PeerStreamer

/*

 * American Laser Games MM Format Demuxer

 * Copyright (c) 2006 Peter Ross

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

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

 */

/**

 * @file mm.c

 * American Laser Games MM Format Demuxer

 * by Peter Ross (suxen_drol at hotmail dot com)

 *

 * 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 "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 {

  AVPaletteControl palette_control;

  unsigned int audio_pts, video_pts;

} MmDemuxContext;

static int mm_probe(AVProbeData *p)

{

    /* the first chunk is always the header */

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

        return 0;

    if (AV_RL32(&p->buf[2]) != MM_HEADER_LEN_V && AV_RL32(&p->buf[2]) != MM_HEADER_LEN_AV)

        return 0;

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

    return AVPROBE_SCORE_MAX / 2;

}

static int mm_read_header(AVFormatContext *s,

                           AVFormatParameters *ap)

{

    MmDemuxContext *mm = s->priv_data;

    ByteIOContext *pb = &s->pb;

    AVStream *st;

    unsigned int type, length;

    unsigned int frame_rate, width, height;

    type = get_le16(pb);

    length = get_le32(pb);

    if (type != MM_TYPE_HEADER)

        return AVERROR_INVALIDDATA;

    /* read header */

    get_le16(pb);   /* total number of chunks */

    frame_rate = get_le16(pb);

    get_le16(pb);   /* ibm-pc video bios mode */

    width = get_le16(pb);

    height = get_le16(pb);

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

    /* video stream */

    st = av_new_stream(s, 0);

    if (!st)

        return AVERROR_NOMEM;

    st->codec->codec_type = CODEC_TYPE_VIDEO;

    st->codec->codec_id = CODEC_ID_MMVIDEO;

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

    st->codec->width = width;

    st->codec->height = height;

    st->codec->palctrl = &mm->palette_control;

    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_NOMEM;

        st->codec->codec_type = CODEC_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->palette_control.palette_changed = 0;

    mm->audio_pts = 0;

    mm->video_pts = 0;

    return 0;

}

static int mm_read_packet(AVFormatContext *s,

                           AVPacket *pkt)

{

    MmDemuxContext *mm = s->priv_data;

    ByteIOContext *pb = &s->pb;

    unsigned char preamble[MM_PREAMBLE_SIZE];

    unsigned char pal[MM_PALETTE_SIZE];

    unsigned int type, length;

    int i;

    while(1) {

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

            return AVERROR_IO;

        }

        type = AV_RL16(&preamble[0]);

        length = AV_RL16(&preamble[2]);

        switch(type) {

        case MM_TYPE_PALETTE :

            url_fseek(pb, 4, SEEK_CUR);  /* unknown data */

            if (get_buffer(pb, pal, MM_PALETTE_SIZE) != MM_PALETTE_SIZE)

                return AVERROR_IO;

            url_fseek(pb, length - (4 + MM_PALETTE_SIZE), SEEK_CUR);

            for (i=0; i<MM_PALETTE_COUNT; i++) {

                int r = pal[i*3 + 0];

                int g = pal[i*3 + 1];

                int b = pal[i*3 + 2];

                mm->palette_control.palette[i] = (r << 16) | (g << 8) | (b);

                /* repeat palette, where each components is multiplied by four */

                mm->palette_control.palette[i+128] = (r << 18) | (g << 10) | (b<<2);

            }

            mm->palette_control.palette_changed = 1;

            break;

        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_NOMEM;

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

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

                return AVERROR_IO;

            pkt->size = length + MM_PREAMBLE_SIZE;

            pkt->stream_index = 0;

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

            return 0;

        case MM_TYPE_AUDIO :

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

                return AVERROR_NOMEM;

            pkt->size = length;

            pkt->stream_index = 1;

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

            return 0;

        default :

            av_log(NULL, AV_LOG_INFO, "mm: unknown chunk type 0x%x\n", type);

            url_fseek(pb, length, SEEK_CUR);

        }

    }

    return 0;

}

static int mm_read_close(AVFormatContext *s)

{

    return 0;

}

AVInputFormat mm_demuxer = {

    "mm",

    "American Laser Games MM format",

    sizeof(MmDemuxContext),

    mm_probe,

    mm_read_header,

    mm_read_packet,

    mm_read_close,

};