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 {
37 static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
40 avio_w8(pb, last_block ? 0x81 : 0x01);
41 avio_wb24(pb, n_padding_bytes);
42 ffio_fill(pb, 0, n_padding_bytes);
46 static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
47 int last_block, int bitexact)
49 const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
53 ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
55 len = ff_vorbiscomment_length(*m, vendor);
56 p0 = av_malloc(len+4);
58 return AVERROR(ENOMEM);
61 bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
62 bytestream_put_be24(&p, len);
63 ff_vorbiscomment_write(&p, m, vendor);
65 avio_write(pb, p0, len+4);
72 static int flac_write_header(struct AVFormatContext *s)
75 int padding = s->metadata_header_padding;
76 AVCodecContext *codec = s->streams[0]->codec;
77 FlacMuxerContext *c = s->priv_data;
82 if (s->nb_streams > 1) {
83 av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
84 return AVERROR(EINVAL);
86 if (codec->codec_id != AV_CODEC_ID_FLAC) {
87 av_log(s, AV_LOG_ERROR, "unsupported codec\n");
88 return AVERROR(EINVAL);
93 /* The FLAC specification states that 24 bits are used to represent the
94 * size of a metadata block so we must clip this value to 2^24-1. */
95 padding = av_clip_c(padding, 0, 16777215);
97 ret = ff_flac_write_header(s->pb, codec, 0);
101 /* add the channel layout tag */
102 if (codec->channel_layout &&
103 !(codec->channel_layout & ~0x3ffffULL) &&
104 !ff_flac_is_native_layout(codec->channel_layout)) {
105 AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
109 av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
110 "already present, this muxer will not overwrite it.\n");
113 snprintf(buf, sizeof(buf), "0x%"PRIx64, codec->channel_layout);
114 av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
118 ret = flac_write_block_comment(s->pb, &s->metadata, !padding,
119 s->flags & AVFMT_FLAG_BITEXACT);
123 /* The command line flac encoder defaults to placing a seekpoint
124 * every 10s. So one might add padding to allow that later
125 * but there seems to be no simple way to get the duration here.
126 * So just add the amount requested by the user. */
128 flac_write_block_padding(s->pb, padding, 1);
133 static int flac_write_trailer(struct AVFormatContext *s)
135 AVIOContext *pb = s->pb;
137 enum FLACExtradataFormat format;
139 FlacMuxerContext *c = s->priv_data;
141 if (!c->write_header)
144 if (!avpriv_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
148 /* rewrite the STREAMINFO header block data */
149 file_size = avio_tell(pb);
150 avio_seek(pb, 8, SEEK_SET);
151 avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
152 avio_seek(pb, file_size, SEEK_SET);
155 av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
160 static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
162 avio_write(s->pb, pkt->data, pkt->size);
166 static const AVOption flacenc_options[] = {
167 { "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
171 static const AVClass flac_muxer_class = {
172 .class_name = "flac muxer",
173 .item_name = av_default_item_name,
174 .option = flacenc_options,
175 .version = LIBAVUTIL_VERSION_INT,
178 AVOutputFormat ff_flac_muxer = {
180 .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
181 .priv_data_size = sizeof(FlacMuxerContext),
182 .mime_type = "audio/x-flac",
183 .extensions = "flac",
184 .audio_codec = AV_CODEC_ID_FLAC,
185 .video_codec = AV_CODEC_ID_NONE,
186 .write_header = flac_write_header,
187 .write_packet = flac_write_packet,
188 .write_trailer = flac_write_trailer,
189 .flags = AVFMT_NOTIMESTAMPS,
190 .priv_class = &flac_muxer_class,