels <= 2) or (int(pcmreader.channel_mask) == 0)):
transfer_framelist_data(pcmreader, sub.stdin.write)
elif (pcmreader.channels <= 8):
if (int(pcmreader.channel_mask) in (
0x7, #FR, FC, FL
0x33, #FR, FL, BR, BL
0x37, #FR, FC, FL, BL, BR
0x3f, #FR, FC, FL, BL, BR, LFE
0x70f, #FL, FC, FR, SL, SR, BC, LFE
0x63f) #FL, FC, FR, SL, SR, BL, BR, LFE
):
standard_channel_mask = ChannelMask(pcmreader.channel_mask)
vorbis_channel_mask = VorbisChannelMask(standard_channel_mask)
else:
raise UnsupportedChannelMask()
transfer_framelist_data(
ReorderedPCMReader(pcmreader, [
standard_channel_mask.channels().index(channel)
for channel in vorbis_channel_mask.channels()
]), sub.stdin.write)
else:
raise UnsupportedChannelMask()
try:
pcmreader.close()
except DecodingError:
raise EncodingError()
sub.stdin.close()
devnull.close()
if (sub.wait() == 0):
return VorbisAudio(filename)
else:
raise EncodingError(BIN['oggenc'])
def set_metadata(self, metadata):
metadata = VorbisComment.converted(metadata)
if (metadata is None): return
reader = OggStreamReader(file(self.filename, 'rb'))
new_file = cStringIO.StringIO()
writer = OggStreamWriter(new_file)
current_sequence_number = 0
pages = reader.pages()
#transfer our old header
#this must always be the first packet and the first page
(header_page, header_data) = pages.next()
writer.write_page(header_page, header_data)
current_sequence_number += 1
#grab the current "comment" and "setup headers" packets
#these may take one or more pages,
#but will always end on a page boundary
del (pages)
packets = reader.packets(from_beginning=False)
comment_packet = packets.next()
headers_packet = packets.next()
#write the pages for our new "comment" packet
for (page, data) in OggStreamWriter.build_pages(
0, header_page.bitstream_serial_number,
current_sequence_number,
VorbisAudio.COMMENT_HEADER.build(
construct.Container(packet_type=3, vorbis='vorbis')) +
metadata.build()):
writer.write_page(page, data)
current_sequence_number += 1
#write the pages for the old "setup headers" packet
for (page, data) in OggStreamWriter.build_pages(
0, header_page.bitstream_serial_number,
current_sequence_number, headers_packet):
writer.write_page(page, data)
current_sequence_number += 1
#write the rest of the pages, re-sequenced and re-checksummed
del (packets)
pages = reader.pages(from_beginning=False)
for (i, (page, data)) in enumerate(pages):
page.page_sequence_number = i + current_sequence_number
page.checksum = OggStreamReader.calculate_ogg_checksum(page, data)
writer.write_page(page, data)
reader.close()
#re-write the file with our new data in "new_file"
f = file(self.filename, "wb")
f.write(new_file.getvalue())
f.close()
writer.close()
self.__read_metadata__()
def get_metadata(self):
self.__read_metadata__()
data = {}
for pair in self.comment.value:
try:
(key, value) = pair.split('=', 1)
data.setdefault(key, []).append(value.decode('utf-8'))
except ValueError:
continue
return VorbisComment(data)
def delete_metadata(self):
self.set_metadata(MetaData())
@classmethod
def add_replay_gain(cls, filenames):
track_names = [
track.filename for track in open_files(filenames)
if isinstance(track, cls)
]
if ((len(track_names) > 0) and BIN.can_execute(BIN['vorbisgain'])):
devnull = file(os.devnull, 'ab')
sub = subprocess.Popen([BIN['vorbisgain'], '-q', '-a'] +
track_names,
stdout=devnull,
stderr=devnull)
sub.wait()
devnull.close()
@classmethod
def can_add_replay_gain(cls):
return BIN.can_execute(BIN['vorbisgain'])
@classmethod
def lossless_replay_gain(cls):
return True
def replay_gain(self):
vorbis_metadata = self.get_metadata()
if (set([
'REPLAYGAIN_TRACK_PEAK', 'REPLAYGAIN_TRACK_GAIN',
'REPLAYGAIN_ALBUM_PEAK', 'REPLAYGAIN_ALBUM_GAIN'
]).issubset(vorbis_metadata.keys())): #we have ReplayGain data
try:
return ReplayGain(
vorbis_metadata['REPLAYGAIN_TRACK_GAIN'][0][0:-len(" dB")],
vorbis_metadata['REPLAYGAIN_TRACK_PEAK'][0],
vorbis_metadata['REPLAYGAIN_ALBUM_GAIN'][0][0:-len(" dB")],
vorbis_metadata['REPLAYGAIN_ALBUM_PEAK'][0])
except ValueError:
return None
else:
return None
class ID3v1Comment(MetaData, list):
ID3v1 = construct.Struct(
"id3v1", construct.Const(construct.String("identifier", 3), 'TAG'),
construct.String("song_title", 30), construct.String("artist", 30),
construct.String("album", 30), construct.String("year", 4),
construct.String("comment", 28), construct.Padding(1),
construct.Byte("track_number"), construct.Byte("genre"))
ID3v1_NO_TRACKNUMBER = construct.Struct(
"id3v1_notracknumber",
construct.Const(construct.String("identifier", 3), 'TAG'),
construct.String("song_title", 30), construct.String("artist", 30),
construct.String("album", 30), construct.String("year", 4),
construct.String("comment", 30), construct.Byte("genre"))
ATTRIBUTES = [
'track_name', 'artist_name', 'album_name', 'year', 'comment',
'track_number'
]
#takes an MP3 filename
#returns a (song title, artist, album, year, comment, track number) tuple
#if no ID3v1 tag is present, returns a tuple with those fields blank
#all text is in unicode
#if track number is -1, the id3v1 comment could not be found
@classmethod
def read_id3v1_comment(cls, mp3filename):
mp3file = file(mp3filename, "rb")
try:
mp3file.seek(-128, 2)
try:
id3v1 = ID3v1Comment.ID3v1.parse(mp3file.read())
except construct.adapters.PaddingError:
mp3file.seek(-128, 2)
id3v1 = ID3v1Comment.ID3v1_NO_TRACKNUMBER.parse(mp3file.read())
id3v1.track_number = 0
except construct.ConstError:
return tuple([u""] * 5 + [-1])
field_list = (id3v1.song_title, id3v1.artist, id3v1.album,
id3v1.year, id3v1.comment)
return tuple(
map(lambda t: t.rstrip('\x00').decode('ascii', 'replace'),
field_list) + [id3v1.track_number])
finally:
mp3file.close()
#takes several unicode strings (except for track_number, an int)
#pads them with nulls and returns a complete ID3v1 tag
@classmethod
def build_id3v1(cls, song_title, artist, album, year, comment,
track_number):
def __s_pad__(s, length):
if (len(s) < length):
return s + chr(0) * (length - len(s))
else:
s = s[0:length].rstrip()
return s + chr(0) * (length - len(s))
c = construct.Container()
c.identifier = 'TAG'
c.song_title = __s_pad__(song_title.encode('ascii', 'replace'), 30)
c.artist = __s_pad__(artist.encode('ascii', 'replace'), 30)
c.album = __s_pad__(album.encode('ascii', 'replace'), 30)
c.year = __s_pad__(year.encode('ascii', 'replace'), 4)
c.comment = __s_pad__(comment.encode('ascii', 'replace'), 28)
c.track_number = int(track_number)
c.genre = 0
return ID3v1Comment.ID3v1.build(c)
#metadata is the title,artist,album,year,comment,tracknum tuple returned by
#read_id3v1_comment
def __init__(self, metadata):
list.__init__(self, metadata)
def supports_images(self):
return False
#if an attribute is updated (e.g. self.track_name)
#make sure to update the corresponding list item
def __setattr__(self, key, value):
if (key in self.ATTRIBUTES):
if (key != 'track_number'):
self[self.ATTRIBUTES.index(key)] = value
else:
self[self.ATTRIBUTES.index(key)] = int(value)
elif (key in MetaData.__FIELDS__):
pass
else:
self.__dict__[key] = value
def __delattr__(self, key):
if (key == 'track_number'):
setattr(self, key, 0)
elif (key in self.ATTRIBUTES):
setattr(self, key, u"")
def __getattr__(self, key):
if (key in self.ATTRIBUTES):
return self[self.ATTRIBUTES.index(key)]
elif (key in MetaData.__INTEGER_FIELDS__):
return 0
elif (key in MetaData.__FIELDS__):
return u""
else:
raise AttributeError(key)
@classmethod
def converted(cls, metadata):
if ((metadata is None) or (isinstance(metadata, ID3v1Comment))):
return metadata
return ID3v1Comment(
(metadata.track_name, metadata.artist_name, metadata.album_name,
metadata.year, metadata.comment, int(metadata.track_number)))
def __comment_name__(self):
return u'ID3v1'
def __comment_pairs__(self):
return zip(('Title', 'Artist', 'Album', 'Year', 'Comment', 'Tracknum'),
self)
def build_tag(self):
return self.build_id3v1(self.track_name, self.artist_name,
self.album_name, self.year, self.comment,
self.track_number)
def images(self):
return []
class SpeexAudio(VorbisAudio):
SUFFIX = "spx"
NAME = SUFFIX
DEFAULT_COMPRESSION = "8"
COMPRESSION_MODES = tuple([str(i) for i in range(0,11)])
BINARIES = ("speexenc","speexdec")
SPEEX_HEADER = construct.Struct('speex_header',
construct.String('speex_string',8),
construct.String('speex_version',20),
construct.ULInt32('speex_version_id'),
construct.ULInt32('header_size'),
construct.ULInt32('sampling_rate'),
construct.ULInt32('mode'),
construct.ULInt32('mode_bitstream_version'),
construct.ULInt32('channels'),
construct.ULInt32('bitrate'),
construct.ULInt32('frame_size'),
construct.ULInt32('vbr'),
construct.ULInt32('frame_per_packet'),
construct.ULInt32('extra_headers'),
construct.ULInt32('reserved1'),
construct.ULInt32('reserved2'))
def __init__(self, filename):
AudioFile.__init__(self, filename)
self.__read_metadata__()
@classmethod
def is_type(cls, file):
header = file.read(0x23)
return (header.startswith('OggS') and
header[0x1C:0x23] == 'Speex ')
def __read_metadata__(self):
f = OggStreamReader(file(self.filename,"rb"))
packets = f.packets()
try:
#first read the Header packet
header = SpeexAudio.SPEEX_HEADER.parse(packets.next())
self.__sample_rate__ = header.sampling_rate
self.__channels__ = header.channels
#the read the Comment packet
comment_packet = packets.next()
self.comment = UnframedVorbisComment.VORBIS_COMMENT.parse(
comment_packet)
finally:
del(packets); f.close(); del(f)
def to_pcm(self):
devnull = file(os.devnull,'ab')
sub = subprocess.Popen([BIN['speexdec'],self.filename,'-'],
stdout=subprocess.PIPE,
stderr=devnull)
return PCMReader(
sub.stdout,
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(ChannelMask.from_channels(self.channels())),
bits_per_sample=self.bits_per_sample(),
process=sub)
@classmethod
def from_pcm(cls, filename, pcmreader, compression=None):
import bisect
if (compression not in cls.COMPRESSION_MODES):
compression = cls.DEFAULT_COMPRESSION
if ((pcmreader.bits_per_sample not in (8,16)) or
(pcmreader.channels > 2) or
(pcmreader.sample_rate not in (8000,16000,32000,44100))):
pcmreader = PCMConverter(
pcmreader,
sample_rate=[8000,8000,16000,32000,44100][bisect.bisect(
[8000,16000,32000,44100],pcmreader.sample_rate)],
channels=min(pcmreader.channels,2),
channel_mask=ChannelMask.from_channels(min(pcmreader.channels,2)),
bits_per_sample=min(pcmreader.bits_per_sample,16))
BITS_PER_SAMPLE = {8:['--8bit'],
16:['--16bit']}[pcmreader.bits_per_sample]
CHANNELS = {1:[],2:['--stereo']}[pcmreader.channels]
devnull = file(os.devnull,"ab")
sub = subprocess.Popen([BIN['speexenc'],
'--quality',str(compression),
'--rate',str(pcmreader.sample_rate),
'--le'] + \
BITS_PER_SAMPLE + \
CHANNELS + \
['-',filename],
stdin=subprocess.PIPE,
stderr=devnull,
preexec_fn=ignore_sigint)
transfer_framelist_data(pcmreader,sub.stdin.write)
try:
pcmreader.close()
except DecodingError:
raise EncodingError()
sub.stdin.close()
result = sub.wait()
devnull.close()
if (result == 0):
return SpeexAudio(filename)
else:
raise EncodingError(BIN['speexenc'])
def set_metadata(self, metadata):
comment = VorbisComment.converted(metadata)
if (comment is None): return
reader = OggStreamReader(file(self.filename,'rb'))
new_file = cStringIO.StringIO()
writer = OggStreamWriter(new_file)
pages = reader.pages()
#transfer our old header
(header_page,header_data) = pages.next()
writer.write_page(header_page,header_data)
#skip the existing comment packet
(page,data) = pages.next()
while (page.segment_lengths[-1] == 255):
(page,data) = pages.next()
#write the pages for our new comment packet
comment_pages = OggStreamWriter.build_pages(
0,
header_page.bitstream_serial_number,
header_page.page_sequence_number + 1,
comment.build())
for (page,data) in comment_pages:
writer.write_page(page,data)
#write the rest of the pages, re-sequenced and re-checksummed
sequence_number = comment_pages[-1][0].page_sequence_number + 1
for (i,(page,data)) in enumerate(pages):
page.page_sequence_number = i + sequence_number
page.checksum = OggStreamReader.calculate_ogg_checksum(page,data)
writer.write_page(page,data)
reader.close()
#re-write the file with our new data in "new_file"
f = file(self.filename,"wb")
f.write(new_file.getvalue())
f.close()
writer.close()
self.__read_metadata__()
@classmethod
def can_add_replay_gain(cls):
return False
class WavPackAudio(ApeTaggedAudio, AudioFile):
SUFFIX = "wv"
NAME = SUFFIX
DEFAULT_COMPRESSION = "veryhigh"
COMPRESSION_MODES = ("fast", "standard", "high", "veryhigh")
BINARIES = ("wavpack", "wvunpack")
APE_TAG_CLASS = WavePackAPEv2
HEADER = construct.Struct(
"wavpackheader", construct.Const(construct.String("id", 4), 'wvpk'),
construct.ULInt32("block_size"), construct.ULInt16("version"),
construct.ULInt8("track_number"), construct.ULInt8("index_number"),
construct.ULInt32("total_samples"), construct.ULInt32("block_index"),
construct.ULInt32("block_samples"),
construct.Embed(
construct.BitStruct("flags", construct.Flag("floating_point_data"),
construct.Flag("hybrid_noise_shaping"),
construct.Flag("cross_channel_decorrelation"),
construct.Flag("joint_stereo"),
construct.Flag("hybrid_mode"),
construct.Flag("mono_output"),
construct.Bits("bits_per_sample", 2),
construct.Bits("left_shift_data_low", 3),
construct.Flag("final_block_in_sequence"),
construct.Flag("initial_block_in_sequence"),
construct.Flag("hybrid_noise_balanced"),
construct.Flag("hybrid_mode_control_bitrate"),
construct.Flag("extended_size_integers"),
construct.Bit("sampling_rate_low"),
construct.Bits("maximum_magnitude", 5),
construct.Bits("left_shift_data_high", 2),
construct.Flag("reserved2"),
construct.Flag("false_stereo"),
construct.Flag("use_IIR"),
construct.Bits("reserved1", 2),
construct.Bits("sampling_rate_high", 3))),
construct.ULInt32("crc"))
SUB_HEADER = construct.Struct(
"wavpacksubheader",
construct.Embed(
construct.BitStruct("flags", construct.Flag("large_block"),
construct.Flag("actual_size_1_less"),
construct.Flag("nondecoder_data"),
construct.Bits("metadata_function", 5))),
construct.IfThenElse('size', lambda ctx: ctx['large_block'],
ULInt24('s'), construct.Byte('s')))
BITS_PER_SAMPLE = (8, 16, 24, 32)
SAMPLING_RATE = (6000, 8000, 9600, 11025, 12000, 16000, 22050, 24000,
32000, 44100, 48000, 64000, 88200, 96000, 192000, 0)
def __init__(self, filename):
self.filename = filename
self.__samplerate__ = 0
self.__channels__ = 0
self.__bitspersample__ = 0
self.__total_frames__ = 0
self.__read_info__()
@classmethod
def is_type(cls, file):
return file.read(4) == 'wvpk'
def lossless(self):
return True
@classmethod
def supports_foreign_riff_chunks(cls):
return True
def channel_mask(self):
fmt_chunk = WaveAudio.FMT_CHUNK.parse(self.__fmt_chunk__())
if (fmt_chunk.compression != 0xFFFE):
if (self.__channels__ == 1):
return ChannelMask.from_fields(front_center=True)
elif (self.__channels__ == 2):
return ChannelMask.from_fields(front_left=True,
front_right=True)
#if we have a multi-channel WavPack file
#that's not WAVEFORMATEXTENSIBLE,
#assume the channels follow SMPTE/ITU-R recommendations
#and hope for the best
elif (self.__channels__ == 3):
return ChannelMask.from_fields(front_left=True,
front_right=True,
front_center=True)
elif (self.__channels__ == 4):
return ChannelMask.from_fields(front_left=True,
front_right=True,
back_left=True,
back_right=True)
elif (self.__channels__ == 5):
return ChannelMask.from_fields(front_left=True,
front_right=True,
back_left=True,
back_right=True,
front_center=True)
elif (self.__channels__ == 6):
return ChannelMask.from_fields(front_left=True,
front_right=True,
back_left=True,
back_right=True,
front_center=True,
low_frequency=True)
else:
return ChannelMask(0)
else:
return WaveAudio.fmt_chunk_to_channel_mask(fmt_chunk.channel_mask)
def get_metadata(self):
metadata = ApeTaggedAudio.get_metadata(self)
if (metadata is not None):
metadata.frame_count = self.total_frames()
return metadata
def has_foreign_riff_chunks(self):
for (sub_header, nondecoder, data) in self.sub_frames():
if ((sub_header == 1) and nondecoder):
return set(__riff_chunk_ids__(data)) != set(['fmt ', 'data'])
else:
return False
def __fmt_chunk__(self):
for (sub_header, nondecoder, data) in self.sub_frames():
if ((sub_header == 1) and nondecoder):
for (chunk_id, chunk_data) in __riff_chunks__(data):
if (chunk_id == 'fmt '):
return chunk_data
else:
return None
def frames(self):
f = file(self.filename)
remaining_samples = None
try:
while ((remaining_samples is None) or (remaining_samples > 0)):
try:
header = WavPackAudio.HEADER.parse(
f.read(WavPackAudio.HEADER.sizeof()))
except construct.ConstError:
raise InvalidFile(_(u'WavPack header ID invalid'))
if (remaining_samples is None):
remaining_samples = (header.total_samples - \
header.block_samples)
else:
remaining_samples -= header.block_samples
data = f.read(header.block_size - 24)
yield (header, data)
finally:
f.close()
def sub_frames(self):
import cStringIO
for (header, data) in self.frames():
total_size = len(data)
data = cStringIO.StringIO(data)
while (data.tell() < total_size):
sub_header = WavPackAudio.SUB_HEADER.parse_stream(data)
if (sub_header.actual_size_1_less):
yield (sub_header.metadata_function,
sub_header.nondecoder_data,
data.read((sub_header.size * 2) - 1))
data.read(1)
else:
yield (sub_header.metadata_function,
sub_header.nondecoder_data,
data.read(sub_header.size * 2))
def __read_info__(self):
f = file(self.filename)
try:
try:
header = WavPackAudio.HEADER.parse(
f.read(WavPackAudio.HEADER.sizeof()))
except construct.ConstError:
raise InvalidFile(_(u'WavPack header ID invalid'))
self.__samplerate__ = WavPackAudio.SAMPLING_RATE[(
header.sampling_rate_high << 1) | header.sampling_rate_low]
self.__bitspersample__ = WavPackAudio.BITS_PER_SAMPLE[
header.bits_per_sample]
self.__total_frames__ = header.total_samples
self.__channels__ = 0
#go through as many headers as necessary
#to count the number of channels
if (header.mono_output):
self.__channels__ += 1
else:
self.__channels__ += 2
while (not header.final_block_in_sequence):
f.seek(header.block_size - 24, 1)
header = WavPackAudio.HEADER.parse(
f.read(WavPackAudio.HEADER.sizeof()))
if (header.mono_output):
self.__channels__ += 1
else:
self.__channels__ += 2
finally:
f.close()
def bits_per_sample(self):
return self.__bitspersample__
def channels(self):
return self.__channels__
def total_frames(self):
return self.__total_frames__
def sample_rate(self):
return self.__samplerate__
@classmethod
def from_pcm(cls, filename, pcmreader, compression=None):
compression_param = {
"fast": ["-f"],
"standard": [],
"high": ["-h"],
"veryhigh": ["-hh"]
}
if (str(compression) not in cls.COMPRESSION_MODES):
compression = cls.DEFAULT_COMPRESSION
if ('--raw-pcm' in cls.__wavpack_help__()):
if (filename.endswith(".wv")):
devnull = file(os.devnull, 'ab')
if (pcmreader.channels > 18):
raise UnsupportedChannelMask()
elif (pcmreader.channels > 2):
order_map = {
"front_left": "FL",
"front_right": "FR",
"front_center": "FC",
"low_frequency": "LFE",
"back_left": "BL",
"back_right": "BR",
"front_left_of_center": "FLC",
"front_right_of_center": "FRC",
"back_center": "BC",
"side_left": "SL",
"side_right": "SR",
"top_center": "TC",
"top_front_left": "TFL",
"top_front_center": "TFC",
"top_front_right": "TFR",
"top_back_left": "TBL",
"top_back_center": "TBC",
"top_back_right": "TBR"
}
channel_order = [
"--channel-order=%s" % (",".join([
order_map[channel] for channel in ChannelMask(
pcmreader.channel_mask).channels()
]))
]
else:
channel_order = []
sub = subprocess.Popen([BIN['wavpack']] + \
compression_param[compression] + \
['-q','-y',
"--raw-pcm=%(sr)s,%(bps)s,%(ch)s"%\
{"sr":pcmreader.sample_rate,
"bps":pcmreader.bits_per_sample,
"ch":pcmreader.channels}] + \
channel_order + \
['-','-o',filename],
stdout=devnull,
stderr=devnull,
stdin=subprocess.PIPE,
preexec_fn=ignore_sigint)
transfer_framelist_data(pcmreader, sub.stdin.write)
devnull.close()
sub.stdin.close()
if (sub.wait() == 0):
return WavPackAudio(filename)
else:
raise EncodingError(BIN['wavpack'])
else:
import tempfile
tempdir = tempfile.mkdtemp()
symlink = os.path.join(tempdir,
os.path.basename(filename) + ".wv")
try:
os.symlink(os.path.abspath(filename), symlink)
cls.from_pcm(symlink, pcmreader, compression)
return WavPackAudio(filename)
finally:
os.unlink(symlink)
os.rmdir(tempdir)
else:
import tempfile
f = tempfile.NamedTemporaryFile(suffix=".wav")
w = WaveAudio.from_pcm(f.name, pcmreader)
try:
return cls.from_wave(filename, w.filename, compression)
finally:
del (w)
f.close()
def to_wave(self, wave_filename):
devnull = file(os.devnull, 'ab')
#WavPack stupidly refuses to run if the filename doesn't end with .wv
if (self.filename.endswith(".wv")):
sub = subprocess.Popen([
BIN['wvunpack'], '-q', '-y', self.filename, '-o', wave_filename
],
stdout=devnull,
stderr=devnull)
if (sub.wait() != 0):
raise EncodingError()
else:
#create a temporary symlink to the current file
#rather than rewrite the whole thing
import tempfile
tempdir = tempfile.mkdtemp()
symlink = os.path.join(tempdir,
os.path.basename(self.filename) + ".wv")
try:
os.symlink(os.path.abspath(self.filename), symlink)
WavPackAudio(symlink).to_wave(wave_filename)
finally:
os.unlink(symlink)
os.rmdir(tempdir)
def to_pcm(self):
if (self.filename.endswith(".wv")):
if ('-r' in WavPackAudio.__wvunpack_help__()):
sub = subprocess.Popen([
BIN['wvunpack'], '-q', '-y', self.filename, '-r', '-o', '-'
],
stdout=subprocess.PIPE,
stderr=file(os.devnull, 'ab'))
return PCMReader(sub.stdout,
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(self.channel_mask()),
bits_per_sample=self.bits_per_sample(),
process=sub)
else:
sub = subprocess.Popen(
[BIN['wvunpack'], '-q', '-y', self.filename, '-o', '-'],
stdout=subprocess.PIPE,
stderr=file(os.devnull, 'ab'))
return WaveReader(sub.stdout,
sample_rate=self.sample_rate(),
channels=self.channels(),
channel_mask=int(self.channel_mask()),
bits_per_sample=self.bits_per_sample(),
process=sub)
else:
#create a temporary symlink to the current file
#rather than rewrite the whole thing
(tempdir, symlink) = SymlinkPCMReader.new(self.filename, ".wv")
return SymlinkPCMReader(
WavPackAudio(symlink).to_pcm(), tempdir, symlink)
@classmethod
def from_wave(cls, filename, wave_filename, compression=None):
if (str(compression) not in cls.COMPRESSION_MODES):
compression = cls.DEFAULT_COMPRESSION
compression_param = {
"fast": ["-f"],
"standard": [],
"high": ["-h"],
"veryhigh": ["-hh"]
}
#wavpack will add a .wv suffix if there isn't one
#this isn't desired behavior
if (filename.endswith(".wv")):
devnull = file(os.devnull, 'ab')
sub = subprocess.Popen([BIN['wavpack'],
wave_filename] + \
compression_param[compression] + \
['-q','-y','-o',
filename],
stdout=devnull,
stderr=devnull,
preexec_fn=ignore_sigint)
devnull.close()
if (sub.wait() == 0):
return WavPackAudio(filename)
else:
raise EncodingError(BIN['wavpack'])
else:
import tempfile
tempdir = tempfile.mkdtemp()
symlink = os.path.join(tempdir, os.path.basename(filename) + ".wv")
try:
os.symlink(os.path.abspath(filename), symlink)
cls.from_wave(symlink, wave_filename, compression)
return WavPackAudio(filename)
finally:
os.unlink(symlink)
os.rmdir(tempdir)
@classmethod
def __wavpack_help__(cls):
devnull = open(os.devnull, "wb")
sub = subprocess.Popen([BIN["wavpack"], "--help"],
stdout=subprocess.PIPE,
stderr=devnull)
help_data = sub.stdout.read()
sub.stdout.close()
devnull.close()
sub.wait()
return help_data
@classmethod
def __wvunpack_help__(cls):
devnull = open(os.devnull, "wb")
sub = subprocess.Popen([BIN["wvunpack"], "--help"],
stdout=subprocess.PIPE,
stderr=devnull)
help_data = sub.stdout.read()
sub.stdout.close()
devnull.close()
sub.wait()
return help_data
@classmethod
def add_replay_gain(cls, filenames):
track_names = [
track.filename for track in open_files(filenames)
if isinstance(track, cls)
]
if ((len(track_names) > 0) and BIN.can_execute(BIN['wvgain'])):
devnull = file(os.devnull, 'ab')
sub = subprocess.Popen([BIN['wvgain'], '-q', '-a'] + track_names,
stdout=devnull,
stderr=devnull)
sub.wait()
devnull.close()
@classmethod
def can_add_replay_gain(cls):
return BIN.can_execute(BIN['wvgain'])
@classmethod
def lossless_replay_gain(cls):
return True
def replay_gain(self):
metadata = self.get_metadata()
if (metadata is None):
return None
if (set([
'replaygain_track_gain', 'replaygain_track_peak',
'replaygain_album_gain', 'replaygain_album_peak'
]).issubset(metadata.keys())): #we have ReplayGain data
try:
return ReplayGain(
unicode(metadata['replaygain_track_gain'])[0:-len(" dB")],
unicode(metadata['replaygain_track_peak']),
unicode(metadata['replaygain_album_gain'])[0:-len(" dB")],
unicode(metadata['replaygain_album_peak']))
except ValueError:
return None
else:
return None
def get_cuesheet(self):
import cue
metadata = self.get_metadata()
if ((metadata is not None) and ('Cuesheet' in metadata.keys())):
try:
return cue.parse(
cue.tokens(
unicode(metadata['Cuesheet']).encode(
'utf-8', 'replace')))
except cue.CueException:
#unlike FLAC, just because a cuesheet is embedded
#does not mean it is compliant
return None
else:
return None
def set_cuesheet(self, cuesheet):
import os.path
import cue
if (cuesheet is None):
return
metadata = self.get_metadata()
if (metadata is None):
metadata = WavePackAPEv2.converted(MetaData())
metadata['Cuesheet'] = WavePackAPEv2.ITEM.string(
'Cuesheet',
cue.Cuesheet.file(cuesheet,
os.path.basename(self.filename)).decode(
'ascii', 'replace'))
self.set_metadata(metadata)
class __JPEG__(ImageMetrics):
SEGMENT_HEADER = construct.Struct('segment_header',
construct.Const(construct.Byte('header'),0xFF),
construct.Byte('type'),
construct.If(
lambda ctx: ctx['type'] not in (0xD8,0xD9),
construct.UBInt16('length')))
APP0 = construct.Struct('JFIF_segment_marker',
construct.String('identifier',5),
construct.Byte('major_version'),
construct.Byte('minor_version'),
construct.Byte('density_units'),
construct.UBInt16('x_density'),
construct.UBInt16('y_density'),
construct.Byte('thumbnail_width'),
construct.Byte('thumbnail_height'))
SOF = construct.Struct('start_of_frame',
construct.Byte('data_precision'),
construct.UBInt16('image_height'),
construct.UBInt16('image_width'),
construct.Byte('components'))
def __init__(self, width, height, bits_per_pixel):
ImageMetrics.__init__(self, width, height, bits_per_pixel,
0, u'image/jpeg')
@classmethod
def parse(cls, file):
try:
header = cls.SEGMENT_HEADER.parse_stream(file)
if (header.type != 0xD8):
raise InvalidJPEG(_(u'Invalid JPEG header'))
segment = cls.SEGMENT_HEADER.parse_stream(file)
while (segment.type != 0xD9):
if (segment.type == 0xDA):
break
if (segment.type in (0xC0,0xC1,0xC2,0xC3,
0xC5,0XC5,0xC6,0xC7,
0xC9,0xCA,0xCB,0xCD,
0xCE,0xCF)): #start of frame
segment_data = cStringIO.StringIO(
file.read(segment.length - 2))
frame0 = cls.SOF.parse_stream(segment_data)
segment_data.close()
return __JPEG__(width = frame0.image_width,
height = frame0.image_height,
bits_per_pixel = (frame0.data_precision * \
frame0.components))
else:
file.seek(segment.length - 2,1)
segment = cls.SEGMENT_HEADER.parse_stream(file)
raise InvalidJPEG(_(u'Start of frame not found'))
except construct.ConstError:
raise InvalidJPEG(_(u"Invalid JPEG segment marker at 0x%X") % \
(file.tell()))
class __TIFF__(ImageMetrics):
HEADER = construct.Struct('header',
construct.String('byte_order',2),
construct.Switch('order',
lambda ctx: ctx['byte_order'],
{"II":construct.Embed(
construct.Struct('little_endian',
construct.Const(construct.ULInt16('version'),42),
construct.ULInt32('offset'))),
"MM":construct.Embed(
construct.Struct('big_endian',
construct.Const(construct.UBInt16('version'),42),
construct.UBInt32('offset')))}))
L_IFD = construct.Struct('ifd',
construct.PrefixedArray(
length_field=construct.ULInt16('length'),
subcon=construct.Struct('tags',
construct.ULInt16('id'),
construct.ULInt16('type'),
construct.ULInt32('count'),
construct.ULInt32('offset'))),
construct.ULInt32('next'))
B_IFD = construct.Struct('ifd',
construct.PrefixedArray(
length_field=construct.UBInt16('length'),
subcon=construct.Struct('tags',
construct.UBInt16('id'),
construct.UBInt16('type'),
construct.UBInt32('count'),
construct.UBInt32('offset'))),
construct.UBInt32('next'))
def __init__(self, width, height, bits_per_pixel, color_count):
ImageMetrics.__init__(self, width, height,
bits_per_pixel, color_count,
u'image/tiff')
@classmethod
def b_tag_value(cls, file, tag):
subtype = {1:construct.Byte("data"),
2:construct.CString("data"),
3:construct.UBInt16("data"),
4:construct.UBInt32("data"),
5:construct.Struct("data",
construct.UBInt32("high"),
construct.UBInt32("low"))}[tag.type]
data = construct.StrictRepeater(tag.count,
subtype)
if ((tag.type != 2) and (data.sizeof() <= 4)):
return tag.offset
else:
file.seek(tag.offset,0)
return data.parse_stream(file)
@classmethod
def l_tag_value(cls, file, tag):
subtype = {1:construct.Byte("data"),
2:construct.CString("data"),
3:construct.ULInt16("data"),
4:construct.ULInt32("data"),
5:construct.Struct("data",
construct.ULInt32("high"),
construct.ULInt32("low"))}[tag.type]
data = construct.StrictRepeater(tag.count,
subtype)
if ((tag.type != 2) and (data.sizeof() <= 4)):
return tag.offset
else:
file.seek(tag.offset,0)
return data.parse_stream(file)
@classmethod
def parse(cls, file):
width = 0
height = 0
bits_per_sample = 0
color_count = 0
try:
header = cls.HEADER.parse_stream(file)
if (header.byte_order == 'II'):
IFD = cls.L_IFD
tag_value = cls.l_tag_value
elif (header.byte_order == 'MM'):
IFD = cls.B_IFD
tag_value = cls.b_tag_value
else:
raise InvalidTIFF(_(u'Invalid byte order'))
file.seek(header.offset,0)
ifd = IFD.parse_stream(file)
while (True):
for tag in ifd.tags:
if (tag.id == 0x0100):
width = tag_value(file,tag)
elif (tag.id == 0x0101):
height = tag_value(file,tag)
elif (tag.id == 0x0102):
try:
bits_per_sample = sum(tag_value(file,tag))
except TypeError:
bits_per_sample = tag_value(file,tag)
elif (tag.id == 0x0140):
color_count = tag.count / 3
else:
pass
if (ifd.next == 0x00):
break
else:
file.seek(ifd.next,0)
ifd = IFD.parse_stream(file)
return __TIFF__(width,height,bits_per_sample,color_count)
except construct.ConstError:
raise InvalidTIFF(_(u'Invalid TIFF'))
class __PNG__(ImageMetrics):
HEADER = construct.Const(construct.String('header',8),
'89504e470d0a1a0a'.decode('hex'))
CHUNK_HEADER = construct.Struct('chunk',
construct.UBInt32('length'),
construct.String('type',4))
CHUNK_FOOTER = construct.Struct('crc32',
construct.UBInt32('crc'))
IHDR = construct.Struct('IHDR',
construct.UBInt32('width'),
construct.UBInt32('height'),
construct.Byte('bit_depth'),
construct.Byte('color_type'),
construct.Byte('compression_method'),
construct.Byte('filter_method'),
construct.Byte('interlace_method'))
def __init__(self, width, height, bits_per_pixel, color_count):
ImageMetrics.__init__(self, width, height, bits_per_pixel, color_count,
u'image/png')
@classmethod
def parse(cls, file):
ihdr = None
plte = None
try:
header = cls.HEADER.parse_stream(file)
chunk_header = cls.CHUNK_HEADER.parse_stream(file)
data = file.read(chunk_header.length)
chunk_footer = cls.CHUNK_FOOTER.parse_stream(file)
while (chunk_header.type != 'IEND'):
if (chunk_header.type == 'IHDR'):
ihdr = cls.IHDR.parse(data)
elif (chunk_header.type == 'PLTE'):
plte = data
chunk_header = cls.CHUNK_HEADER.parse_stream(file)
data = file.read(chunk_header.length)
chunk_footer = cls.CHUNK_FOOTER.parse_stream(file)
if (ihdr.color_type == 0): #grayscale
bits_per_pixel = ihdr.bit_depth
color_count = 0
elif (ihdr.color_type == 2): #RGB
bits_per_pixel = ihdr.bit_depth * 3
color_count = 0
elif (ihdr.color_type == 3): #palette
bits_per_pixel = 8
if ((len(plte) % 3) != 0):
raise InvalidPNG(_(u'Invalid PLTE chunk length'))
else:
color_count = len(plte) / 3
elif (ihdr.color_type == 4): #grayscale + alpha
bits_per_pixel = ihdr.bit_depth * 2
color_count = 0
elif (ihdr.color_type == 6): #RGB + alpha
bits_per_pixel = ihdr.bit_depth * 4
color_count = 0
return __PNG__(ihdr.width,ihdr.height,bits_per_pixel,color_count)
except construct.ConstError:
raise InvalidPNG(_(u'Invalid PNG'))