libavformat/mpc.c

   1 /*
   2  * Musepack demuxer
   3  * Copyright (c) 2006 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 "libavutil/channel_layout.h"
  23
  24 #include "avformat.h"
  25 #include "internal.h"
  26 #include "apetag.h"
  27 #include "id3v1.h"
  28 #include "libavutil/dict.h"
  29
  30 #define MPC_FRAMESIZE  1152
  31 #define DELAY_FRAMES   32
  32
  33 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
  34 typedef struct MPCFrame {
  35     int64_t pos;
  36     int size, skip;
  37 }MPCFrame;
  38
  39 typedef struct MPCContext {
  40     int ver;
  41     uint32_t curframe, lastframe;
  42     uint32_t fcount;
  43     MPCFrame *frames;
  44     int curbits;
  45     int frames_noted;
  46 } MPCContext;
  47
  48 static int mpc_probe(AVProbeData *p)
  49 {
  50     const uint8_t *d = p->buf;
  51     if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
  52         return AVPROBE_SCORE_MAX;
  53     return 0;
  54 }
  55
  56 static int mpc_read_header(AVFormatContext *s)
  57 {
  58     MPCContext *c = s->priv_data;
  59     AVStream *st;
  60
  61     if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
  62         av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  63         return AVERROR_INVALIDDATA;
  64     }
  65     c->ver = avio_r8(s->pb);
  66     if(c->ver != 0x07 && c->ver != 0x17){
  67         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
  68         return AVERROR_INVALIDDATA;
  69     }
  70     c->fcount = avio_rl32(s->pb);
  71     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
  72         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
  73         return AVERROR_INVALIDDATA;
  74     }
  75     if(c->fcount){
  76         c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
  77         if(!c->frames){
  78             av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
  79             return AVERROR(ENOMEM);
  80         }
  81     }else{
  82         av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
  83     }
  84     c->curframe = 0;
  85     c->lastframe = -1;
  86     c->curbits = 8;
  87     c->frames_noted = 0;
  88
  89     st = avformat_new_stream(s, NULL);
  90     if (!st)
  91         goto mem_error;
  92     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
  93     st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK7;
  94     st->codecpar->channels = 2;
  95     st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
  96     st->codecpar->bits_per_coded_sample = 16;
  97
  98     if (ff_get_extradata(s, st->codecpar, s->pb, 16) < 0)
  99         goto mem_error;
 100     st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
 101     avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codecpar->sample_rate);
 102     /* scan for seekpoints */
 103     st->start_time = 0;
 104     st->duration = c->fcount;
 105
 106     /* try to read APE tags */
 107     if (s->pb->seekable) {
 108         int64_t pos = avio_tell(s->pb);
 109         ff_ape_parse_tag(s);
 110         if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
 111             ff_id3v1_read(s);
 112         avio_seek(s->pb, pos, SEEK_SET);
 113     }
 114
 115     return 0;
 116 mem_error:
 117     av_freep(&c->frames);
 118     return AVERROR(ENOMEM);
 119 }
 120
 121 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 122 {
 123     MPCContext *c = s->priv_data;
 124     int ret, size, size2, curbits, cur = c->curframe;
 125     unsigned tmp;
 126     int64_t pos;
 127
 128     if (c->curframe >= c->fcount && c->fcount)
 129         return AVERROR_EOF;
 130
 131     if(c->curframe != c->lastframe + 1){
 132         avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
 133         c->curbits = c->frames[c->curframe].skip;
 134     }
 135     c->lastframe = c->curframe;
 136     c->curframe++;
 137     curbits = c->curbits;
 138     pos = avio_tell(s->pb);
 139     tmp = avio_rl32(s->pb);
 140     if(curbits <= 12){
 141         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
 142     }else{
 143         size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
 144     }
 145     curbits += 20;
 146     avio_seek(s->pb, pos, SEEK_SET);
 147
 148     size = ((size2 + curbits + 31) & ~31) >> 3;
 149     if(cur == c->frames_noted && c->fcount){
 150         c->frames[cur].pos = pos;
 151         c->frames[cur].size = size;
 152         c->frames[cur].skip = curbits - 20;
 153         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
 154         c->frames_noted++;
 155     }
 156     c->curbits = (curbits + size2) & 0x1F;
 157
 158     if ((ret = av_new_packet(pkt, size + 4)) < 0)
 159         return ret;
 160
 161     pkt->data[0] = curbits;
 162     pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
 163     pkt->data[2] = 0;
 164     pkt->data[3] = 0;
 165
 166     pkt->stream_index = 0;
 167     pkt->pts = cur;
 168     ret = avio_read(s->pb, pkt->data + 4, size);
 169     if(c->curbits)
 170         avio_seek(s->pb, -4, SEEK_CUR);
 171     if(ret < size){
 172         av_packet_unref(pkt);
 173         return ret < 0 ? ret : AVERROR(EIO);
 174     }
 175     pkt->size = ret + 4;
 176
 177     return 0;
 178 }
 179
 180 static int mpc_read_close(AVFormatContext *s)
 181 {
 182     MPCContext *c = s->priv_data;
 183
 184     av_freep(&c->frames);
 185     return 0;
 186 }
 187
 188 /**
 189  * Seek to the given position
 190  * If position is unknown but is within the limits of file
 191  * then packets are skipped unless desired position is reached
 192  *
 193  * Also this function makes use of the fact that timestamp == frameno
 194  */
 195 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 196 {
 197     AVStream *st = s->streams[stream_index];
 198     MPCContext *c = s->priv_data;
 199     AVPacket pkt1, *pkt = &pkt1;
 200     int ret;
 201     int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
 202     uint32_t lastframe;
 203
 204     /* if found, seek there */
 205     if (index >= 0 && st->index_entries[st->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES){
 206         c->curframe = st->index_entries[index].pos;
 207         return 0;
 208     }
 209     /* if timestamp is out of bounds, return error */
 210     if(timestamp < 0 || timestamp >= c->fcount)
 211         return -1;
 212     timestamp -= DELAY_FRAMES;
 213     /* seek to the furthest known position and read packets until
 214        we reach desired position */
 215     lastframe = c->curframe;
 216     if(c->frames_noted) c->curframe = c->frames_noted - 1;
 217     while(c->curframe < timestamp){
 218         ret = av_read_frame(s, pkt);
 219         if (ret < 0){
 220             c->curframe = lastframe;
 221             return ret;
 222         }
 223         av_packet_unref(pkt);
 224     }
 225     return 0;
 226 }
 227
 228
 229 AVInputFormat ff_mpc_demuxer = {
 230     .name           = "mpc",
 231     .long_name      = NULL_IF_CONFIG_SMALL("Musepack"),
 232     .priv_data_size = sizeof(MPCContext),
 233     .read_probe     = mpc_probe,
 234     .read_header    = mpc_read_header,
 235     .read_packet    = mpc_read_packet,
 236     .read_close     = mpc_read_close,
 237     .read_seek      = mpc_read_seek,
 238     .extensions     = "mpc",
 239 };