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
|
/*
* raw FLAC muxer
* Copyright (c) 2006-2009 Justin Ruggles
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libavcodec/flac.h"
#include "avformat.h"
#include "avio_internal.h"
#include "flacenc.h"
#include "vorbiscomment.h"
#include "libavcodec/bytestream.h"
typedef struct FlacMuxerContext {
const AVClass *class;
int write_header;
/* updated streaminfo sent by the encoder at the end */
uint8_t *streaminfo;
} FlacMuxerContext;
static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
int last_block)
{
avio_w8(pb, last_block ? 0x81 : 0x01);
avio_wb24(pb, n_padding_bytes);
ffio_fill(pb, 0, n_padding_bytes);
return 0;
}
static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
int last_block, int bitexact)
{
const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
unsigned int len;
uint8_t *p, *p0;
ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
len = ff_vorbiscomment_length(*m, vendor);
p0 = av_malloc(len+4);
if (!p0)
return AVERROR(ENOMEM);
p = p0;
bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
bytestream_put_be24(&p, len);
ff_vorbiscomment_write(&p, m, vendor);
avio_write(pb, p0, len+4);
av_freep(&p0);
p = NULL;
return 0;
}
static int flac_write_header(struct AVFormatContext *s)
{
int ret;
int padding = s->metadata_header_padding;
AVCodecContext *codec = s->streams[0]->codec;
FlacMuxerContext *c = s->priv_data;
if (!c->write_header)
return 0;
if (s->nb_streams > 1) {
av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
return AVERROR(EINVAL);
}
if (codec->codec_id != AV_CODEC_ID_FLAC) {
av_log(s, AV_LOG_ERROR, "unsupported codec\n");
return AVERROR(EINVAL);
}
if (padding < 0)
padding = 8192;
/* The FLAC specification states that 24 bits are used to represent the
* size of a metadata block so we must clip this value to 2^24-1. */
padding = av_clip_c(padding, 0, 16777215);
ret = ff_flac_write_header(s->pb, codec->extradata,
codec->extradata_size, 0);
if (ret)
return ret;
/* add the channel layout tag */
if (codec->channel_layout &&
!(codec->channel_layout & ~0x3ffffULL) &&
!ff_flac_is_native_layout(codec->channel_layout)) {
AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
NULL, 0);
if (chmask) {
av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
"already present, this muxer will not overwrite it.\n");
} else {
uint8_t buf[32];
snprintf(buf, sizeof(buf), "0x%"PRIx64, codec->channel_layout);
av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
}
}
ret = flac_write_block_comment(s->pb, &s->metadata, !padding,
s->flags & AVFMT_FLAG_BITEXACT);
if (ret)
return ret;
/* The command line flac encoder defaults to placing a seekpoint
* every 10s. So one might add padding to allow that later
* but there seems to be no simple way to get the duration here.
* So just add the amount requested by the user. */
if (padding)
flac_write_block_padding(s->pb, padding, 1);
return ret;
}
static int flac_write_trailer(struct AVFormatContext *s)
{
AVIOContext *pb = s->pb;
int64_t file_size;
FlacMuxerContext *c = s->priv_data;
uint8_t *streaminfo = c->streaminfo ? c->streaminfo :
s->streams[0]->codec->extradata;
if (!c->write_header || !streaminfo)
return 0;
if (pb->seekable) {
/* rewrite the STREAMINFO header block data */
file_size = avio_tell(pb);
avio_seek(pb, 8, SEEK_SET);
avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
avio_seek(pb, file_size, SEEK_SET);
avio_flush(pb);
} else {
av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
}
av_freep(&c->streaminfo);
return 0;
}
static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
FlacMuxerContext *c = s->priv_data;
uint8_t *streaminfo;
int streaminfo_size;
/* check for updated streaminfo */
streaminfo = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
&streaminfo_size);
if (streaminfo && streaminfo_size == FLAC_STREAMINFO_SIZE) {
av_freep(&c->streaminfo);
c->streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
if (!c->streaminfo)
return AVERROR(ENOMEM);
memcpy(c->streaminfo, streaminfo, FLAC_STREAMINFO_SIZE);
}
if (pkt->size)
avio_write(s->pb, pkt->data, pkt->size);
return 0;
}
static const AVOption flacenc_options[] = {
{ "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
{ NULL },
};
static const AVClass flac_muxer_class = {
.class_name = "flac muxer",
.item_name = av_default_item_name,
.option = flacenc_options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_flac_muxer = {
.name = "flac",
.long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
.priv_data_size = sizeof(FlacMuxerContext),
.mime_type = "audio/x-flac",
.extensions = "flac",
.audio_codec = AV_CODEC_ID_FLAC,
.video_codec = AV_CODEC_ID_NONE,
.write_header = flac_write_header,
.write_packet = flac_write_packet,
.write_trailer = flac_write_trailer,
.flags = AVFMT_NOTIMESTAMPS,
.priv_class = &flac_muxer_class,
};
|
