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/bitstream.h"
  23 #include "avformat.h"
  24
  25 #define MPC_FRAMESIZE  1152
  26 #define DELAY_FRAMES   32
  27
  28 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
  29 typedef struct {
  30     int64_t pos;
  31     int size, skip;
  32 }MPCFrame;
  33
  34 typedef struct {
  35     int ver;
  36     uint32_t curframe, lastframe;
  37     uint32_t fcount;
  38     MPCFrame *frames;
  39     int curbits;
  40     int frames_noted;
  41 } MPCContext;
  42
  43 static int mpc_probe(AVProbeData *p)
  44 {
  45     const uint8_t *d = p->buf;
  46     if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
  47         return AVPROBE_SCORE_MAX;
  48     if (d[0] == 'I' && d[1] == 'D' && d[2] == '3')
  49         return AVPROBE_SCORE_MAX / 2;
  50     return 0;
  51 }
  52
  53 static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
  54 {
  55     MPCContext *c = s->priv_data;
  56     AVStream *st;
  57     int t;
  58
  59     t = get_le24(s->pb);
  60     if(t != MKTAG('M', 'P', '+', 0)){
  61         if(t != MKTAG('I', 'D', '3', 0)){
  62             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  63             return -1;
  64         }
  65         /* skip ID3 tags and try again */
  66         url_fskip(s->pb, 3);
  67         t  = get_byte(s->pb) << 21;
  68         t |= get_byte(s->pb) << 14;
  69         t |= get_byte(s->pb) <<  7;
  70         t |= get_byte(s->pb);
  71         av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
  72         url_fskip(s->pb, t);
  73         if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
  74             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  75             return -1;
  76         }
  77     }
  78     c->ver = get_byte(s->pb);
  79     if(c->ver != 0x07 && c->ver != 0x17){
  80         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
  81         return -1;
  82     }
  83     c->fcount = get_le32(s->pb);
  84     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
  85         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
  86         return -1;
  87     }
  88     c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
  89     c->curframe = 0;
  90     c->lastframe = -1;
  91     c->curbits = 8;
  92     c->frames_noted = 0;
  93
  94     st = av_new_stream(s, 0);
  95     if (!st)
  96         return AVERROR(ENOMEM);
  97     st->codec->codec_type = CODEC_TYPE_AUDIO;
  98     st->codec->codec_id = CODEC_ID_MUSEPACK7;
  99     st->codec->channels = 2;
 100     st->codec->bits_per_sample = 16;
 101
 102     st->codec->extradata_size = 16;
 103     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
 104     get_buffer(s->pb, st->codec->extradata, 16);
 105     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
 106     av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
 107     /* scan for seekpoints */
 108     s->start_time = 0;
 109     s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;
 110
 111     return 0;
 112 }
 113
 114 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 115 {
 116     MPCContext *c = s->priv_data;
 117     int ret, size, size2, curbits, cur = c->curframe;
 118     int64_t tmp, pos;
 119
 120     if (c->curframe >= c->fcount)
 121         return -1;
 122
 123     if(c->curframe != c->lastframe + 1){
 124         url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
 125         c->curbits = c->frames[c->curframe].skip;
 126     }
 127     c->lastframe = c->curframe;
 128     c->curframe++;
 129     curbits = c->curbits;
 130     pos = url_ftell(s->pb);
 131     tmp = get_le32(s->pb);
 132     if(curbits <= 12){
 133         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
 134     }else{
 135         tmp = (tmp << 32) | get_le32(s->pb);
 136         size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
 137     }
 138     curbits += 20;
 139     url_fseek(s->pb, pos, SEEK_SET);
 140
 141     size = ((size2 + curbits + 31) & ~31) >> 3;
 142     if(cur == c->frames_noted){
 143         c->frames[cur].pos = pos;
 144         c->frames[cur].size = size;
 145         c->frames[cur].skip = curbits - 20;
 146         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
 147         c->frames_noted++;
 148     }
 149     c->curbits = (curbits + size2) & 0x1F;
 150
 151     if (av_new_packet(pkt, size) < 0)
 152         return AVERROR(EIO);
 153
 154     pkt->data[0] = curbits;
 155     pkt->data[1] = (c->curframe > c->fcount);
 156
 157     pkt->stream_index = 0;
 158     pkt->pts = cur;
 159     ret = get_buffer(s->pb, pkt->data + 4, size);
 160     if(c->curbits)
 161         url_fseek(s->pb, -4, SEEK_CUR);
 162     if(ret < size){
 163         av_free_packet(pkt);
 164         return AVERROR(EIO);
 165     }
 166     pkt->size = ret + 4;
 167
 168     return 0;
 169 }
 170
 171 static int mpc_read_close(AVFormatContext *s)
 172 {
 173     MPCContext *c = s->priv_data;
 174
 175     av_freep(&c->frames);
 176     return 0;
 177 }
 178
 179 /**
 180  * Seek to the given position
 181  * If position is unknown but is within the limits of file
 182  * then packets are skipped unless desired position is reached
 183  *
 184  * Also this function makes use of the fact that timestamp == frameno
 185  */
 186 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 187 {
 188     AVStream *st = s->streams[stream_index];
 189     MPCContext *c = s->priv_data;
 190     AVPacket pkt1, *pkt = &pkt1;
 191     int ret;
 192     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
 193     uint32_t lastframe;
 194
 195     /* if found, seek there */
 196     if (index >= 0){
 197         c->curframe = st->index_entries[index].pos;
 198         return 0;
 199     }
 200     /* if timestamp is out of bounds, return error */
 201     if(timestamp < 0 || timestamp >= c->fcount)
 202         return -1;
 203     timestamp -= DELAY_FRAMES;
 204     /* seek to the furthest known position and read packets until
 205        we reach desired position */
 206     lastframe = c->curframe;
 207     if(c->frames_noted) c->curframe = c->frames_noted - 1;
 208     while(c->curframe < timestamp){
 209         ret = av_read_frame(s, pkt);
 210         if (ret < 0){
 211             c->curframe = lastframe;
 212             return -1;
 213         }
 214         av_free_packet(pkt);
 215     }
 216     return 0;
 217 }
 218
 219
 220 AVInputFormat mpc_demuxer = {
 221     "mpc",
 222     NULL_IF_CONFIG_SMALL("Musepack"),
 223     sizeof(MPCContext),
 224     mpc_probe,
 225     mpc_read_header,
 226     mpc_read_packet,
 227     mpc_read_close,
 228     mpc_read_seek,
 229     .extensions = "mpc",
 230 };