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ffmpeg / libavformat / eacdata.c @ b7effd4e

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/*
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 * Electronic Arts .cdata file Demuxer
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 * Copyright (c) 2007 Peter Ross
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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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 * Electronic Arts cdata Format Demuxer
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 * by Peter Ross (pross@xvid.org)
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 *
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 * Technical details here:
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 *  http://wiki.multimedia.cx/index.php?title=EA_Command_And_Conquer_3_Audio_Codec
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 */
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#include "avformat.h"
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typedef struct {
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  unsigned int channels;
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  unsigned int audio_pts;
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} CdataDemuxContext;
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static int cdata_probe(AVProbeData *p)
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{
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    const uint8_t *b = p->buf;
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    if (b[0] == 0x04 && (b[1] == 0x00 || b[1] == 0x04 || b[1] == 0x0C))
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        return AVPROBE_SCORE_MAX/8;
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    return 0;
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}
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static int cdata_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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    CdataDemuxContext *cdata = s->priv_data;
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    AVIOContext *pb = s->pb;
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    unsigned int sample_rate, header;
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    AVStream *st;
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    header = avio_rb16(pb);
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    switch (header) {
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        case 0x0400: cdata->channels = 1; break;
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        case 0x0404: cdata->channels = 2; break;
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        case 0x040C: cdata->channels = 4; break;
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        default:
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            av_log(s, AV_LOG_INFO, "unknown header 0x%04x\n", header);
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            return -1;
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    };
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    sample_rate = avio_rb16(pb);
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    url_fskip(pb, 12);
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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_tag = 0; /* no fourcc */
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    st->codec->codec_id = CODEC_ID_ADPCM_EA_XAS;
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    st->codec->channels = cdata->channels;
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    st->codec->sample_rate = sample_rate;
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    av_set_pts_info(st, 64, 1, sample_rate);
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    cdata->audio_pts = 0;
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    return 0;
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}
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static int cdata_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    CdataDemuxContext *cdata = s->priv_data;
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    int packet_size = 76*cdata->channels;
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    int ret = av_get_packet(s->pb, pkt, packet_size);
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    if (ret < 0)
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        return ret;
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    pkt->pts = cdata->audio_pts++;
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    return 0;
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}
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AVInputFormat ff_ea_cdata_demuxer = {
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    "ea_cdata",
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    NULL_IF_CONFIG_SMALL("Electronic Arts cdata"),
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    sizeof(CdataDemuxContext),
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    cdata_probe,
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    cdata_read_header,
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    cdata_read_packet,
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    .extensions = "cdata",
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};