mirror of https://git.ffmpeg.org/ffmpeg.git
238 lines
6.9 KiB
C
238 lines
6.9 KiB
C
/*
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* Musepack demuxer
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* Copyright (c) 2006 Konstantin Shishkov
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/channel_layout.h"
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#include "libavcodec/get_bits.h"
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#include "avformat.h"
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#include "internal.h"
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#include "apetag.h"
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#include "id3v1.h"
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#include "libavutil/dict.h"
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#define MPC_FRAMESIZE 1152
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#define DELAY_FRAMES 32
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static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
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typedef struct MPCFrame {
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int64_t pos;
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int size, skip;
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}MPCFrame;
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typedef struct MPCContext {
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int ver;
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uint32_t curframe, lastframe;
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uint32_t fcount;
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MPCFrame *frames;
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int curbits;
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int frames_noted;
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} MPCContext;
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static int mpc_probe(AVProbeData *p)
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{
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const uint8_t *d = p->buf;
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if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int mpc_read_header(AVFormatContext *s)
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{
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MPCContext *c = s->priv_data;
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AVStream *st;
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if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
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av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
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return AVERROR_INVALIDDATA;
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}
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c->ver = avio_r8(s->pb);
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if(c->ver != 0x07 && c->ver != 0x17){
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av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
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return AVERROR_INVALIDDATA;
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}
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c->fcount = avio_rl32(s->pb);
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if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
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av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
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return AVERROR_INVALIDDATA;
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}
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if(c->fcount){
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c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
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if(!c->frames){
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av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
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return AVERROR(ENOMEM);
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}
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}else{
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av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
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}
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c->curframe = 0;
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c->lastframe = -1;
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c->curbits = 8;
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c->frames_noted = 0;
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codec->codec_id = AV_CODEC_ID_MUSEPACK7;
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st->codec->channels = 2;
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st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
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st->codec->bits_per_coded_sample = 16;
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st->codec->extradata_size = 16;
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st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
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avio_read(s->pb, st->codec->extradata, 16);
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st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
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avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
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/* scan for seekpoints */
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st->start_time = 0;
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st->duration = c->fcount;
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/* try to read APE tags */
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if (s->pb->seekable) {
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int64_t pos = avio_tell(s->pb);
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ff_ape_parse_tag(s);
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if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
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ff_id3v1_read(s);
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avio_seek(s->pb, pos, SEEK_SET);
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}
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return 0;
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}
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static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MPCContext *c = s->priv_data;
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int ret, size, size2, curbits, cur = c->curframe;
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unsigned tmp;
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int64_t pos;
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if (c->curframe >= c->fcount && c->fcount)
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return AVERROR_EOF;
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if(c->curframe != c->lastframe + 1){
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avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
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c->curbits = c->frames[c->curframe].skip;
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}
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c->lastframe = c->curframe;
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c->curframe++;
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curbits = c->curbits;
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pos = avio_tell(s->pb);
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tmp = avio_rl32(s->pb);
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if(curbits <= 12){
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size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
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}else{
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size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
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}
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curbits += 20;
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avio_seek(s->pb, pos, SEEK_SET);
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size = ((size2 + curbits + 31) & ~31) >> 3;
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if(cur == c->frames_noted && c->fcount){
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c->frames[cur].pos = pos;
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c->frames[cur].size = size;
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c->frames[cur].skip = curbits - 20;
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av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
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c->frames_noted++;
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}
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c->curbits = (curbits + size2) & 0x1F;
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if ((ret = av_new_packet(pkt, size)) < 0)
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return ret;
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pkt->data[0] = curbits;
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pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
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pkt->data[2] = 0;
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pkt->data[3] = 0;
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pkt->stream_index = 0;
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pkt->pts = cur;
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ret = avio_read(s->pb, pkt->data + 4, size);
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if(c->curbits)
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avio_seek(s->pb, -4, SEEK_CUR);
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if(ret < size){
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av_free_packet(pkt);
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return ret < 0 ? ret : AVERROR(EIO);
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}
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pkt->size = ret + 4;
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return 0;
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}
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static int mpc_read_close(AVFormatContext *s)
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{
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MPCContext *c = s->priv_data;
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av_freep(&c->frames);
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return 0;
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}
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/**
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* Seek to the given position
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* If position is unknown but is within the limits of file
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* then packets are skipped unless desired position is reached
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*
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* Also this function makes use of the fact that timestamp == frameno
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*/
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static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
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{
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AVStream *st = s->streams[stream_index];
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MPCContext *c = s->priv_data;
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AVPacket pkt1, *pkt = &pkt1;
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int ret;
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int index = av_index_search_timestamp(st, timestamp - DELAY_FRAMES, flags);
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uint32_t lastframe;
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/* if found, seek there */
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if (index >= 0){
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c->curframe = st->index_entries[index].pos;
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return 0;
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}
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/* if timestamp is out of bounds, return error */
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if(timestamp < 0 || timestamp >= c->fcount)
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return -1;
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timestamp -= DELAY_FRAMES;
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/* seek to the furthest known position and read packets until
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we reach desired position */
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lastframe = c->curframe;
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if(c->frames_noted) c->curframe = c->frames_noted - 1;
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while(c->curframe < timestamp){
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ret = av_read_frame(s, pkt);
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if (ret < 0){
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c->curframe = lastframe;
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return ret;
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}
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av_free_packet(pkt);
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}
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return 0;
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}
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AVInputFormat ff_mpc_demuxer = {
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.name = "mpc",
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.long_name = NULL_IF_CONFIG_SMALL("Musepack"),
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.priv_data_size = sizeof(MPCContext),
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.read_probe = mpc_probe,
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.read_header = mpc_read_header,
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.read_packet = mpc_read_packet,
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.read_close = mpc_read_close,
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.read_seek = mpc_read_seek,
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.extensions = "mpc",
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};
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