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ffmpeg / libavformat / mm.c @ 6a5d31ac

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/*
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 * American Laser Games MM Format Demuxer
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 * Copyright (c) 2006 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 mm.c
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 * American Laser Games MM Format Demuxer
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 * by Peter Ross (suxen_drol at hotmail dot com)
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 *
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 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
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 * including Mad Dog McCree and Crime Patrol.
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 *
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 * Technical details here:
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 *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
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 */
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#define MM_PREAMBLE_SIZE    6
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#define MM_TYPE_HEADER      0x0
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#define MM_TYPE_INTER       0x5
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#define MM_TYPE_INTRA       0x8
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#define MM_TYPE_INTRA_HH    0xc
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#define MM_TYPE_INTER_HH    0xd
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#define MM_TYPE_INTRA_HHV   0xe
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#define MM_TYPE_INTER_HHV   0xf
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#define MM_TYPE_AUDIO       0x15
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#define MM_TYPE_PALETTE     0x31
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#define MM_HEADER_LEN_V     0x16    /* video only */
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#define MM_HEADER_LEN_AV    0x18    /* video + audio */
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#define MM_PALETTE_COUNT    128
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#define MM_PALETTE_SIZE     (MM_PALETTE_COUNT*3)
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typedef struct {
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  unsigned int audio_pts, video_pts;
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} MmDemuxContext;
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static int mm_probe(AVProbeData *p)
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{
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    /* the first chunk is always the header */
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    if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER)
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        return 0;
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    if (AV_RL32(&p->buf[2]) != MM_HEADER_LEN_V && AV_RL32(&p->buf[2]) != MM_HEADER_LEN_AV)
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        return 0;
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    /* only return half certainty since this check is a bit sketchy */
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    return AVPROBE_SCORE_MAX / 2;
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}
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static int mm_read_header(AVFormatContext *s,
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                           AVFormatParameters *ap)
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{
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    MmDemuxContext *mm = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    AVStream *st;
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    unsigned int type, length;
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    unsigned int frame_rate, width, height;
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    type = get_le16(pb);
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    length = get_le32(pb);
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    if (type != MM_TYPE_HEADER)
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        return AVERROR_INVALIDDATA;
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    /* read header */
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    get_le16(pb);   /* total number of chunks */
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    frame_rate = get_le16(pb);
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    get_le16(pb);   /* ibm-pc video bios mode */
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    width = get_le16(pb);
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    height = get_le16(pb);
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    url_fseek(pb, length - 10, SEEK_CUR);  /* unknown data */
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    /* video stream */
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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 = CODEC_TYPE_VIDEO;
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    st->codec->codec_id = CODEC_ID_MMVIDEO;
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    st->codec->codec_tag = 0;  /* no fourcc */
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    st->codec->width = width;
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    st->codec->height = height;
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    av_set_pts_info(st, 64, 1, frame_rate);
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    /* audio stream */
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    if (length == MM_HEADER_LEN_AV) {
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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 = CODEC_TYPE_AUDIO;
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        st->codec->codec_tag = 0; /* no fourcc */
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        st->codec->codec_id = CODEC_ID_PCM_U8;
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        st->codec->channels = 1;
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        st->codec->sample_rate = 8000;
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        av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */
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    }
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    mm->audio_pts = 0;
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    mm->video_pts = 0;
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    return 0;
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}
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static int mm_read_packet(AVFormatContext *s,
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                           AVPacket *pkt)
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{
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    MmDemuxContext *mm = s->priv_data;
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    ByteIOContext *pb = s->pb;
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    unsigned char preamble[MM_PREAMBLE_SIZE];
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    unsigned int type, length;
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    while(1) {
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        if (get_buffer(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) {
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            return AVERROR(EIO);
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        }
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        type = AV_RL16(&preamble[0]);
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        length = AV_RL16(&preamble[2]);
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        switch(type) {
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        case MM_TYPE_PALETTE :
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        case MM_TYPE_INTER :
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        case MM_TYPE_INTRA :
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        case MM_TYPE_INTRA_HH :
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        case MM_TYPE_INTER_HH :
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        case MM_TYPE_INTRA_HHV :
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        case MM_TYPE_INTER_HHV :
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            /* output preamble + data */
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            if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE))
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                return AVERROR(ENOMEM);
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            memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE);
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            if (get_buffer(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length)
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                return AVERROR(EIO);
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            pkt->size = length + MM_PREAMBLE_SIZE;
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            pkt->stream_index = 0;
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            pkt->pts = mm->video_pts;
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            if (type!=MM_TYPE_PALETTE)
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                mm->video_pts++;
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            return 0;
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        case MM_TYPE_AUDIO :
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            if (av_get_packet(s->pb, pkt, length)<0)
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                return AVERROR(ENOMEM);
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            pkt->size = length;
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            pkt->stream_index = 1;
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            pkt->pts = mm->audio_pts++;
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            return 0;
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        default :
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            av_log(NULL, AV_LOG_INFO, "mm: unknown chunk type 0x%x\n", type);
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            url_fseek(pb, length, SEEK_CUR);
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        }
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    }
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    return 0;
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}
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AVInputFormat mm_demuxer = {
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    "mm",
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    NULL_IF_CONFIG_SMALL("American Laser Games MM format"),
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    sizeof(MmDemuxContext),
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    mm_probe,
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    mm_read_header,
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    mm_read_packet,
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};