ffmpeg / libavformat / iss.c @ a2704c97
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/*
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* ISS (.iss) file demuxer
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* Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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/**
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* @file
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* Funcom ISS file demuxer
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* @author Jaikrishnan Menon
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* for more information on the .iss file format, visit:
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* http://wiki.multimedia.cx/index.php?title=FunCom_ISS
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*/
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#include "avformat.h" |
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#include "libavutil/avstring.h" |
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#define ISS_SIG "IMA_ADPCM_Sound" |
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#define ISS_SIG_LEN 15 |
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#define MAX_TOKEN_SIZE 20 |
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typedef struct { |
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int packet_size;
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int sample_start_pos;
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} IssDemuxContext; |
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static void get_token(AVIOContext *s, char *buf, int maxlen) |
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{ |
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int i = 0; |
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char c;
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while ((c = avio_r8(s))) {
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if(c == ' ') |
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break;
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if (i < maxlen-1) |
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buf[i++] = c; |
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} |
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if(!c)
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avio_r8(s); |
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buf[i] = 0; /* Ensure null terminated, but may be truncated */ |
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} |
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static int iss_probe(AVProbeData *p) |
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{ |
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if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))
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return 0; |
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return AVPROBE_SCORE_MAX;
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} |
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static av_cold int iss_read_header(AVFormatContext *s, AVFormatParameters *ap) |
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{ |
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IssDemuxContext *iss = s->priv_data; |
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AVIOContext *pb = s->pb; |
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AVStream *st; |
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char token[MAX_TOKEN_SIZE];
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int stereo, rate_divisor;
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get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound" |
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get_token(pb, token, sizeof(token)); //packet size |
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sscanf(token, "%d", &iss->packet_size);
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get_token(pb, token, sizeof(token)); //File ID |
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get_token(pb, token, sizeof(token)); //out size |
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get_token(pb, token, sizeof(token)); //stereo |
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sscanf(token, "%d", &stereo);
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get_token(pb, token, sizeof(token)); //Unknown1 |
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get_token(pb, token, sizeof(token)); //RateDivisor |
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sscanf(token, "%d", &rate_divisor);
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get_token(pb, token, sizeof(token)); //Unknown2 |
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get_token(pb, token, sizeof(token)); //Version ID |
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get_token(pb, token, sizeof(token)); //Size |
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iss->sample_start_pos = avio_tell(pb); |
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st = av_new_stream(s, 0);
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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 = CODEC_ID_ADPCM_IMA_ISS; |
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st->codec->channels = stereo ? 2 : 1; |
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st->codec->sample_rate = 44100;
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if(rate_divisor > 0) |
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st->codec->sample_rate /= rate_divisor; |
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st->codec->bits_per_coded_sample = 4;
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st->codec->bit_rate = st->codec->channels * st->codec->sample_rate |
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* st->codec->bits_per_coded_sample; |
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st->codec->block_align = iss->packet_size; |
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av_set_pts_info(st, 32, 1, st->codec->sample_rate); |
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return 0; |
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} |
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static int iss_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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IssDemuxContext *iss = s->priv_data; |
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int ret = av_get_packet(s->pb, pkt, iss->packet_size);
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if(ret != iss->packet_size)
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return AVERROR(EIO);
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pkt->stream_index = 0;
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pkt->pts = avio_tell(s->pb) - iss->sample_start_pos; |
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if(s->streams[0]->codec->channels > 0) |
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pkt->pts /= s->streams[0]->codec->channels*2; |
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return 0; |
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} |
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AVInputFormat ff_iss_demuxer = { |
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"ISS",
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NULL_IF_CONFIG_SMALL("Funcom ISS format"),
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sizeof(IssDemuxContext),
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iss_probe, |
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iss_read_header, |
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iss_read_packet, |
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}; |
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