PeerStreamer

/*

 * American Laser Games MM Format Demuxer

 * Copyright (c) 2006 Peter Ross

 *

 * This file is part of Libav.

 *

 * Libav is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * Libav is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * American Laser Games MM Format Demuxer

 * by Peter Ross (pross@xvid.org)

 *

 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,

 * including Mad Dog McCree and Crime Patrol.

 *

 * Technical details here:

 *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#define MM_PREAMBLE_SIZE    6

#define MM_TYPE_HEADER      0x0

#define MM_TYPE_INTER       0x5

#define MM_TYPE_INTRA       0x8

#define MM_TYPE_INTRA_HH    0xc

#define MM_TYPE_INTER_HH    0xd

#define MM_TYPE_INTRA_HHV   0xe

#define MM_TYPE_INTER_HHV   0xf

#define MM_TYPE_AUDIO       0x15

#define MM_TYPE_PALETTE     0x31

#define MM_HEADER_LEN_V     0x16    /* video only */

#define MM_HEADER_LEN_AV    0x18    /* video + audio */

#define MM_PALETTE_COUNT    128

#define MM_PALETTE_SIZE     (MM_PALETTE_COUNT*3)

typedef struct {

  unsigned int audio_pts, video_pts;

} MmDemuxContext;

static int probe(AVProbeData *p)

{

    int len, type, fps, w, h;

    if (p->buf_size < MM_HEADER_LEN_AV + MM_PREAMBLE_SIZE)

        return 0;

    /* the first chunk is always the header */

    if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER)

        return 0;

    len = AV_RL32(&p->buf[2]);

    if (len != MM_HEADER_LEN_V && len != MM_HEADER_LEN_AV)

        return 0;

    fps = AV_RL16(&p->buf[8]);

    w = AV_RL16(&p->buf[12]);

    h = AV_RL16(&p->buf[14]);

    if (!fps || fps > 60 || !w || w > 2048 || !h || h > 2048)

        return 0;

    type = AV_RL16(&p->buf[len]);

    if (!type || type > 0x31)

        return 0;

    /* only return half certainty since this check is a bit sketchy */

    return AVPROBE_SCORE_MAX / 2;

}

static int read_header(AVFormatContext *s,

                           AVFormatParameters *ap)

{

    MmDemuxContext *mm = s->priv_data;

    AVIOContext *pb = s->pb;

    AVStream *st;

    unsigned int type, length;

    unsigned int frame_rate, width, height;

    type = avio_rl16(pb);

    length = avio_rl32(pb);

    if (type != MM_TYPE_HEADER)

        return AVERROR_INVALIDDATA;

    /* read header */

    avio_rl16(pb);   /* total number of chunks */

    frame_rate = avio_rl16(pb);

    avio_rl16(pb);   /* ibm-pc video bios mode */

    width = avio_rl16(pb);

    height = avio_rl16(pb);

    avio_skip(pb, length - 10);  /* unknown data */

    /* video stream */

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR(ENOMEM);

    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

    st->codec->codec_id = CODEC_ID_MMVIDEO;

    st->codec->codec_tag = 0;  /* no fourcc */

    st->codec->width = width;

    st->codec->height = height;

    av_set_pts_info(st, 64, 1, frame_rate);

    /* audio stream */

    if (length == MM_HEADER_LEN_AV) {

        st = av_new_stream(s, 0);

        if (!st)

            return AVERROR(ENOMEM);

        st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codec->codec_tag = 0; /* no fourcc */

        st->codec->codec_id = CODEC_ID_PCM_U8;

        st->codec->channels = 1;

        st->codec->sample_rate = 8000;

        av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */

    }

    mm->audio_pts = 0;

    mm->video_pts = 0;

    return 0;

}

static int read_packet(AVFormatContext *s,

                           AVPacket *pkt)

{

    MmDemuxContext *mm = s->priv_data;

    AVIOContext *pb = s->pb;

    unsigned char preamble[MM_PREAMBLE_SIZE];

    unsigned int type, length;

    while(1) {

        if (avio_read(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) {

            return AVERROR(EIO);

        }

        type = AV_RL16(&preamble[0]);

        length = AV_RL16(&preamble[2]);

        switch(type) {

        case MM_TYPE_PALETTE :

        case MM_TYPE_INTER :

        case MM_TYPE_INTRA :

        case MM_TYPE_INTRA_HH :

        case MM_TYPE_INTER_HH :

        case MM_TYPE_INTRA_HHV :

        case MM_TYPE_INTER_HHV :

            /* output preamble + data */

            if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE))

                return AVERROR(ENOMEM);

            memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE);

            if (avio_read(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length)

                return AVERROR(EIO);

            pkt->size = length + MM_PREAMBLE_SIZE;

            pkt->stream_index = 0;

            pkt->pts = mm->video_pts;

            if (type!=MM_TYPE_PALETTE)

                mm->video_pts++;

            return 0;

        case MM_TYPE_AUDIO :

            if (av_get_packet(s->pb, pkt, length)<0)

                return AVERROR(ENOMEM);

            pkt->size = length;

            pkt->stream_index = 1;

            pkt->pts = mm->audio_pts++;

            return 0;

        default :

            av_log(s, AV_LOG_INFO, "unknown chunk type 0x%x\n", type);

            avio_skip(pb, length);

        }

    }

    return 0;

}

AVInputFormat ff_mm_demuxer = {

    "mm",

    NULL_IF_CONFIG_SMALL("American Laser Games MM format"),

    sizeof(MmDemuxContext),

    probe,

    read_header,

    read_packet,

};