3 * Copyright (c) 2006-2009 Justin Ruggles
5 * This file is part of FFmpeg.
7 * FFmpeg 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.
12 * FFmpeg 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/channel_layout.h"
23 #include "libavutil/opt.h"
24 #include "libavcodec/flac.h"
26 #include "avio_internal.h"
28 #include "vorbiscomment.h"
29 #include "libavcodec/bytestream.h"
32 typedef struct FlacMuxerContext
{
36 /* updated streaminfo sent by the encoder at the end */
40 static int flac_write_block_padding(AVIOContext
*pb
, unsigned int n_padding_bytes
,
43 avio_w8(pb
, last_block
? 0x81 : 0x01);
44 avio_wb24(pb
, n_padding_bytes
);
45 ffio_fill(pb
, 0, n_padding_bytes
);
49 static int flac_write_block_comment(AVIOContext
*pb
, AVDictionary
**m
,
50 int last_block
, int bitexact
)
52 const char *vendor
= bitexact
? "ffmpeg" : LIBAVFORMAT_IDENT
;
56 ff_metadata_conv(m
, ff_vorbiscomment_metadata_conv
, NULL
);
58 len
= ff_vorbiscomment_length(*m
, vendor
);
59 p0
= av_malloc(len
+4);
61 return AVERROR(ENOMEM
);
64 bytestream_put_byte(&p
, last_block
? 0x84 : 0x04);
65 bytestream_put_be24(&p
, len
);
66 ff_vorbiscomment_write(&p
, m
, vendor
);
68 avio_write(pb
, p0
, len
+4);
75 static int flac_write_header(struct AVFormatContext
*s
)
78 int padding
= s
->metadata_header_padding
;
79 AVCodecContext
*codec
= s
->streams
[0]->codec
;
80 FlacMuxerContext
*c
= s
->priv_data
;
85 if (s
->nb_streams
> 1) {
86 av_log(s
, AV_LOG_ERROR
, "only one stream is supported\n");
87 return AVERROR(EINVAL
);
89 if (codec
->codec_id
!= AV_CODEC_ID_FLAC
) {
90 av_log(s
, AV_LOG_ERROR
, "unsupported codec\n");
91 return AVERROR(EINVAL
);
96 /* The FLAC specification states that 24 bits are used to represent the
97 * size of a metadata block so we must clip this value to 2^24-1. */
98 padding
= av_clip(padding
, 0, 16777215);
100 ret
= ff_flac_write_header(s
->pb
, codec
->extradata
,
101 codec
->extradata_size
, 0);
105 /* add the channel layout tag */
106 if (codec
->channel_layout
&&
107 !(codec
->channel_layout
& ~0x3ffffULL
) &&
108 !ff_flac_is_native_layout(codec
->channel_layout
)) {
109 AVDictionaryEntry
*chmask
= av_dict_get(s
->metadata
, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
113 av_log(s
, AV_LOG_WARNING
, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
114 "already present, this muxer will not overwrite it.\n");
117 snprintf(buf
, sizeof(buf
), "0x%"PRIx64
, codec
->channel_layout
);
118 av_dict_set(&s
->metadata
, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf
, 0);
122 ret
= flac_write_block_comment(s
->pb
, &s
->metadata
, !padding
,
123 s
->flags
& AVFMT_FLAG_BITEXACT
);
127 /* The command line flac encoder defaults to placing a seekpoint
128 * every 10s. So one might add padding to allow that later
129 * but there seems to be no simple way to get the duration here.
130 * So just add the amount requested by the user. */
132 flac_write_block_padding(s
->pb
, padding
, 1);
137 static int flac_write_trailer(struct AVFormatContext
*s
)
139 AVIOContext
*pb
= s
->pb
;
141 FlacMuxerContext
*c
= s
->priv_data
;
142 uint8_t *streaminfo
= c
->streaminfo
? c
->streaminfo
:
143 s
->streams
[0]->codec
->extradata
;
145 if (!c
->write_header
|| !streaminfo
)
149 /* rewrite the STREAMINFO header block data */
150 file_size
= avio_tell(pb
);
151 avio_seek(pb
, 8, SEEK_SET
);
152 avio_write(pb
, streaminfo
, FLAC_STREAMINFO_SIZE
);
153 avio_seek(pb
, file_size
, SEEK_SET
);
156 av_log(s
, AV_LOG_WARNING
, "unable to rewrite FLAC header.\n");
159 av_freep(&c
->streaminfo
);
164 static int flac_write_packet(struct AVFormatContext
*s
, AVPacket
*pkt
)
166 FlacMuxerContext
*c
= s
->priv_data
;
170 /* check for updated streaminfo */
171 streaminfo
= av_packet_get_side_data(pkt
, AV_PKT_DATA_NEW_EXTRADATA
,
173 if (streaminfo
&& streaminfo_size
== FLAC_STREAMINFO_SIZE
) {
174 av_freep(&c
->streaminfo
);
176 c
->streaminfo
= av_malloc(FLAC_STREAMINFO_SIZE
);
178 return AVERROR(ENOMEM
);
179 memcpy(c
->streaminfo
, streaminfo
, FLAC_STREAMINFO_SIZE
);
183 avio_write(s
->pb
, pkt
->data
, pkt
->size
);
187 static const AVOption flacenc_options
[] = {
188 { "write_header", "Write the file header", offsetof(FlacMuxerContext
, write_header
), AV_OPT_TYPE_INT
, {.i64
= 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM
},
192 static const AVClass flac_muxer_class
= {
193 .class_name
= "flac muxer",
194 .item_name
= av_default_item_name
,
195 .option
= flacenc_options
,
196 .version
= LIBAVUTIL_VERSION_INT
,
199 AVOutputFormat ff_flac_muxer
= {
201 .long_name
= NULL_IF_CONFIG_SMALL("raw FLAC"),
202 .priv_data_size
= sizeof(FlacMuxerContext
),
203 .mime_type
= "audio/x-flac",
204 .extensions
= "flac",
205 .audio_codec
= AV_CODEC_ID_FLAC
,
206 .video_codec
= AV_CODEC_ID_NONE
,
207 .write_header
= flac_write_header
,
208 .write_packet
= flac_write_packet
,
209 .write_trailer
= flac_write_trailer
,
210 .flags
= AVFMT_NOTIMESTAMPS
,
211 .priv_class
= &flac_muxer_class
,