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 #include "apetag.h"
  26
  27 #define MPC_FRAMESIZE  1152
  28 #define DELAY_FRAMES   32
  29
  30 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
  31 typedef struct {
  32     int64_t pos;
  33     int size, skip;
  34 }MPCFrame;
  35
  36 typedef struct {
  37     int ver;
  38     uint32_t curframe, lastframe;
  39     uint32_t fcount;
  40     MPCFrame *frames;
  41     int curbits;
  42     int frames_noted;
  43 } MPCContext;
  44
  45 static int mpc_probe(AVProbeData *p)
  46 {
  47     const uint8_t *d = p->buf;
  48     if (ff_id3v2_match(d)) {
  49         d += ff_id3v2_tag_len(d);
  50     }
  51     if (d+3 < p->buf+p->buf_size)
  52     if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
  53         return AVPROBE_SCORE_MAX;
  54     return 0;
  55 }
  56
  57 static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
  58 {
  59     MPCContext *c = s->priv_data;
  60     AVStream *st;
  61     int t, ret;
  62     int64_t pos = url_ftell(s->pb);
  63
  64     t = get_le24(s->pb);
  65     if(t != MKTAG('M', 'P', '+', 0)){
  66         uint8_t buf[ID3v2_HEADER_SIZE];
  67         if (url_fseek(s->pb, pos, SEEK_SET) < 0)
  68             return -1;
  69         ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
  70         if (ret != ID3v2_HEADER_SIZE || !ff_id3v2_match(buf)) {
  71             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  72             return -1;
  73         }
  74         /* skip ID3 tags and try again */
  75         t = ff_id3v2_tag_len(buf) - ID3v2_HEADER_SIZE;
  76         av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
  77         url_fskip(s->pb, t);
  78         if(get_le24(s->pb) != MKTAG('M', 'P', '+', 0)){
  79             av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
  80             return -1;
  81         }
  82         /* read ID3 tags */
  83         if (url_fseek(s->pb, pos, SEEK_SET) < 0)
  84             return -1;
  85         ff_id3v2_read(s);
  86         get_le24(s->pb);
  87     }
  88     c->ver = get_byte(s->pb);
  89     if(c->ver != 0x07 && c->ver != 0x17){
  90         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
  91         return -1;
  92     }
  93     c->fcount = get_le32(s->pb);
  94     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
  95         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
  96         return -1;
  97     }
  98     c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
  99     c->curframe = 0;
 100     c->lastframe = -1;
 101     c->curbits = 8;
 102     c->frames_noted = 0;
 103
 104     st = av_new_stream(s, 0);
 105     if (!st)
 106         return AVERROR(ENOMEM);
 107     st->codec->codec_type = CODEC_TYPE_AUDIO;
 108     st->codec->codec_id = CODEC_ID_MUSEPACK7;
 109     st->codec->channels = 2;
 110     st->codec->bits_per_coded_sample = 16;
 111
 112     st->codec->extradata_size = 16;
 113     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
 114     get_buffer(s->pb, st->codec->extradata, 16);
 115     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
 116     av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
 117     /* scan for seekpoints */
 118     s->start_time = 0;
 119     s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;
 120
 121     /* try to read APE tags */
 122     if (!url_is_streamed(s->pb)) {
 123         int64_t pos = url_ftell(s->pb);
 124         ff_ape_parse_tag(s);
 125         url_fseek(s->pb, pos, SEEK_SET);
 126     }
 127
 128     return 0;
 129 }
 130
 131 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
 132 {
 133     MPCContext *c = s->priv_data;
 134     int ret, size, size2, curbits, cur = c->curframe;
 135     int64_t tmp, pos;
 136
 137     if (c->curframe >= c->fcount)
 138         return -1;
 139
 140     if(c->curframe != c->lastframe + 1){
 141         url_fseek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
 142         c->curbits = c->frames[c->curframe].skip;
 143     }
 144     c->lastframe = c->curframe;
 145     c->curframe++;
 146     curbits = c->curbits;
 147     pos = url_ftell(s->pb);
 148     tmp = get_le32(s->pb);
 149     if(curbits <= 12){
 150         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
 151     }else{
 152         tmp = (tmp << 32) | get_le32(s->pb);
 153         size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
 154     }
 155     curbits += 20;
 156     url_fseek(s->pb, pos, SEEK_SET);
 157
 158     size = ((size2 + curbits + 31) & ~31) >> 3;
 159     if(cur == c->frames_noted){
 160         c->frames[cur].pos = pos;
 161         c->frames[cur].size = size;
 162         c->frames[cur].skip = curbits - 20;
 163         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
 164         c->frames_noted++;
 165     }
 166     c->curbits = (curbits + size2) & 0x1F;
 167
 168     if (av_new_packet(pkt, size) < 0)
 169         return AVERROR(EIO);
 170
 171     pkt->data[0] = curbits;
 172     pkt->data[1] = (c->curframe > c->fcount);
 173
 174     pkt->stream_index = 0;
 175     pkt->pts = cur;
 176     ret = get_buffer(s->pb, pkt->data + 4, size);
 177     if(c->curbits)
 178         url_fseek(s->pb, -4, SEEK_CUR);
 179     if(ret < size){
 180         av_free_packet(pkt);
 181         return AVERROR(EIO);
 182     }
 183     pkt->size = ret + 4;
 184
 185     return 0;
 186 }
 187
 188 static int mpc_read_close(AVFormatContext *s)
 189 {
 190     MPCContext *c = s->priv_data;
 191
 192     av_freep(&c->frames);
 193     return 0;
 194 }
 195
 196 /**
 197  * Seek to the given position
 198  * If position is unknown but is within the limits of file
 199  * then packets are skipped unless desired position is reached
 200  *
 201  * Also this function makes use of the fact that timestamp == frameno
 202  */
 203 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 204 {
 205     AVStream *st = s->streams[stream_index];
 206     MPCContext *c = s->priv_data;
 207     AVPacket pkt1, *pkt = &pkt1;
 208     int ret;
 209     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
 210     uint32_t lastframe;
 211
 212     /* if found, seek there */
 213     if (index >= 0){
 214         c->curframe = st->index_entries[index].pos;
 215         return 0;
 216     }
 217     /* if timestamp is out of bounds, return error */
 218     if(timestamp < 0 || timestamp >= c->fcount)
 219         return -1;
 220     timestamp -= DELAY_FRAMES;
 221     /* seek to the furthest known position and read packets until
 222        we reach desired position */
 223     lastframe = c->curframe;
 224     if(c->frames_noted) c->curframe = c->frames_noted - 1;
 225     while(c->curframe < timestamp){
 226         ret = av_read_frame(s, pkt);
 227         if (ret < 0){
 228             c->curframe = lastframe;
 229             return -1;
 230         }
 231         av_free_packet(pkt);
 232     }
 233     return 0;
 234 }
 235
 236
 237 AVInputFormat mpc_demuxer = {
 238     "mpc",
 239     NULL_IF_CONFIG_SMALL("Musepack"),
 240     sizeof(MPCContext),
 241     mpc_probe,
 242     mpc_read_header,
 243     mpc_read_packet,
 244     mpc_read_close,
 245     mpc_read_seek,
 246     .extensions = "mpc",
 247 };