libavformat/codec2.c

   1 /*
   2  * codec2 muxer and demuxers
   3  * Copyright (c) 2017 Tomas Härdin
   4  *
   5  * This file is part of FFmpeg.
   6  *
   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.
  11  *
  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.
  16  *
  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
  20  */
  21
  22 #include "config_components.h"
  23
  24 #include "libavcodec/codec2utils.h"
  25 #include "libavutil/channel_layout.h"
  26 #include "libavutil/intreadwrite.h"
  27 #include "libavutil/opt.h"
  28 #include "avio_internal.h"
  29 #include "avformat.h"
  30 #include "demux.h"
  31 #include "internal.h"
  32 #include "mux.h"
  33 #include "rawenc.h"
  34 #include "pcm.h"
  35
  36 #define CODEC2_HEADER_SIZE 7
  37 #define CODEC2_MAGIC       0xC0DEC2
  38
  39 //the lowest version we should ever run across is 0.8
  40 //we may run across later versions as the format evolves
  41 #define EXPECTED_CODEC2_MAJOR_VERSION 0
  42 #define EXPECTED_CODEC2_MINOR_VERSION 8
  43
  44 typedef struct {
  45     const AVClass *class;
  46     int mode;
  47     int frames_per_packet;
  48 } Codec2Context;
  49
  50 static int codec2_probe(const AVProbeData *p)
  51 {
  52     //must start wih C0 DE C2
  53     if (AV_RB24(p->buf) != CODEC2_MAGIC) {
  54         return 0;
  55     }
  56
  57     //no .c2 files prior to 0.8
  58     //be strict about major version while we're at it
  59     if (p->buf[3] != EXPECTED_CODEC2_MAJOR_VERSION ||
  60         p->buf[4] <  EXPECTED_CODEC2_MINOR_VERSION) {
  61         return 0;
  62     }
  63
  64     //32 bits of identification -> low score
  65     return AVPROBE_SCORE_EXTENSION + 1;
  66 }
  67
  68 //Mimics codec2_samples_per_frame()
  69 static int codec2_mode_frame_size(AVFormatContext *s, int mode)
  70 {
  71     int frame_size_table[CODEC2_MODE_MAX+1] = {
  72         160,    // 3200
  73         160,    // 2400
  74         320,    // 1600
  75         320,    // 1400
  76         320,    // 1300
  77         320,    // 1200
  78         320,    // 700
  79         320,    // 700B
  80         320,    // 700C
  81     };
  82
  83     if (mode < 0 || mode > CODEC2_MODE_MAX) {
  84         av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find frame_size\n", mode);
  85         return 0;
  86     } else {
  87         return frame_size_table[mode];
  88     }
  89 }
  90
  91 //Mimics (codec2_bits_per_frame()+7)/8
  92 static int codec2_mode_block_align(AVFormatContext *s, int mode)
  93 {
  94     int block_align_table[CODEC2_MODE_MAX+1] = {
  95         8,      // 3200
  96         6,      // 2400
  97         8,      // 1600
  98         7,      // 1400
  99         7,      // 1300
 100         6,      // 1200
 101         4,      // 700
 102         4,      // 700B
 103         4,      // 700C
 104     };
 105
 106     if (mode < 0 || mode > CODEC2_MODE_MAX) {
 107         av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find block_align\n", mode);
 108         return 0;
 109     } else {
 110         return block_align_table[mode];
 111     }
 112 }
 113
 114 //Computes bitrate from mode, with frames rounded up to the nearest octet.
 115 //So 700 bit/s (28 bits/frame) becomes 800 bits/s (32 bits/frame).
 116 static int codec2_mode_bit_rate(AVFormatContext *s, int mode)
 117 {
 118     int frame_size  = codec2_mode_frame_size(s, mode);
 119     int block_align = codec2_mode_block_align(s, mode);
 120
 121     if (frame_size <= 0 || block_align <= 0) {
 122         return 0;
 123     }
 124
 125     return 8 * 8000 * block_align / frame_size;
 126 }
 127
 128 static int codec2_read_header_common(AVFormatContext *s, AVStream *st)
 129 {
 130     int mode = codec2_mode_from_extradata(st->codecpar->extradata);
 131
 132     st->codecpar->codec_type        = AVMEDIA_TYPE_AUDIO;
 133     st->codecpar->codec_id          = AV_CODEC_ID_CODEC2;
 134     st->codecpar->sample_rate       = 8000;
 135     st->codecpar->format            = AV_SAMPLE_FMT_S16;
 136     st->codecpar->ch_layout         = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
 137     st->codecpar->bit_rate          = codec2_mode_bit_rate(s, mode);
 138     st->codecpar->frame_size        = codec2_mode_frame_size(s, mode);
 139     st->codecpar->block_align       = codec2_mode_block_align(s, mode);
 140
 141     if (st->codecpar->bit_rate <= 0 ||
 142         st->codecpar->frame_size <= 0 ||
 143         st->codecpar->block_align <= 0) {
 144         return AVERROR_INVALIDDATA;
 145     }
 146
 147     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
 148
 149     return 0;
 150 }
 151
 152 static int codec2_read_header(AVFormatContext *s)
 153 {
 154     AVStream *st = avformat_new_stream(s, NULL);
 155     int ret, version;
 156
 157     if (!st) {
 158         return AVERROR(ENOMEM);
 159     }
 160
 161     if (avio_rb24(s->pb) != CODEC2_MAGIC) {
 162         av_log(s, AV_LOG_ERROR, "not a .c2 file\n");
 163         return AVERROR_INVALIDDATA;
 164     }
 165
 166     ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
 167     if (ret) {
 168         return ret;
 169     }
 170
 171     ret = ffio_read_size(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
 172     if (ret < 0) {
 173         return ret;
 174     }
 175
 176     version = AV_RB16(st->codecpar->extradata);
 177     if ((version >> 8) != EXPECTED_CODEC2_MAJOR_VERSION) {
 178         avpriv_report_missing_feature(s, "Major version %i", version >> 8);
 179         return AVERROR_PATCHWELCOME;
 180     }
 181
 182     ffformatcontext(s)->data_offset = CODEC2_HEADER_SIZE;
 183
 184     return codec2_read_header_common(s, st);
 185 }
 186
 187 static int codec2_read_packet(AVFormatContext *s, AVPacket *pkt)
 188 {
 189     Codec2Context *c2 = s->priv_data;
 190     AVStream *st = s->streams[0];
 191     int ret, size, n, block_align, frame_size;
 192
 193     block_align = st->codecpar->block_align;
 194     frame_size  = st->codecpar->frame_size;
 195
 196     if (block_align <= 0 || frame_size <= 0 || c2->frames_per_packet <= 0) {
 197         return AVERROR(EINVAL);
 198     }
 199
 200     //try to read desired number of frames, compute n from to actual number of bytes read
 201     size = c2->frames_per_packet * block_align;
 202     ret = av_get_packet(s->pb, pkt, size);
 203     if (ret < 0) {
 204         return ret;
 205     }
 206
 207     //only set duration - compute_pkt_fields() and ff_pcm_read_seek() takes care of everything else
 208     //tested by spamming the seek functionality in ffplay
 209     n = ret / block_align;
 210     pkt->duration = n * frame_size;
 211
 212     return ret;
 213 }
 214
 215 static int codec2_write_header(AVFormatContext *s)
 216 {
 217     AVStream *st = s->streams[0];
 218
 219     if (st->codecpar->extradata_size != CODEC2_EXTRADATA_SIZE) {
 220         av_log(s, AV_LOG_ERROR, ".c2 files require exactly %i bytes of extradata (got %i)\n",
 221                CODEC2_EXTRADATA_SIZE, st->codecpar->extradata_size);
 222         return AVERROR(EINVAL);
 223     }
 224
 225     avio_wb24(s->pb, CODEC2_MAGIC);
 226     avio_write(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
 227
 228     return 0;
 229 }
 230
 231 static int codec2raw_read_header(AVFormatContext *s)
 232 {
 233     Codec2Context *c2 = s->priv_data;
 234     AVStream *st;
 235     int ret;
 236
 237     if (c2->mode < 0) {
 238         //FIXME: using a default value of -1 for mandatory options is an incredibly ugly hack
 239         av_log(s, AV_LOG_ERROR, "-mode must be set in order to make sense of raw codec2 files\n");
 240         return AVERROR(EINVAL);
 241     }
 242
 243     st = avformat_new_stream(s, NULL);
 244     if (!st) {
 245         return AVERROR(ENOMEM);
 246     }
 247
 248     ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
 249     if (ret) {
 250         return ret;
 251     }
 252
 253     codec2_make_extradata(st->codecpar->extradata, c2->mode);
 254
 255     return codec2_read_header_common(s, st);
 256 }
 257
 258 //transcoding report2074.c2 to wav went from 7.391s to 5.322s with -frames_per_packet 1000 compared to default, same sha1sum
 259 #define FRAMES_PER_PACKET \
 260     { "frames_per_packet", "Number of frames to read at a time. Higher = faster decoding, lower granularity", \
 261       offsetof(Codec2Context, frames_per_packet), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM}
 262
 263 static const AVOption codec2_options[] = {
 264     FRAMES_PER_PACKET,
 265     { NULL },
 266 };
 267
 268 static const AVOption codec2raw_options[] = {
 269     CODEC2_AVOPTIONS("codec2 mode [mandatory]", Codec2Context, -1, -1, AV_OPT_FLAG_DECODING_PARAM),
 270     FRAMES_PER_PACKET,
 271     { NULL },
 272 };
 273
 274 static const AVClass codec2_demux_class = {
 275     .class_name = "codec2 demuxer",
 276     .item_name  = av_default_item_name,
 277     .option     = codec2_options,
 278     .version    = LIBAVUTIL_VERSION_INT,
 279     .category   = AV_CLASS_CATEGORY_DEMUXER,
 280 };
 281
 282 static const AVClass codec2raw_demux_class = {
 283     .class_name = "codec2raw demuxer",
 284     .item_name  = av_default_item_name,
 285     .option     = codec2raw_options,
 286     .version    = LIBAVUTIL_VERSION_INT,
 287     .category   = AV_CLASS_CATEGORY_DEMUXER,
 288 };
 289
 290 #if CONFIG_CODEC2_DEMUXER
 291 const FFInputFormat ff_codec2_demuxer = {
 292     .p.name         = "codec2",
 293     .p.long_name    = NULL_IF_CONFIG_SMALL("codec2 .c2 demuxer"),
 294     .p.extensions   = "c2",
 295     .p.flags        = AVFMT_GENERIC_INDEX,
 296     .p.priv_class   = &codec2_demux_class,
 297     .priv_data_size = sizeof(Codec2Context),
 298     .read_probe     = codec2_probe,
 299     .read_header    = codec2_read_header,
 300     .read_packet    = codec2_read_packet,
 301     .read_seek      = ff_pcm_read_seek,
 302     .raw_codec_id   = AV_CODEC_ID_CODEC2,
 303 };
 304 #endif
 305
 306 #if CONFIG_CODEC2_MUXER
 307 const FFOutputFormat ff_codec2_muxer = {
 308     .p.name         = "codec2",
 309     .p.long_name    = NULL_IF_CONFIG_SMALL("codec2 .c2 muxer"),
 310     .p.extensions   = "c2",
 311     .p.audio_codec  = AV_CODEC_ID_CODEC2,
 312     .p.video_codec  = AV_CODEC_ID_NONE,
 313     .p.subtitle_codec = AV_CODEC_ID_NONE,
 314     .p.flags        = AVFMT_NOTIMESTAMPS,
 315     .flags_internal   = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
 316                         FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
 317     .write_header   = codec2_write_header,
 318     .write_packet   = ff_raw_write_packet,
 319 };
 320 #endif
 321
 322 #if CONFIG_CODEC2RAW_DEMUXER
 323 const FFInputFormat ff_codec2raw_demuxer = {
 324     .p.name         = "codec2raw",
 325     .p.long_name    = NULL_IF_CONFIG_SMALL("raw codec2 demuxer"),
 326     .p.flags        = AVFMT_GENERIC_INDEX,
 327     .p.priv_class   = &codec2raw_demux_class,
 328     .priv_data_size = sizeof(Codec2Context),
 329     .read_header    = codec2raw_read_header,
 330     .read_packet    = codec2_read_packet,
 331     .read_seek      = ff_pcm_read_seek,
 332     .raw_codec_id   = AV_CODEC_ID_CODEC2,
 333 };
 334 #endif