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