FFmpeg: libavformat/mpc.c Source File

00001 /*
00002  * Musepack demuxer
00003  * Copyright (c) 2006 Konstantin Shishkov
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavcodec/get_bits.h"
00023 #include "avformat.h"
00024 #include "internal.h"
00025 #include "apetag.h"
00026 #include "id3v1.h"
00027 #include "libavutil/dict.h"
00028 
00029 #define MPC_FRAMESIZE  1152
00030 #define DELAY_FRAMES   32
00031 
00032 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
00033 typedef struct {
00034     int64_t pos;
00035     int size, skip;
00036 }MPCFrame;
00037 
00038 typedef struct {
00039     int ver;
00040     uint32_t curframe, lastframe;
00041     uint32_t fcount;
00042     MPCFrame *frames;
00043     int curbits;
00044     int frames_noted;
00045 } MPCContext;
00046 
00047 static int mpc_probe(AVProbeData *p)
00048 {
00049     const uint8_t *d = p->buf;
00050     if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
00051         return AVPROBE_SCORE_MAX;
00052     return 0;
00053 }
00054 
00055 static int mpc_read_header(AVFormatContext *s)
00056 {
00057     MPCContext *c = s->priv_data;
00058     AVStream *st;
00059 
00060     if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
00061         av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
00062         return -1;
00063     }
00064     c->ver = avio_r8(s->pb);
00065     if(c->ver != 0x07 && c->ver != 0x17){
00066         av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
00067         return -1;
00068     }
00069     c->fcount = avio_rl32(s->pb);
00070     if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
00071         av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
00072         return -1;
00073     }
00074     if(c->fcount){
00075         c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
00076         if(!c->frames){
00077             av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
00078             return AVERROR(ENOMEM);
00079         }
00080     }else{
00081         av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
00082     }
00083     c->curframe = 0;
00084     c->lastframe = -1;
00085     c->curbits = 8;
00086     c->frames_noted = 0;
00087 
00088     st = avformat_new_stream(s, NULL);
00089     if (!st)
00090         return AVERROR(ENOMEM);
00091     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00092     st->codec->codec_id = CODEC_ID_MUSEPACK7;
00093     st->codec->channels = 2;
00094     st->codec->bits_per_coded_sample = 16;
00095 
00096     st->codec->extradata_size = 16;
00097     st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
00098     avio_read(s->pb, st->codec->extradata, 16);
00099     st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
00100     avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
00101     /* scan for seekpoints */
00102     st->start_time = 0;
00103     st->duration = c->fcount;
00104 
00105     /* try to read APE tags */
00106     if (s->pb->seekable) {
00107         int64_t pos = avio_tell(s->pb);
00108         ff_ape_parse_tag(s);
00109         if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
00110             ff_id3v1_read(s);
00111         avio_seek(s->pb, pos, SEEK_SET);
00112     }
00113 
00114     return 0;
00115 }
00116 
00117 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
00118 {
00119     MPCContext *c = s->priv_data;
00120     int ret, size, size2, curbits, cur = c->curframe;
00121     unsigned tmp;
00122     int64_t pos;
00123 
00124     if (c->curframe >= c->fcount && c->fcount)
00125         return -1;
00126 
00127     if(c->curframe != c->lastframe + 1){
00128         avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
00129         c->curbits = c->frames[c->curframe].skip;
00130     }
00131     c->lastframe = c->curframe;
00132     c->curframe++;
00133     curbits = c->curbits;
00134     pos = avio_tell(s->pb);
00135     tmp = avio_rl32(s->pb);
00136     if(curbits <= 12){
00137         size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
00138     }else{
00139         size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
00140     }
00141     curbits += 20;
00142     avio_seek(s->pb, pos, SEEK_SET);
00143 
00144     size = ((size2 + curbits + 31) & ~31) >> 3;
00145     if(cur == c->frames_noted && c->fcount){
00146         c->frames[cur].pos = pos;
00147         c->frames[cur].size = size;
00148         c->frames[cur].skip = curbits - 20;
00149         av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
00150         c->frames_noted++;
00151     }
00152     c->curbits = (curbits + size2) & 0x1F;
00153 
00154     if (av_new_packet(pkt, size) < 0)
00155         return AVERROR(EIO);
00156 
00157     pkt->data[0] = curbits;
00158     pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
00159     pkt->data[2] = 0;
00160     pkt->data[3] = 0;
00161 
00162     pkt->stream_index = 0;
00163     pkt->pts = cur;
00164     ret = avio_read(s->pb, pkt->data + 4, size);
00165     if(c->curbits)
00166         avio_seek(s->pb, -4, SEEK_CUR);
00167     if(ret < size){
00168         av_free_packet(pkt);
00169         return AVERROR(EIO);
00170     }
00171     pkt->size = ret + 4;
00172 
00173     return 0;
00174 }
00175 
00176 static int mpc_read_close(AVFormatContext *s)
00177 {
00178     MPCContext *c = s->priv_data;
00179 
00180     av_freep(&c->frames);
00181     return 0;
00182 }
00183 
00191 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
00192 {
00193     AVStream *st = s->streams[stream_index];
00194     MPCContext *c = s->priv_data;
00195     AVPacket pkt1, *pkt = &pkt1;
00196     int ret;
00197     int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
00198     uint32_t lastframe;
00199 
00200     /* if found, seek there */
00201     if (index >= 0){
00202         c->curframe = st->index_entries[index].pos;
00203         return 0;
00204     }
00205     /* if timestamp is out of bounds, return error */
00206     if(timestamp < 0 || timestamp >= c->fcount)
00207         return -1;
00208     timestamp -= DELAY_FRAMES;
00209     /* seek to the furthest known position and read packets until
00210        we reach desired position */
00211     lastframe = c->curframe;
00212     if(c->frames_noted) c->curframe = c->frames_noted - 1;
00213     while(c->curframe < timestamp){
00214         ret = av_read_frame(s, pkt);
00215         if (ret < 0){
00216             c->curframe = lastframe;
00217             return -1;
00218         }
00219         av_free_packet(pkt);
00220     }
00221     return 0;
00222 }
00223 
00224 
00225 AVInputFormat ff_mpc_demuxer = {
00226     .name           = "mpc",
00227     .long_name      = NULL_IF_CONFIG_SMALL("Musepack"),
00228     .priv_data_size = sizeof(MPCContext),
00229     .read_probe     = mpc_probe,
00230     .read_header    = mpc_read_header,
00231     .read_packet    = mpc_read_packet,
00232     .read_close     = mpc_read_close,
00233     .read_seek      = mpc_read_seek,
00234     .extensions     = "mpc",
00235 };