PeerStreamer

/*

 * DXA demuxer

 * Copyright (c) 2007 Konstantin Shishkov

 *

 * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#include "riff.h"

#define DXA_EXTRA_SIZE  9

typedef struct{

    int frames;

    int has_sound;

    int bpc;

    uint32_t bytes_left;

    int64_t wavpos, vidpos;

    int readvid;

}DXAContext;

static int dxa_probe(AVProbeData *p)

{

    int w, h;

    if (p->buf_size < 15)

        return 0;

    w = AV_RB16(p->buf + 11);

    h = AV_RB16(p->buf + 13);

    /* check file header */

    if (p->buf[0] == 'D' && p->buf[1] == 'E' &&

        p->buf[2] == 'X' && p->buf[3] == 'A' &&

        w && w <= 2048 && h && h <= 2048)

        return AVPROBE_SCORE_MAX;

    else

        return 0;

}

static int dxa_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    AVIOContext *pb = s->pb;

    DXAContext *c = s->priv_data;

    AVStream *st, *ast;

    uint32_t tag;

    int32_t fps;

    int w, h;

    int num, den;

    int flags;

    tag = avio_rl32(pb);

    if (tag != MKTAG('D', 'E', 'X', 'A'))

        return -1;

    flags = avio_r8(pb);

    c->frames = avio_rb16(pb);

    if(!c->frames){

        av_log(s, AV_LOG_ERROR, "File contains no frames ???\n");

        return -1;

    }

    fps = avio_rb32(pb);

    if(fps > 0){

        den = 1000;

        num = fps;

    }else if (fps < 0){

        den = 100000;

        num = -fps;

    }else{

        den = 10;

        num = 1;

    }

    w = avio_rb16(pb);

    h = avio_rb16(pb);

    c->has_sound = 0;

    st = av_new_stream(s, 0);

    if (!st)

        return -1;

    // Parse WAV data header

    if(avio_rl32(pb) == MKTAG('W', 'A', 'V', 'E')){

        uint32_t size, fsize;

        c->has_sound = 1;

        size = avio_rb32(pb);

        c->vidpos = avio_tell(pb) + size;

        avio_seek(pb, 16, SEEK_CUR);

        fsize = avio_rl32(pb);

        ast = av_new_stream(s, 0);

        if (!ast)

            return -1;

        ff_get_wav_header(pb, ast->codec, fsize);

        // find 'data' chunk

        while(avio_tell(pb) < c->vidpos && !pb->eof_reached){

            tag = avio_rl32(pb);

            fsize = avio_rl32(pb);

            if(tag == MKTAG('d', 'a', 't', 'a')) break;

            avio_seek(pb, fsize, SEEK_CUR);

        }

        c->bpc = (fsize + c->frames - 1) / c->frames;

        if(ast->codec->block_align)

            c->bpc = ((c->bpc + ast->codec->block_align - 1) / ast->codec->block_align) * ast->codec->block_align;

        c->bytes_left = fsize;

        c->wavpos = avio_tell(pb);

        avio_seek(pb, c->vidpos, SEEK_SET);

    }

    /* now we are ready: build format streams */

    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

    st->codec->codec_id   = CODEC_ID_DXA;

    st->codec->width      = w;

    st->codec->height     = h;

    av_reduce(&den, &num, den, num, (1UL<<31)-1);

    av_set_pts_info(st, 33, num, den);

    /* flags & 0x80 means that image is interlaced,

     * flags & 0x40 means that image has double height

     * either way set true height

     */

    if(flags & 0xC0){

        st->codec->height >>= 1;

    }

    c->readvid = !c->has_sound;

    c->vidpos  = avio_tell(pb);

    s->start_time = 0;

    s->duration = (int64_t)c->frames * AV_TIME_BASE * num / den;

    av_log(s, AV_LOG_DEBUG, "%d frame(s)\n",c->frames);

    return 0;

}

static int dxa_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    DXAContext *c = s->priv_data;

    int ret;

    uint32_t size;

    uint8_t buf[DXA_EXTRA_SIZE], pal[768+4];

    int pal_size = 0;

    if(!c->readvid && c->has_sound && c->bytes_left){

        c->readvid = 1;

        avio_seek(s->pb, c->wavpos, SEEK_SET);

        size = FFMIN(c->bytes_left, c->bpc);

        ret = av_get_packet(s->pb, pkt, size);

        pkt->stream_index = 1;

        if(ret != size)

            return AVERROR(EIO);

        c->bytes_left -= size;

        c->wavpos = avio_tell(s->pb);

        return 0;

    }

    avio_seek(s->pb, c->vidpos, SEEK_SET);

    while(!s->pb->eof_reached && c->frames){

        avio_read(s->pb, buf, 4);

        switch(AV_RL32(buf)){

        case MKTAG('N', 'U', 'L', 'L'):

            if(av_new_packet(pkt, 4 + pal_size) < 0)

                return AVERROR(ENOMEM);

            pkt->stream_index = 0;

            if(pal_size) memcpy(pkt->data, pal, pal_size);

            memcpy(pkt->data + pal_size, buf, 4);

            c->frames--;

            c->vidpos = avio_tell(s->pb);

            c->readvid = 0;

            return 0;

        case MKTAG('C', 'M', 'A', 'P'):

            pal_size = 768+4;

            memcpy(pal, buf, 4);

            avio_read(s->pb, pal + 4, 768);

            break;

        case MKTAG('F', 'R', 'A', 'M'):

            avio_read(s->pb, buf + 4, DXA_EXTRA_SIZE - 4);

            size = AV_RB32(buf + 5);

            if(size > 0xFFFFFF){

                av_log(s, AV_LOG_ERROR, "Frame size is too big: %d\n", size);

                return -1;

            }

            if(av_new_packet(pkt, size + DXA_EXTRA_SIZE + pal_size) < 0)

                return AVERROR(ENOMEM);

            memcpy(pkt->data + pal_size, buf, DXA_EXTRA_SIZE);

            ret = avio_read(s->pb, pkt->data + DXA_EXTRA_SIZE + pal_size, size);

            if(ret != size){

                av_free_packet(pkt);

                return AVERROR(EIO);

            }

            if(pal_size) memcpy(pkt->data, pal, pal_size);

            pkt->stream_index = 0;

            c->frames--;

            c->vidpos = avio_tell(s->pb);

            c->readvid = 0;

            return 0;

        default:

            av_log(s, AV_LOG_ERROR, "Unknown tag %c%c%c%c\n", buf[0], buf[1], buf[2], buf[3]);

            return -1;

        }

    }

    return AVERROR(EIO);

}

AVInputFormat ff_dxa_demuxer = {

    "dxa",

    NULL_IF_CONFIG_SMALL("DXA"),

    sizeof(DXAContext),

    dxa_probe,

    dxa_read_header,

    dxa_read_packet,

};