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ffmpeg / libavformat / iss.c @ 72415b2a

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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 libavformat/iss.c
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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(ByteIOContext *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 = get_byte(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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        get_byte(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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    ByteIOContext *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 = url_ftell(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 = url_ftell(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 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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