Libav
flacenc.c
Go to the documentation of this file.
1 /*
2  * raw FLAC muxer
3  * Copyright (c) 2006-2009 Justin Ruggles
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
23 #include "libavutil/opt.h"
24 #include "libavcodec/flac.h"
25 #include "avformat.h"
26 #include "flacenc.h"
27 #include "vorbiscomment.h"
28 #include "libavcodec/bytestream.h"
29 
30 
31 typedef struct FlacMuxerContext {
32  const AVClass *class;
34 
35  /* updated streaminfo sent by the encoder at the end */
38 
39 static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
40  int last_block)
41 {
42  avio_w8(pb, last_block ? 0x81 : 0x01);
43  avio_wb24(pb, n_padding_bytes);
44  while (n_padding_bytes > 0) {
45  avio_w8(pb, 0);
46  n_padding_bytes--;
47  }
48  return 0;
49 }
50 
52  int last_block, int bitexact)
53 {
54  const char *vendor = bitexact ? "Libav" : LIBAVFORMAT_IDENT;
55  unsigned int len;
56  uint8_t *p, *p0;
57 
59 
60  len = ff_vorbiscomment_length(*m, vendor);
61  p0 = av_malloc(len+4);
62  if (!p0)
63  return AVERROR(ENOMEM);
64  p = p0;
65 
66  bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
67  bytestream_put_be24(&p, len);
68  ff_vorbiscomment_write(&p, m, vendor);
69 
70  avio_write(pb, p0, len+4);
71  av_freep(&p0);
72  p = NULL;
73 
74  return 0;
75 }
76 
77 static int flac_write_header(struct AVFormatContext *s)
78 {
79  int ret;
80  AVCodecContext *codec = s->streams[0]->codec;
82 
83  if (!c->write_header)
84  return 0;
85 
86  ret = ff_flac_write_header(s->pb, codec->extradata,
87  codec->extradata_size, 0);
88  if (ret)
89  return ret;
90 
91  /* add the channel layout tag */
92  if (codec->channel_layout &&
93  !(codec->channel_layout & ~0x3ffffULL) &&
95  AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
96  NULL, 0);
97 
98  if (chmask) {
99  av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
100  "already present, this muxer will not overwrite it.\n");
101  } else {
102  uint8_t buf[32];
103  snprintf(buf, sizeof(buf), "0x%"PRIx64, codec->channel_layout);
104  av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
105  }
106  }
107 
108  ret = flac_write_block_comment(s->pb, &s->metadata, 0,
110  if (ret)
111  return ret;
112 
113  /* The command line flac encoder defaults to placing a seekpoint
114  * every 10s. So one might add padding to allow that later
115  * but there seems to be no simple way to get the duration here.
116  * So let's try the flac default of 8192 bytes */
117  flac_write_block_padding(s->pb, 8192, 1);
118 
119  return ret;
120 }
121 
122 static int flac_write_trailer(struct AVFormatContext *s)
123 {
124  AVIOContext *pb = s->pb;
125  int64_t file_size;
126  FlacMuxerContext *c = s->priv_data;
127  uint8_t *streaminfo = c->streaminfo ? c->streaminfo :
128  s->streams[0]->codec->extradata;
129 
130  if (!c->write_header || !streaminfo)
131  return 0;
132 
133  if (pb->seekable) {
134  /* rewrite the STREAMINFO header block data */
135  file_size = avio_tell(pb);
136  avio_seek(pb, 8, SEEK_SET);
137  avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
138  avio_seek(pb, file_size, SEEK_SET);
139  avio_flush(pb);
140  } else {
141  av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
142  }
143 
144  av_freep(&c->streaminfo);
145 
146  return 0;
147 }
148 
149 static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
150 {
151  FlacMuxerContext *c = s->priv_data;
152  uint8_t *streaminfo;
153  int streaminfo_size;
154 
155  /* check for updated streaminfo */
157  &streaminfo_size);
158  if (streaminfo && streaminfo_size == FLAC_STREAMINFO_SIZE) {
159  av_freep(&c->streaminfo);
160 
162  if (!c->streaminfo)
163  return AVERROR(ENOMEM);
164  memcpy(c->streaminfo, streaminfo, FLAC_STREAMINFO_SIZE);
165  }
166 
167  if (pkt->size)
168  avio_write(s->pb, pkt->data, pkt->size);
169  return 0;
170 }
171 
172 static const AVOption flacenc_options[] = {
173  { "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
174  { NULL },
175 };
176 
177 static const AVClass flac_muxer_class = {
178  .class_name = "flac muxer",
179  .item_name = av_default_item_name,
180  .option = flacenc_options,
181  .version = LIBAVUTIL_VERSION_INT,
182 };
183 
185  .name = "flac",
186  .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
187  .priv_data_size = sizeof(FlacMuxerContext),
188  .mime_type = "audio/x-flac",
189  .extensions = "flac",
190  .audio_codec = AV_CODEC_ID_FLAC,
191  .video_codec = AV_CODEC_ID_NONE,
196  .priv_class = &flac_muxer_class,
197 };
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:62
Bytestream IO Context.
Definition: avio.h:68
AVOption.
Definition: opt.h:234
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:129
static int write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: assenc.c:58
static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes, int last_block)
Definition: flacenc.c:39
AVOutputFormat ff_flac_muxer
Definition: flacenc.c:184
int size
Definition: avcodec.h:974
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:186
int ff_flac_is_native_layout(uint64_t channel_layout)
int ff_vorbiscomment_write(uint8_t **p, AVDictionary **m, const char *vendor_string)
Write a VorbisComment into a buffer.
Definition: vorbiscomment.c:53
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:198
Format I/O context.
Definition: avformat.h:922
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:38
uint8_t
AVOptions.
uint8_t * streaminfo
Definition: flacenc.c:36
static int flac_write_header(struct AVFormatContext *s)
Definition: flacenc.c:77
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1164
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:990
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:38
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1033
uint8_t * data
Definition: avcodec.h:973
static int flags
Definition: log.c:44
int ff_vorbiscomment_length(AVDictionary *m, const char *vendor_string)
Calculate the length in bytes of a VorbisComment.
Definition: vorbiscomment.c:40
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:219
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:165
#define AVFMT_FLAG_BITEXACT
When muxing, try to avoid writing any random/volatile data to the output.
Definition: avformat.h:1050
static int flac_write_trailer(struct AVFormatContext *s)
Definition: flacenc.c:122
static int write_trailer(AVFormatContext *s)
Definition: assenc.c:64
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:264
const AVMetadataConv ff_vorbiscomment_metadata_conv[]
VorbisComment metadata conversion mapping.
Definition: vorbiscomment.c:33
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1130
FLAC (Free Lossless Audio Codec) decoder/demuxer common functions.
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:150
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:168
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1852
static const AVOption flacenc_options[]
Definition: flacenc.c:172
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:718
int write_header
Definition: flacenc.c:33
#define LIBAVFORMAT_IDENT
Definition: version.h:44
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:117
int void avio_flush(AVIOContext *s)
Definition: aviobuf.c:180
audio channel layout utility functions
void avio_wb24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:354
const char * name
Definition: avformat.h:446
#define FLAC_STREAMINFO_SIZE
Definition: flac.h:34
int ff_flac_write_header(AVIOContext *pb, uint8_t *extradata, int extradata_size, int last_block)
static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m, int last_block, int bitexact)
Definition: flacenc.c:51
LIBAVUTIL_VERSION_INT
Definition: eval.c:55
#define AVFMT_NOTIMESTAMPS
Format does not need / have any timestamps.
Definition: avformat.h:416
NULL
Definition: eval.c:55
static const AVClass flac_muxer_class
Definition: flacenc.c:177
AVIOContext * pb
I/O context.
Definition: avformat.h:964
av_default_item_name
Definition: dnxhdenc.c:52
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:144
main external API structure.
Definition: avcodec.h:1050
int extradata_size
Definition: avcodec.h:1165
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:68
Describe the class of an AVClass context structure.
Definition: log.h:33
static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
Definition: flacenc.c:149
Main libavformat public API header.
void ff_metadata_conv(AVDictionary **pm, const AVMetadataConv *d_conv, const AVMetadataConv *s_conv)
Definition: metadata.c:26
int len
void * priv_data
Format private data.
Definition: avformat.h:950
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:380
uint8_t * av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type, int *size)
Get side information from packet.
Definition: avpacket.c:287
This structure stores compressed data.
Definition: avcodec.h:950