/
oggflac.py
161 lines (116 loc) · 4.65 KB
/
oggflac.py
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
# -*- coding: utf-8 -*-
# Copyright (C) 2006 Joe Wreschnig
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
"""Read and write Ogg FLAC comments.
This module handles FLAC files wrapped in an Ogg bitstream. The first
FLAC stream found is used. For 'naked' FLACs, see mutagen.flac.
This module is based off the specification at
http://flac.sourceforge.net/ogg_mapping.html.
"""
__all__ = ["OggFLAC", "Open", "delete"]
import struct
from ._compat import cBytesIO
from mutagen import StreamInfo
from mutagen.flac import StreamInfo as FLACStreamInfo, error as FLACError
from mutagen._vorbis import VCommentDict
from mutagen.ogg import OggPage, OggFileType, error as OggError
class error(OggError):
pass
class OggFLACHeaderError(error):
pass
class OggFLACStreamInfo(StreamInfo):
"""Ogg FLAC stream info."""
length = 0
"""File length in seconds, as a float"""
channels = 0
"""Number of channels"""
sample_rate = 0
"""Sample rate in Hz"""
def __init__(self, fileobj):
page = OggPage(fileobj)
while not page.packets[0].startswith(b"\x7FFLAC"):
page = OggPage(fileobj)
major, minor, self.packets, flac = struct.unpack(
">BBH4s", page.packets[0][5:13])
if flac != b"fLaC":
raise OggFLACHeaderError("invalid FLAC marker (%r)" % flac)
elif (major, minor) != (1, 0):
raise OggFLACHeaderError(
"unknown mapping version: %d.%d" % (major, minor))
self.serial = page.serial
# Skip over the block header.
stringobj = cBytesIO(page.packets[0][17:])
try:
flac_info = FLACStreamInfo(stringobj)
except FLACError as e:
raise OggFLACHeaderError(e)
for attr in ["min_blocksize", "max_blocksize", "sample_rate",
"channels", "bits_per_sample", "total_samples", "length"]:
setattr(self, attr, getattr(flac_info, attr))
def _post_tags(self, fileobj):
if self.length:
return
page = OggPage.find_last(fileobj, self.serial)
self.length = page.position / float(self.sample_rate)
def pprint(self):
return u"Ogg FLAC, %.2f seconds, %d Hz" % (
self.length, self.sample_rate)
class OggFLACVComment(VCommentDict):
def __init__(self, fileobj, info):
# data should be pointing at the start of an Ogg page, after
# the first FLAC page.
pages = []
complete = False
while not complete:
page = OggPage(fileobj)
if page.serial == info.serial:
pages.append(page)
complete = page.complete or (len(page.packets) > 1)
comment = cBytesIO(OggPage.to_packets(pages)[0][4:])
super(OggFLACVComment, self).__init__(comment, framing=False)
def _inject(self, fileobj, padding_func):
"""Write tag data into the FLAC Vorbis comment packet/page."""
# Ogg FLAC has no convenient data marker like Vorbis, but the
# second packet - and second page - must be the comment data.
fileobj.seek(0)
page = OggPage(fileobj)
while not page.packets[0].startswith(b"\x7FFLAC"):
page = OggPage(fileobj)
first_page = page
while not (page.sequence == 1 and page.serial == first_page.serial):
page = OggPage(fileobj)
old_pages = [page]
while not (old_pages[-1].complete or len(old_pages[-1].packets) > 1):
page = OggPage(fileobj)
if page.serial == first_page.serial:
old_pages.append(page)
packets = OggPage.to_packets(old_pages, strict=False)
# Set the new comment block.
data = self.write(framing=False)
data = packets[0][:1] + struct.pack(">I", len(data))[-3:] + data
packets[0] = data
new_pages = OggPage.from_packets(packets, old_pages[0].sequence)
OggPage.replace(fileobj, old_pages, new_pages)
class OggFLAC(OggFileType):
"""An Ogg FLAC file."""
_Info = OggFLACStreamInfo
_Tags = OggFLACVComment
_Error = OggFLACHeaderError
_mimes = ["audio/x-oggflac"]
info = None
"""A `OggFLACStreamInfo`"""
tags = None
"""A `VCommentDict`"""
def save(self, filename=None):
return super(OggFLAC, self).save(filename)
@staticmethod
def score(filename, fileobj, header):
return (header.startswith(b"OggS") * (
(b"FLAC" in header) + (b"fLaC" in header)))
Open = OggFLAC
def delete(filename):
"""Remove tags from a file."""
OggFLAC(filename).delete()