libavformat/mpc.c

   1 /*
   2  * Musepack demuxer
   3  * Copyright (c) 2006 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 #include "libavcodec/get_bits.h"
  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 {
  35     int64_t pos;
  36     int size, skip;
  37 }MPCFrame;
  38
  39 typedef struct {
  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         return AVERROR(ENOMEM);
  92     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  93     st->codec->codec_id = AV_CODEC_ID_MUSEPACK7;
  94     st->codec->channels = 2;
  95     st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
  96     st->codec->bits_per_coded_sample = 16;
  97
  98     st->codec->extradata_size = 16;
  99     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
 100     avio_read(s->pb, st->codec->extradata, 16);
 101     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
 102     avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
 103     /* scan for seekpoints */
 104     st->start_time = 0;
 105     st->duration = c->fcount;
 106
 107     /* try to read APE tags */
 108     if (s->pb->seekable) {
 109         int64_t pos = avio_tell(s->pb);
 110         ff_ape_parse_tag(s);
 111         if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
 112             ff_id3v1_read(s);
 113         avio_seek(s->pb, pos, SEEK_SET);
 114     }
 115
 116     return 0;
 117 }
 118
 119 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 120 {
 121     MPCContext *c = s->priv_data;
 122     int ret, size, size2, curbits, cur = c->curframe;
 123     unsigned tmp;
 124     int64_t pos;
 125
 126     if (c->curframe >= c->fcount && c->fcount)
 127         return AVERROR_EOF;
 128
 129     if(c->curframe != c->lastframe + 1){
 130         avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
 131         c->curbits = c->frames[c->curframe].skip;
 132     }
 133     c->lastframe = c->curframe;
 134     c->curframe++;
 135     curbits = c->curbits;
 136     pos = avio_tell(s->pb);
 137     tmp = avio_rl32(s->pb);
 138     if(curbits <= 12){
 139         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
 140     }else{
 141         size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
 142     }
 143     curbits += 20;
 144     avio_seek(s->pb, pos, SEEK_SET);
 145
 146     size = ((size2 + curbits + 31) & ~31) >> 3;
 147     if(cur == c->frames_noted && c->fcount){
 148         c->frames[cur].pos = pos;
 149         c->frames[cur].size = size;
 150         c->frames[cur].skip = curbits - 20;
 151         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
 152         c->frames_noted++;
 153     }
 154     c->curbits = (curbits + size2) & 0x1F;
 155
 156     if ((ret = av_new_packet(pkt, size)) < 0)
 157         return ret;
 158
 159     pkt->data[0] = curbits;
 160     pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
 161     pkt->data[2] = 0;
 162     pkt->data[3] = 0;
 163
 164     pkt->stream_index = 0;
 165     pkt->pts = cur;
 166     ret = avio_read(s->pb, pkt->data + 4, size);
 167     if(c->curbits)
 168         avio_seek(s->pb, -4, SEEK_CUR);
 169     if(ret < size){
 170         av_free_packet(pkt);
 171         return ret < 0 ? ret : AVERROR(EIO);
 172     }
 173     pkt->size = ret + 4;
 174
 175     return 0;
 176 }
 177
 178 static int mpc_read_close(AVFormatContext *s)
 179 {
 180     MPCContext *c = s->priv_data;
 181
 182     av_freep(&c->frames);
 183     return 0;
 184 }
 185
 186 /**
 187  * Seek to the given position
 188  * If position is unknown but is within the limits of file
 189  * then packets are skipped unless desired position is reached
 190  *
 191  * Also this function makes use of the fact that timestamp == frameno
 192  */
 193 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 194 {
 195     AVStream *st = s->streams[stream_index];
 196     MPCContext *c = s->priv_data;
 197     AVPacket pkt1, *pkt = &pkt1;
 198     int ret;
 199     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
 200     uint32_t lastframe;
 201
 202     /* if found, seek there */
 203     if (index >= 0){
 204         c->curframe = st->index_entries[index].pos;
 205         return 0;
 206     }
 207     /* if timestamp is out of bounds, return error */
 208     if(timestamp < 0 || timestamp >= c->fcount)
 209         return -1;
 210     timestamp -= DELAY_FRAMES;
 211     /* seek to the furthest known position and read packets until
 212        we reach desired position */
 213     lastframe = c->curframe;
 214     if(c->frames_noted) c->curframe = c->frames_noted - 1;
 215     while(c->curframe < timestamp){
 216         ret = av_read_frame(s, pkt);
 217         if (ret < 0){
 218             c->curframe = lastframe;
 219             return ret;
 220         }
 221         av_free_packet(pkt);
 222     }
 223     return 0;
 224 }
 225
 226
 227 AVInputFormat ff_mpc_demuxer = {
 228     .name           = "mpc",
 229     .long_name      = NULL_IF_CONFIG_SMALL("Musepack"),
 230     .priv_data_size = sizeof(MPCContext),
 231     .read_probe     = mpc_probe,
 232     .read_header    = mpc_read_header,
 233     .read_packet    = mpc_read_packet,
 234     .read_close     = mpc_read_close,
 235     .read_seek      = mpc_read_seek,
 236     .extensions     = "mpc",
 237 };