PeerStreamer

/*

 * Bethsoft VID format Demuxer

 * Copyright (c) 2007 Nicholas Tung

 *

 * 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

 * @brief Bethesda Softworks VID (.vid) file demuxer

 * @author Nicholas Tung [ntung (at. ntung com] (2007-03)

 * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID

 * @sa http://www.svatopluk.com/andux/docs/dfvid.html

 */

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#include "libavcodec/bethsoftvideo.h"

typedef struct BVID_DemuxContext

{

    int nframes;

    /** delay value between frames, added to individual frame delay.

     * custom units, which will be added to other custom units (~=16ms according

     * to free, unofficial documentation) */

    int bethsoft_global_delay;

    /** video presentation time stamp.

     * delay = 16 milliseconds * (global_delay + per_frame_delay) */

    int video_pts;

    int is_finished;

} BVID_DemuxContext;

static int vid_probe(AVProbeData *p)

{

    // little endian VID tag, file starts with "VID\0"

    if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))

        return 0;

    return AVPROBE_SCORE_MAX;

}

static int vid_read_header(AVFormatContext *s,

                            AVFormatParameters *ap)

{

    BVID_DemuxContext *vid = s->priv_data;

    AVIOContext *pb = s->pb;

    AVStream *stream;

    /* load main header. Contents:

    *    bytes: 'V' 'I' 'D'

    *    int16s: always_512, nframes, width, height, delay, always_14

    */

    avio_skip(pb, 5);

    vid->nframes = avio_rl16(pb);

    stream = av_new_stream(s, 0);

    if (!stream)

        return AVERROR(ENOMEM);

    av_set_pts_info(stream, 32, 1, 60);     // 16 ms increments, i.e. 60 fps

    stream->codec->codec_type = AVMEDIA_TYPE_VIDEO;

    stream->codec->codec_id = CODEC_ID_BETHSOFTVID;

    stream->codec->width = avio_rl16(pb);

    stream->codec->height = avio_rl16(pb);

    stream->codec->pix_fmt = PIX_FMT_PAL8;

    vid->bethsoft_global_delay = avio_rl16(pb);

    avio_rl16(pb);

    // done with video codec, set up audio codec

    stream = av_new_stream(s, 0);

    if (!stream)

        return AVERROR(ENOMEM);

    stream->codec->codec_type = AVMEDIA_TYPE_AUDIO;

    stream->codec->codec_id = CODEC_ID_PCM_U8;

    stream->codec->channels = 1;

    stream->codec->sample_rate = 11025;

    stream->codec->bits_per_coded_sample = 8;

    stream->codec->bit_rate = stream->codec->channels * stream->codec->sample_rate * stream->codec->bits_per_coded_sample;

    return 0;

}

#define BUFFER_PADDING_SIZE 1000

static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,

                      uint8_t block_type, AVFormatContext *s, int npixels)

{

    uint8_t * vidbuf_start = NULL;

    int vidbuf_nbytes = 0;

    int code;

    int bytes_copied = 0;

    int position;

    unsigned int vidbuf_capacity;

    vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);

    if(!vidbuf_start)

        return AVERROR(ENOMEM);

    // save the file position for the packet, include block type

    position = avio_tell(pb) - 1;

    vidbuf_start[vidbuf_nbytes++] = block_type;

    // get the video delay (next int16), and set the presentation time

    vid->video_pts += vid->bethsoft_global_delay + avio_rl16(pb);

    // set the y offset if it exists (decoder header data should be in data section)

    if(block_type == VIDEO_YOFF_P_FRAME){

        if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2)

            goto fail;

        vidbuf_nbytes += 2;

    }

    do{

        vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);

        if(!vidbuf_start)

            return AVERROR(ENOMEM);

        code = avio_r8(pb);

        vidbuf_start[vidbuf_nbytes++] = code;

        if(code >= 0x80){ // rle sequence

            if(block_type == VIDEO_I_FRAME)

                vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);

        } else if(code){ // plain sequence

            if(avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code)

                goto fail;

            vidbuf_nbytes += code;

        }

        bytes_copied += code & 0x7F;

        if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied

            // may contain a 0 byte even if read all pixels

            if(avio_r8(pb))

                avio_seek(pb, -1, SEEK_CUR);

            break;

        }

        if(bytes_copied > npixels)

            goto fail;

    } while(code);

    // copy data into packet

    if(av_new_packet(pkt, vidbuf_nbytes) < 0)

        goto fail;

    memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);

    av_free(vidbuf_start);

    pkt->pos = position;

    pkt->stream_index = 0;  // use the video decoder, which was initialized as the first stream

    pkt->pts = vid->video_pts;

    vid->nframes--;  // used to check if all the frames were read

    return vidbuf_nbytes;

fail:

    av_free(vidbuf_start);

    return -1;

}

static int vid_read_packet(AVFormatContext *s,

                           AVPacket *pkt)

{

    BVID_DemuxContext *vid = s->priv_data;

    AVIOContext *pb = s->pb;

    unsigned char block_type;

    int audio_length;

    int ret_value;

    if(vid->is_finished || pb->eof_reached)

        return AVERROR(EIO);

    block_type = avio_r8(pb);

    switch(block_type){

        case PALETTE_BLOCK:

            avio_seek(pb, -1, SEEK_CUR);     // include block type

            ret_value = av_get_packet(pb, pkt, 3 * 256 + 1);

            if(ret_value != 3 * 256 + 1){

                av_free_packet(pkt);

                return AVERROR(EIO);

            }

            pkt->stream_index = 0;

            return ret_value;

        case FIRST_AUDIO_BLOCK:

            avio_rl16(pb);

            // soundblaster DAC used for sample rate, as on specification page (link above)

            s->streams[1]->codec->sample_rate = 1000000 / (256 - avio_r8(pb));

            s->streams[1]->codec->bit_rate = s->streams[1]->codec->channels * s->streams[1]->codec->sample_rate * s->streams[1]->codec->bits_per_coded_sample;

        case AUDIO_BLOCK:

            audio_length = avio_rl16(pb);

            ret_value = av_get_packet(pb, pkt, audio_length);

            pkt->stream_index = 1;

            return ret_value != audio_length ? AVERROR(EIO) : ret_value;

        case VIDEO_P_FRAME:

        case VIDEO_YOFF_P_FRAME:

        case VIDEO_I_FRAME:

            return read_frame(vid, pb, pkt, block_type, s,

                              s->streams[0]->codec->width * s->streams[0]->codec->height);

        case EOF_BLOCK:

            if(vid->nframes != 0)

                av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");

            vid->is_finished = 1;

            return AVERROR(EIO);

        default:

            av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",

                   block_type, block_type, block_type); return -1;

    }

    return 0;

}

AVInputFormat ff_bethsoftvid_demuxer = {

    "bethsoftvid",

    NULL_IF_CONFIG_SMALL("Bethesda Softworks VID format"),

    sizeof(BVID_DemuxContext),

    vid_probe,

    vid_read_header,

    vid_read_packet,

};