2 * codec2 muxer and demuxers
3 * Copyright (c) 2017 Tomas Härdin
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
23 #include "libavcodec/codec2utils.h"
24 #include "libavutil/intreadwrite.h"
25 #include "avio_internal.h"
32 #define CODEC2_HEADER_SIZE 7
33 #define CODEC2_MAGIC 0xC0DEC2
35 //the lowest version we should ever run across is 0.8
36 //we may run across later versions as the format evolves
37 #define EXPECTED_CODEC2_MAJOR_VERSION 0
38 #define EXPECTED_CODEC2_MINOR_VERSION 8
43 int frames_per_packet;
46 static int codec2_probe(const AVProbeData *p)
48 //must start wih C0 DE C2
49 if (AV_RB24(p->buf) != CODEC2_MAGIC) {
53 //no .c2 files prior to 0.8
54 //be strict about major version while we're at it
55 if (p->buf[3] != EXPECTED_CODEC2_MAJOR_VERSION ||
56 p->buf[4] < EXPECTED_CODEC2_MINOR_VERSION) {
60 //32 bits of identification -> low score
61 return AVPROBE_SCORE_EXTENSION + 1;
64 //Mimics codec2_samples_per_frame()
65 static int codec2_mode_frame_size(AVFormatContext *s, int mode)
67 int frame_size_table[CODEC2_MODE_MAX+1] = {
79 if (mode < 0 || mode > CODEC2_MODE_MAX) {
80 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find frame_size\n", mode);
83 return frame_size_table[mode];
87 //Mimics (codec2_bits_per_frame()+7)/8
88 static int codec2_mode_block_align(AVFormatContext *s, int mode)
90 int block_align_table[CODEC2_MODE_MAX+1] = {
102 if (mode < 0 || mode > CODEC2_MODE_MAX) {
103 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find block_align\n", mode);
106 return block_align_table[mode];
110 //Computes bitrate from mode, with frames rounded up to the nearest octet.
111 //So 700 bit/s (28 bits/frame) becomes 800 bits/s (32 bits/frame).
112 static int codec2_mode_bit_rate(AVFormatContext *s, int mode)
114 int frame_size = codec2_mode_frame_size(s, mode);
115 int block_align = codec2_mode_block_align(s, mode);
117 if (frame_size <= 0 || block_align <= 0) {
121 return 8 * 8000 * block_align / frame_size;
124 static int codec2_read_header_common(AVFormatContext *s, AVStream *st)
126 int mode = codec2_mode_from_extradata(st->codecpar->extradata);
128 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
129 st->codecpar->codec_id = AV_CODEC_ID_CODEC2;
130 st->codecpar->sample_rate = 8000;
131 st->codecpar->channels = 1;
132 st->codecpar->format = AV_SAMPLE_FMT_S16;
133 st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
134 st->codecpar->bit_rate = codec2_mode_bit_rate(s, mode);
135 st->codecpar->frame_size = codec2_mode_frame_size(s, mode);
136 st->codecpar->block_align = codec2_mode_block_align(s, mode);
138 if (st->codecpar->bit_rate <= 0 ||
139 st->codecpar->frame_size <= 0 ||
140 st->codecpar->block_align <= 0) {
141 return AVERROR_INVALIDDATA;
144 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
149 static int codec2_read_header(AVFormatContext *s)
151 AVStream *st = avformat_new_stream(s, NULL);
155 return AVERROR(ENOMEM);
158 if (avio_rb24(s->pb) != CODEC2_MAGIC) {
159 av_log(s, AV_LOG_ERROR, "not a .c2 file\n");
160 return AVERROR_INVALIDDATA;
163 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
168 ret = ffio_read_size(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
173 version = AV_RB16(st->codecpar->extradata);
174 if ((version >> 8) != EXPECTED_CODEC2_MAJOR_VERSION) {
175 avpriv_report_missing_feature(s, "Major version %i", version >> 8);
176 return AVERROR_PATCHWELCOME;
179 s->internal->data_offset = CODEC2_HEADER_SIZE;
181 return codec2_read_header_common(s, st);
184 static int codec2_read_packet(AVFormatContext *s, AVPacket *pkt)
186 Codec2Context *c2 = s->priv_data;
187 AVStream *st = s->streams[0];
188 int ret, size, n, block_align, frame_size;
190 block_align = st->codecpar->block_align;
191 frame_size = st->codecpar->frame_size;
193 if (block_align <= 0 || frame_size <= 0 || c2->frames_per_packet <= 0) {
194 return AVERROR(EINVAL);
197 //try to read desired number of frames, compute n from to actual number of bytes read
198 size = c2->frames_per_packet * block_align;
199 ret = av_get_packet(s->pb, pkt, size);
204 //only set duration - compute_pkt_fields() and ff_pcm_read_seek() takes care of everything else
205 //tested by spamming the seek functionality in ffplay
206 n = ret / block_align;
207 pkt->duration = n * frame_size;
212 static int codec2_write_header(AVFormatContext *s)
216 if (s->nb_streams != 1 || s->streams[0]->codecpar->codec_id != AV_CODEC_ID_CODEC2) {
217 av_log(s, AV_LOG_ERROR, ".c2 files must have exactly one codec2 stream\n");
218 return AVERROR(EINVAL);
223 if (st->codecpar->extradata_size != CODEC2_EXTRADATA_SIZE) {
224 av_log(s, AV_LOG_ERROR, ".c2 files require exactly %i bytes of extradata (got %i)\n",
225 CODEC2_EXTRADATA_SIZE, st->codecpar->extradata_size);
226 return AVERROR(EINVAL);
229 avio_wb24(s->pb, CODEC2_MAGIC);
230 avio_write(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
235 static int codec2raw_read_header(AVFormatContext *s)
237 Codec2Context *c2 = s->priv_data;
242 //FIXME: using a default value of -1 for mandatory options is an incredibly ugly hack
243 av_log(s, AV_LOG_ERROR, "-mode must be set in order to make sense of raw codec2 files\n");
244 return AVERROR(EINVAL);
247 st = avformat_new_stream(s, NULL);
249 return AVERROR(ENOMEM);
252 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
257 s->internal->data_offset = 0;
258 codec2_make_extradata(st->codecpar->extradata, c2->mode);
260 return codec2_read_header_common(s, st);
263 //transcoding report2074.c2 to wav went from 7.391s to 5.322s with -frames_per_packet 1000 compared to default, same sha1sum
264 #define FRAMES_PER_PACKET \
265 { "frames_per_packet", "Number of frames to read at a time. Higher = faster decoding, lower granularity", \
266 offsetof(Codec2Context, frames_per_packet), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM}
268 static const AVOption codec2_options[] = {
273 static const AVOption codec2raw_options[] = {
274 CODEC2_AVOPTIONS("codec2 mode [mandatory]", Codec2Context, -1, -1, AV_OPT_FLAG_DECODING_PARAM),
279 static const AVClass codec2_mux_class = {
280 .class_name = "codec2 muxer",
281 .item_name = av_default_item_name,
282 .version = LIBAVUTIL_VERSION_INT,
283 .category = AV_CLASS_CATEGORY_DEMUXER,
286 static const AVClass codec2_demux_class = {
287 .class_name = "codec2 demuxer",
288 .item_name = av_default_item_name,
289 .option = codec2_options,
290 .version = LIBAVUTIL_VERSION_INT,
291 .category = AV_CLASS_CATEGORY_DEMUXER,
294 static const AVClass codec2raw_demux_class = {
295 .class_name = "codec2raw demuxer",
296 .item_name = av_default_item_name,
297 .option = codec2raw_options,
298 .version = LIBAVUTIL_VERSION_INT,
299 .category = AV_CLASS_CATEGORY_DEMUXER,
302 #if CONFIG_CODEC2_DEMUXER
303 AVInputFormat ff_codec2_demuxer = {
305 .long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 demuxer"),
306 .priv_data_size = sizeof(Codec2Context),
308 .read_probe = codec2_probe,
309 .read_header = codec2_read_header,
310 .read_packet = codec2_read_packet,
311 .read_seek = ff_pcm_read_seek,
312 .flags = AVFMT_GENERIC_INDEX,
313 .raw_codec_id = AV_CODEC_ID_CODEC2,
314 .priv_class = &codec2_demux_class,
318 #if CONFIG_CODEC2_MUXER
319 AVOutputFormat ff_codec2_muxer = {
321 .long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 muxer"),
322 .priv_data_size = sizeof(Codec2Context),
324 .audio_codec = AV_CODEC_ID_CODEC2,
325 .video_codec = AV_CODEC_ID_NONE,
326 .write_header = codec2_write_header,
327 .write_packet = ff_raw_write_packet,
328 .flags = AVFMT_NOTIMESTAMPS,
329 .priv_class = &codec2_mux_class,
333 #if CONFIG_CODEC2RAW_DEMUXER
334 AVInputFormat ff_codec2raw_demuxer = {
336 .long_name = NULL_IF_CONFIG_SMALL("raw codec2 demuxer"),
337 .priv_data_size = sizeof(Codec2Context),
338 .read_header = codec2raw_read_header,
339 .read_packet = codec2_read_packet,
340 .read_seek = ff_pcm_read_seek,
341 .flags = AVFMT_GENERIC_INDEX,
342 .raw_codec_id = AV_CODEC_ID_CODEC2,
343 .priv_class = &codec2raw_demux_class,