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 "libavcodec/get_bits.h"
  23 #include "avformat.h"
  24 #include "id3v2.h"
  25
  26 #define MPC_FRAMESIZE  1152
  27 #define DELAY_FRAMES   32
  28
  29 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
  30 typedef struct {
  31     int64_t pos;
  32     int size, skip;
  33 }MPCFrame;
  34
  35 typedef struct {
  36     int ver;
  37     uint32_t curframe, lastframe;
  38     uint32_t fcount;
  39     MPCFrame *frames;
  40     int curbits;
  41     int frames_noted;
  42 } MPCContext;
  43
  44 static int mpc_probe(AVProbeData *p)
  45 {
  46     const uint8_t *d = p->buf;
  47     if (ff_id3v2_match(d)) {
  48         d += ff_id3v2_tag_len(d);
  49     }
  50     if (d+3 < p->buf+p->buf_size)
  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, AVFormatParameters *ap)
  57 {
  58     MPCContext *c = s->priv_data;
  59     AVStream *st;
  60     int t;
  61
  62     t = get_le24(s->pb);
  63     if(t != MKTAG('M', 'P', '+', 0)){
  64         if(t != MKTAG('I', 'D', '3', 0)){
  65             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  66             return -1;
  67         }
  68         /* skip ID3 tags and try again */
  69         url_fskip(s->pb, 3);
  70         t  = get_byte(s->pb) << 21;
  71         t |= get_byte(s->pb) << 14;
  72         t |= get_byte(s->pb) <<  7;
  73         t |= get_byte(s->pb);
  74         av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
  75         url_fskip(s->pb, t);
  76         if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
  77             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  78             return -1;
  79         }
  80     }
  81     c->ver = get_byte(s->pb);
  82     if(c->ver != 0x07 && c->ver != 0x17){
  83         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
  84         return -1;
  85     }
  86     c->fcount = get_le32(s->pb);
  87     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
  88         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
  89         return -1;
  90     }
  91     c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
  92     c->curframe = 0;
  93     c->lastframe = -1;
  94     c->curbits = 8;
  95     c->frames_noted = 0;
  96
  97     st = av_new_stream(s, 0);
  98     if (!st)
  99         return AVERROR(ENOMEM);
 100     st->codec->codec_type = CODEC_TYPE_AUDIO;
 101     st->codec->codec_id = CODEC_ID_MUSEPACK7;
 102     st->codec->channels = 2;
 103     st->codec->bits_per_coded_sample = 16;
 104
 105     st->codec->extradata_size = 16;
 106     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
 107     get_buffer(s->pb, st->codec->extradata, 16);
 108     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
 109     av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
 110     /* scan for seekpoints */
 111     s->start_time = 0;
 112     s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;
 113
 114     return 0;
 115 }
 116
 117 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 118 {
 119     MPCContext *c = s->priv_data;
 120     int ret, size, size2, curbits, cur = c->curframe;
 121     int64_t tmp, pos;
 122
 123     if (c->curframe >= c->fcount)
 124         return -1;
 125
 126     if(c->curframe != c->lastframe + 1){
 127         url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
 128         c->curbits = c->frames[c->curframe].skip;
 129     }
 130     c->lastframe = c->curframe;
 131     c->curframe++;
 132     curbits = c->curbits;
 133     pos = url_ftell(s->pb);
 134     tmp = get_le32(s->pb);
 135     if(curbits <= 12){
 136         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
 137     }else{
 138         tmp = (tmp << 32) | get_le32(s->pb);
 139         size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
 140     }
 141     curbits += 20;
 142     url_fseek(s->pb, pos, SEEK_SET);
 143
 144     size = ((size2 + curbits + 31) & ~31) >> 3;
 145     if(cur == c->frames_noted){
 146         c->frames[cur].pos = pos;
 147         c->frames[cur].size = size;
 148         c->frames[cur].skip = curbits - 20;
 149         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
 150         c->frames_noted++;
 151     }
 152     c->curbits = (curbits + size2) & 0x1F;
 153
 154     if (av_new_packet(pkt, size) < 0)
 155         return AVERROR(EIO);
 156
 157     pkt->data[0] = curbits;
 158     pkt->data[1] = (c->curframe > c->fcount);
 159
 160     pkt->stream_index = 0;
 161     pkt->pts = cur;
 162     ret = get_buffer(s->pb, pkt->data + 4, size);
 163     if(c->curbits)
 164         url_fseek(s->pb, -4, SEEK_CUR);
 165     if(ret < size){
 166         av_free_packet(pkt);
 167         return AVERROR(EIO);
 168     }
 169     pkt->size = ret + 4;
 170
 171     return 0;
 172 }
 173
 174 static int mpc_read_close(AVFormatContext *s)
 175 {
 176     MPCContext *c = s->priv_data;
 177
 178     av_freep(&c->frames);
 179     return 0;
 180 }
 181
 182 /**
 183  * Seek to the given position
 184  * If position is unknown but is within the limits of file
 185  * then packets are skipped unless desired position is reached
 186  *
 187  * Also this function makes use of the fact that timestamp == frameno
 188  */
 189 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 190 {
 191     AVStream *st = s->streams[stream_index];
 192     MPCContext *c = s->priv_data;
 193     AVPacket pkt1, *pkt = &pkt1;
 194     int ret;
 195     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
 196     uint32_t lastframe;
 197
 198     /* if found, seek there */
 199     if (index >= 0){
 200         c->curframe = st->index_entries[index].pos;
 201         return 0;
 202     }
 203     /* if timestamp is out of bounds, return error */
 204     if(timestamp < 0 || timestamp >= c->fcount)
 205         return -1;
 206     timestamp -= DELAY_FRAMES;
 207     /* seek to the furthest known position and read packets until
 208        we reach desired position */
 209     lastframe = c->curframe;
 210     if(c->frames_noted) c->curframe = c->frames_noted - 1;
 211     while(c->curframe < timestamp){
 212         ret = av_read_frame(s, pkt);
 213         if (ret < 0){
 214             c->curframe = lastframe;
 215             return -1;
 216         }
 217         av_free_packet(pkt);
 218     }
 219     return 0;
 220 }
 221
 222
 223 AVInputFormat mpc_demuxer = {
 224     "mpc",
 225     NULL_IF_CONFIG_SMALL("Musepack"),
 226     sizeof(MPCContext),
 227     mpc_probe,
 228     mpc_read_header,
 229     mpc_read_packet,
 230     mpc_read_close,
 231     mpc_read_seek,
 232     .extensions = "mpc",
 233 };