libavformat/mpc8.c

   1 /*
   2  * Musepack SV8 demuxer
   3  * Copyright (c) 2007 Konstantin Shishkov
   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 "libavcodec/get_bits.h"
  23 #include "libavcodec/unary.h"
  24 #include "apetag.h"
  25 #include "avformat.h"
  26 #include "internal.h"
  27 #include "avio_internal.h"
  28
  29 /// Two-byte MPC tag
  30 #define MKMPCTAG(a, b) ((a) | ((b) << 8))
  31
  32 #define TAG_MPCK MKTAG('M','P','C','K')
  33
  34 /// Reserved MPC tags
  35 enum MPCPacketTags{
  36     TAG_STREAMHDR   = MKMPCTAG('S','H'),
  37     TAG_STREAMEND   = MKMPCTAG('S','E'),
  38
  39     TAG_AUDIOPACKET = MKMPCTAG('A','P'),
  40
  41     TAG_SEEKTBLOFF  = MKMPCTAG('S','O'),
  42     TAG_SEEKTABLE   = MKMPCTAG('S','T'),
  43
  44     TAG_REPLAYGAIN  = MKMPCTAG('R','G'),
  45     TAG_ENCINFO     = MKMPCTAG('E','I'),
  46 };
  47
  48 static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 };
  49
  50 typedef struct MPCContext {
  51     int ver;
  52     int64_t header_pos;
  53     int64_t samples;
  54
  55     int64_t apetag_start;
  56 } MPCContext;
  57
  58 static inline int64_t bs_get_v(const uint8_t **bs)
  59 {
  60     uint64_t v = 0;
  61     int br = 0;
  62     int c;
  63
  64     do {
  65         c = **bs; (*bs)++;
  66         v <<= 7;
  67         v |= c & 0x7F;
  68         br++;
  69         if (br > 10)
  70             return -1;
  71     } while (c & 0x80);
  72
  73     return v - br;
  74 }
  75
  76 static int mpc8_probe(const AVProbeData *p)
  77 {
  78     const uint8_t *bs = p->buf + 4;
  79     const uint8_t *bs_end = bs + p->buf_size;
  80     int64_t size;
  81
  82     if (p->buf_size < 16)
  83         return 0;
  84     if (AV_RL32(p->buf) != TAG_MPCK)
  85         return 0;
  86     while (bs < bs_end + 3) {
  87         int header_found = (bs[0] == 'S' && bs[1] == 'H');
  88         if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z')
  89             return 0;
  90         bs += 2;
  91         size = bs_get_v(&bs);
  92         if (size < 2)
  93             return 0;
  94         if (size >= bs_end - bs + 2)
  95             return AVPROBE_SCORE_EXTENSION - 1; // seems to be valid MPC but no header yet
  96         if (header_found) {
  97             if (size < 11 || size > 28)
  98                 return 0;
  99             if (!AV_RL32(bs)) //zero CRC is invalid
 100                 return 0;
 101             return AVPROBE_SCORE_MAX;
 102         } else {
 103             bs += size - 2;
 104         }
 105     }
 106     return 0;
 107 }
 108
 109 static inline int64_t gb_get_v(GetBitContext *gb)
 110 {
 111     uint64_t v = 0;
 112     int bits = 0;
 113     while(get_bits1(gb) && bits < 64-7){
 114         v <<= 7;
 115         v |= get_bits(gb, 7);
 116         bits += 7;
 117     }
 118     v <<= 7;
 119     v |= get_bits(gb, 7);
 120
 121     return v;
 122 }
 123
 124 static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)
 125 {
 126     int64_t pos;
 127     pos = avio_tell(pb);
 128     *tag = avio_rl16(pb);
 129     *size = ffio_read_varlen(pb);
 130     pos -= avio_tell(pb);
 131     if (av_sat_add64(*size, pos) != (uint64_t)*size + pos) {
 132         *size = -1;
 133     } else
 134         *size += pos;
 135 }
 136
 137 static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
 138 {
 139     MPCContext *c = s->priv_data;
 140     int tag;
 141     int64_t size, pos, ppos[2];
 142     uint8_t *buf;
 143     int i, t, seekd, ret;
 144     GetBitContext gb;
 145
 146     if (s->nb_streams == 0) {
 147         av_log(s, AV_LOG_ERROR, "No stream added before parsing seek table\n");
 148         return;
 149     }
 150
 151     avio_seek(s->pb, off, SEEK_SET);
 152     mpc8_get_chunk_header(s->pb, &tag, &size);
 153     if(tag != TAG_SEEKTABLE){
 154         av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
 155         return;
 156     }
 157     if (size > INT_MAX/10 || size<=0) {
 158         av_log(s, AV_LOG_ERROR, "Bad seek table size\n");
 159         return;
 160     }
 161     if(!(buf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE)))
 162         return;
 163     ret = avio_read(s->pb, buf, size);
 164     if (ret != size) {
 165         av_log(s, AV_LOG_ERROR, "seek table truncated\n");
 166         av_free(buf);
 167         return;
 168     }
 169     memset(buf+size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 170
 171     init_get_bits(&gb, buf, size * 8);
 172     size = gb_get_v(&gb);
 173     if(size > UINT_MAX/4 || size > c->samples/1152){
 174         av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
 175         av_free(buf);
 176         return;
 177     }
 178     seekd = get_bits(&gb, 4);
 179     for(i = 0; i < 2; i++){
 180         pos = gb_get_v(&gb);
 181         if (av_sat_add64(pos, c->header_pos) != pos + (uint64_t)c->header_pos) {
 182             av_free(buf);
 183             return;
 184         }
 185
 186         pos += c->header_pos;
 187         ppos[1 - i] = pos;
 188         av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
 189     }
 190     for(; i < size; i++){
 191         if (get_bits_left(&gb) < 13) {
 192             av_free(buf);
 193             return;
 194         }
 195         t = get_unary(&gb, 1, 33) << 12;
 196         t += get_bits(&gb, 12);
 197         if(t & 1)
 198             t = -(t & ~1);
 199         pos = (t >> 1) + (uint64_t)ppos[0]*2 - ppos[1];
 200         av_add_index_entry(s->streams[0], pos, (int64_t)i << seekd, 0, 0, AVINDEX_KEYFRAME);
 201         ppos[1] = ppos[0];
 202         ppos[0] = pos;
 203     }
 204     av_free(buf);
 205 }
 206
 207 static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
 208 {
 209     AVIOContext *pb = s->pb;
 210     int64_t pos, off;
 211
 212     switch(tag){
 213     case TAG_SEEKTBLOFF:
 214         pos = avio_tell(pb);
 215         off = ffio_read_varlen(pb);
 216         if (pos > INT64_MAX - size || off < 0 || off > INT64_MAX - chunk_pos)
 217             return;
 218         pos += size;
 219         mpc8_parse_seektable(s, chunk_pos + off);
 220         avio_seek(pb, pos, SEEK_SET);
 221         break;
 222     default:
 223         avio_skip(pb, size);
 224     }
 225 }
 226
 227 static int mpc8_read_header(AVFormatContext *s)
 228 {
 229     MPCContext *c = s->priv_data;
 230     AVIOContext *pb = s->pb;
 231     AVStream *st;
 232     int tag = 0, ret;
 233     int64_t size, pos;
 234
 235     c->header_pos = avio_tell(pb);
 236     if(avio_rl32(pb) != TAG_MPCK){
 237         av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
 238         return AVERROR_INVALIDDATA;
 239     }
 240
 241     while(!avio_feof(pb)){
 242         pos = avio_tell(pb);
 243         mpc8_get_chunk_header(pb, &tag, &size);
 244         if (size < 0) {
 245             av_log(s, AV_LOG_ERROR, "Invalid chunk length\n");
 246             return AVERROR_INVALIDDATA;
 247         }
 248         if(tag == TAG_STREAMHDR)
 249             break;
 250         mpc8_handle_chunk(s, tag, pos, size);
 251     }
 252     if(tag != TAG_STREAMHDR){
 253         av_log(s, AV_LOG_ERROR, "Stream header not found\n");
 254         return AVERROR_INVALIDDATA;
 255     }
 256     pos = avio_tell(pb);
 257     avio_skip(pb, 4); //CRC
 258     c->ver = avio_r8(pb);
 259     if(c->ver != 8){
 260         avpriv_report_missing_feature(s, "Stream version %d", c->ver);
 261         return AVERROR_PATCHWELCOME;
 262     }
 263     c->samples = ffio_read_varlen(pb);
 264     ffio_read_varlen(pb); //silence samples at the beginning
 265
 266     st = avformat_new_stream(s, NULL);
 267     if (!st)
 268         return AVERROR(ENOMEM);
 269     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 270     st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK8;
 271     st->codecpar->bits_per_coded_sample = 16;
 272
 273     if ((ret = ff_get_extradata(s, st->codecpar, pb, 2)) < 0)
 274         return ret;
 275
 276     st->codecpar->channels = (st->codecpar->extradata[1] >> 4) + 1;
 277     st->codecpar->sample_rate = mpc8_rate[st->codecpar->extradata[0] >> 5];
 278     avpriv_set_pts_info(st, 64, 1152  << (st->codecpar->extradata[1]&3)*2, st->codecpar->sample_rate);
 279     st->start_time = 0;
 280     st->duration = c->samples / (1152 << (st->codecpar->extradata[1]&3)*2);
 281     size -= avio_tell(pb) - pos;
 282     if (size > 0)
 283         avio_skip(pb, size);
 284
 285     if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
 286         int64_t pos = avio_tell(s->pb);
 287         c->apetag_start = ff_ape_parse_tag(s);
 288         avio_seek(s->pb, pos, SEEK_SET);
 289     }
 290
 291     return 0;
 292 }
 293
 294 static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
 295 {
 296     MPCContext *c = s->priv_data;
 297     int tag, ret;
 298     int64_t pos, size;
 299
 300     while(!avio_feof(s->pb)){
 301         pos = avio_tell(s->pb);
 302
 303         /* don't return bogus packets with the ape tag data */
 304         if (c->apetag_start && pos >= c->apetag_start)
 305             return AVERROR_EOF;
 306
 307         mpc8_get_chunk_header(s->pb, &tag, &size);
 308         if (size < 0 || size > INT_MAX)
 309             return -1;
 310         if(tag == TAG_AUDIOPACKET){
 311             if ((ret = av_get_packet(s->pb, pkt, size)) < 0)
 312                 return ret;
 313             pkt->stream_index = 0;
 314             pkt->duration     = 1;
 315             return 0;
 316         }
 317         if(tag == TAG_STREAMEND)
 318             return AVERROR_EOF;
 319         mpc8_handle_chunk(s, tag, pos, size);
 320     }
 321     return AVERROR_EOF;
 322 }
 323
 324 static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 325 {
 326     AVStream *st = s->streams[stream_index];
 327     int index = av_index_search_timestamp(st, timestamp, flags);
 328
 329     if(index < 0) return -1;
 330     if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
 331         return -1;
 332     ff_update_cur_dts(s, st, st->index_entries[index].timestamp);
 333     return 0;
 334 }
 335
 336
 337 AVInputFormat ff_mpc8_demuxer = {
 338     .name           = "mpc8",
 339     .long_name      = NULL_IF_CONFIG_SMALL("Musepack SV8"),
 340     .priv_data_size = sizeof(MPCContext),
 341     .read_probe     = mpc8_probe,
 342     .read_header    = mpc8_read_header,
 343     .read_packet    = mpc8_read_packet,
 344     .read_seek      = mpc8_read_seek,
 345 };