/usr/lib/pypy/dist-packages/mutagen/mp3/_util.py is in pypy-mutagen 1.36-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 | # -*- coding: utf-8 -*-
# Copyright 2015 Christoph Reiter
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
"""
http://www.codeproject.com/Articles/8295/MPEG-Audio-Frame-Header
http://wiki.hydrogenaud.io/index.php?title=MP3
"""
from functools import partial
from mutagen._util import cdata, BitReader
from mutagen._compat import xrange, iterbytes, cBytesIO
class LAMEError(Exception):
pass
class LAMEHeader(object):
"""http://gabriel.mp3-tech.org/mp3infotag.html"""
vbr_method = 0
"""0: unknown, 1: CBR, 2: ABR, 3/4/5: VBR, others: see the docs"""
lowpass_filter = 0
"""lowpass filter value in Hz. 0 means unknown"""
quality = -1
"""Encoding quality: 0..9"""
vbr_quality = -1
"""VBR quality: 0..9"""
track_peak = None
"""Peak signal amplitude as float. None if unknown."""
track_gain_origin = 0
"""see the docs"""
track_gain_adjustment = None
"""Track gain adjustment as float (for 89db replay gain) or None"""
album_gain_origin = 0
"""see the docs"""
album_gain_adjustment = None
"""Album gain adjustment as float (for 89db replay gain) or None"""
encoding_flags = 0
"""see docs"""
ath_type = -1
"""see docs"""
bitrate = -1
"""Bitrate in kbps. For VBR the minimum bitrate, for anything else
(CBR, ABR, ..) the target bitrate.
"""
encoder_delay_start = 0
"""Encoder delay in samples"""
encoder_padding_end = 0
"""Padding in samples added at the end"""
source_sample_frequency_enum = -1
"""see docs"""
unwise_setting_used = False
"""see docs"""
stereo_mode = 0
"""see docs"""
noise_shaping = 0
"""see docs"""
mp3_gain = 0
"""Applied MP3 gain -127..127. Factor is 2 ** (mp3_gain / 4)"""
surround_info = 0
"""see docs"""
preset_used = 0
"""lame preset"""
music_length = 0
"""Length in bytes excluding any ID3 tags"""
music_crc = -1
"""CRC16 of the data specified by music_length"""
header_crc = -1
"""CRC16 of this header and everything before (not checked)"""
def __init__(self, xing, fileobj):
"""Raises LAMEError if parsing fails"""
payload = fileobj.read(27)
if len(payload) != 27:
raise LAMEError("Not enough data")
# extended lame header
r = BitReader(cBytesIO(payload))
revision = r.bits(4)
if revision != 0:
raise LAMEError("unsupported header revision %d" % revision)
self.vbr_method = r.bits(4)
self.lowpass_filter = r.bits(8) * 100
# these have a different meaning for lame; expose them again here
self.quality = (100 - xing.vbr_scale) % 10
self.vbr_quality = (100 - xing.vbr_scale) // 10
track_peak_data = r.bytes(4)
if track_peak_data == b"\x00\x00\x00\x00":
self.track_peak = None
else:
# see PutLameVBR() in LAME's VbrTag.c
self.track_peak = (
cdata.uint32_be(track_peak_data) - 0.5) / 2 ** 23
track_gain_type = r.bits(3)
self.track_gain_origin = r.bits(3)
sign = r.bits(1)
gain_adj = r.bits(9) / 10.0
if sign:
gain_adj *= -1
if track_gain_type == 1:
self.track_gain_adjustment = gain_adj
else:
self.track_gain_adjustment = None
assert r.is_aligned()
album_gain_type = r.bits(3)
self.album_gain_origin = r.bits(3)
sign = r.bits(1)
album_gain_adj = r.bits(9) / 10.0
if album_gain_type == 2:
self.album_gain_adjustment = album_gain_adj
else:
self.album_gain_adjustment = None
self.encoding_flags = r.bits(4)
self.ath_type = r.bits(4)
self.bitrate = r.bits(8)
self.encoder_delay_start = r.bits(12)
self.encoder_padding_end = r.bits(12)
self.source_sample_frequency_enum = r.bits(2)
self.unwise_setting_used = r.bits(1)
self.stereo_mode = r.bits(3)
self.noise_shaping = r.bits(2)
sign = r.bits(1)
mp3_gain = r.bits(7)
if sign:
mp3_gain *= -1
self.mp3_gain = mp3_gain
r.skip(2)
self.surround_info = r.bits(3)
self.preset_used = r.bits(11)
self.music_length = r.bits(32)
self.music_crc = r.bits(16)
self.header_crc = r.bits(16)
assert r.is_aligned()
@classmethod
def parse_version(cls, fileobj):
"""Returns a version string and True if a LAMEHeader follows.
The passed file object will be positioned right before the
lame header if True.
Raises LAMEError if there is no lame version info.
"""
# http://wiki.hydrogenaud.io/index.php?title=LAME_version_string
data = fileobj.read(20)
if len(data) != 20:
raise LAMEError("Not a lame header")
if not data.startswith((b"LAME", b"L3.99")):
raise LAMEError("Not a lame header")
data = data.lstrip(b"EMAL")
major, data = data[0:1], data[1:].lstrip(b".")
minor = b""
for c in iterbytes(data):
if not c.isdigit():
break
minor += c
data = data[len(minor):]
try:
major = int(major.decode("ascii"))
minor = int(minor.decode("ascii"))
except ValueError:
raise LAMEError
# the extended header was added sometimes in the 3.90 cycle
# e.g. "LAME3.90 (alpha)" should still stop here.
# (I have seen such a file)
if (major, minor) < (3, 90) or (
(major, minor) == (3, 90) and data[-11:-10] == b"("):
flag = data.strip(b"\x00").rstrip().decode("ascii")
return u"%d.%d%s" % (major, minor, flag), False
if len(data) <= 11:
raise LAMEError("Invalid version: too long")
flag = data[:-11].rstrip(b"\x00")
flag_string = u""
patch = u""
if flag == b"a":
flag_string = u" (alpha)"
elif flag == b"b":
flag_string = u" (beta)"
elif flag == b"r":
patch = u".1+"
elif flag == b" ":
if (major, minor) > (3, 96):
patch = u".0"
else:
patch = u".0+"
elif flag == b"" or flag == b".":
patch = u".0+"
else:
flag_string = u" (?)"
# extended header, seek back to 9 bytes for the caller
fileobj.seek(-11, 1)
return u"%d.%d%s%s" % (major, minor, patch, flag_string), True
class XingHeaderError(Exception):
pass
class XingHeaderFlags(object):
FRAMES = 0x1
BYTES = 0x2
TOC = 0x4
VBR_SCALE = 0x8
class XingHeader(object):
frames = -1
"""Number of frames, -1 if unknown"""
bytes = -1
"""Number of bytes, -1 if unknown"""
toc = []
"""List of 100 file offsets in percent encoded as 0-255. E.g. entry
50 contains the file offset in percent at 50% play time.
Empty if unknown.
"""
vbr_scale = -1
"""VBR quality indicator 0-100. -1 if unknown"""
lame_header = None
"""A LAMEHeader instance or None"""
lame_version = u""
"""The version of the LAME encoder e.g. '3.99.0'. Empty if unknown"""
is_info = False
"""If the header started with 'Info' and not 'Xing'"""
def __init__(self, fileobj):
"""Parses the Xing header or raises XingHeaderError.
The file position after this returns is undefined.
"""
data = fileobj.read(8)
if len(data) != 8 or data[:4] not in (b"Xing", b"Info"):
raise XingHeaderError("Not a Xing header")
self.is_info = (data[:4] == b"Info")
flags = cdata.uint32_be_from(data, 4)[0]
if flags & XingHeaderFlags.FRAMES:
data = fileobj.read(4)
if len(data) != 4:
raise XingHeaderError("Xing header truncated")
self.frames = cdata.uint32_be(data)
if flags & XingHeaderFlags.BYTES:
data = fileobj.read(4)
if len(data) != 4:
raise XingHeaderError("Xing header truncated")
self.bytes = cdata.uint32_be(data)
if flags & XingHeaderFlags.TOC:
data = fileobj.read(100)
if len(data) != 100:
raise XingHeaderError("Xing header truncated")
self.toc = list(bytearray(data))
if flags & XingHeaderFlags.VBR_SCALE:
data = fileobj.read(4)
if len(data) != 4:
raise XingHeaderError("Xing header truncated")
self.vbr_scale = cdata.uint32_be(data)
try:
self.lame_version, has_header = LAMEHeader.parse_version(fileobj)
if has_header:
self.lame_header = LAMEHeader(self, fileobj)
except LAMEError:
pass
@classmethod
def get_offset(cls, info):
"""Calculate the offset to the Xing header from the start of the
MPEG header including sync based on the MPEG header's content.
"""
assert info.layer == 3
if info.version == 1:
if info.mode != 3:
return 36
else:
return 21
else:
if info.mode != 3:
return 21
else:
return 13
class VBRIHeaderError(Exception):
pass
class VBRIHeader(object):
version = 0
"""VBRI header version"""
quality = 0
"""Quality indicator"""
bytes = 0
"""Number of bytes"""
frames = 0
"""Number of frames"""
toc_scale_factor = 0
"""Scale factor of TOC entries"""
toc_frames = 0
"""Number of frames per table entry"""
toc = []
"""TOC"""
def __init__(self, fileobj):
"""Reads the VBRI header or raises VBRIHeaderError.
The file position is undefined after this returns
"""
data = fileobj.read(26)
if len(data) != 26 or not data.startswith(b"VBRI"):
raise VBRIHeaderError("Not a VBRI header")
offset = 4
self.version, offset = cdata.uint16_be_from(data, offset)
if self.version != 1:
raise VBRIHeaderError(
"Unsupported header version: %r" % self.version)
offset += 2 # float16.. can't do
self.quality, offset = cdata.uint16_be_from(data, offset)
self.bytes, offset = cdata.uint32_be_from(data, offset)
self.frames, offset = cdata.uint32_be_from(data, offset)
toc_num_entries, offset = cdata.uint16_be_from(data, offset)
self.toc_scale_factor, offset = cdata.uint16_be_from(data, offset)
toc_entry_size, offset = cdata.uint16_be_from(data, offset)
self.toc_frames, offset = cdata.uint16_be_from(data, offset)
toc_size = toc_entry_size * toc_num_entries
toc_data = fileobj.read(toc_size)
if len(toc_data) != toc_size:
raise VBRIHeaderError("VBRI header truncated")
self.toc = []
if toc_entry_size == 2:
unpack = partial(cdata.uint16_be_from, toc_data)
elif toc_entry_size == 4:
unpack = partial(cdata.uint32_be_from, toc_data)
else:
raise VBRIHeaderError("Invalid TOC entry size")
self.toc = [unpack(i)[0] for i in xrange(0, toc_size, toc_entry_size)]
@classmethod
def get_offset(cls, info):
"""Offset in bytes from the start of the MPEG header including sync"""
assert info.layer == 3
return 36
|