PeerStreamer

/*

 * Brute Force & Ignorance (BFI) video decoder

 * Copyright (c) 2008 Sisir Koppaka

 *

 * 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

 */

/**

 * @file

 * @brief Brute Force & Ignorance (.bfi) video decoder

 * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )

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

 */

#include "libavutil/common.h"

#include "avcodec.h"

#include "bytestream.h"

typedef struct BFIContext {

    AVCodecContext *avctx;

    AVFrame frame;

    uint8_t *dst;

} BFIContext;

static av_cold int bfi_decode_init(AVCodecContext * avctx)

{

    BFIContext *bfi = avctx->priv_data;

    avctx->pix_fmt = PIX_FMT_PAL8;

    bfi->dst = av_mallocz(avctx->width * avctx->height);

    return 0;

}

static int bfi_decode_frame(AVCodecContext * avctx, void *data,

                            int *data_size, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data, *buf_end = avpkt->data + avpkt->size;

    int buf_size = avpkt->size;

    BFIContext *bfi = avctx->priv_data;

    uint8_t *dst = bfi->dst;

    uint8_t *src, *dst_offset, colour1, colour2;

    uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;

    uint32_t *pal;

    int i, j, height = avctx->height;

    if (bfi->frame.data[0])

        avctx->release_buffer(avctx, &bfi->frame);

    bfi->frame.reference = 1;

    if (avctx->get_buffer(avctx, &bfi->frame) < 0) {

        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

        return -1;

    }

    /* Set frame parameters and palette, if necessary */

    if (!avctx->frame_number) {

        bfi->frame.pict_type = FF_I_TYPE;

        bfi->frame.key_frame = 1;

        /* Setting the palette */

        if(avctx->extradata_size>768) {

            av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");

            return -1;

        }

        pal = (uint32_t *) bfi->frame.data[1];

        for (i = 0; i < avctx->extradata_size / 3; i++) {

            int shift = 16;

            *pal = 0;

            for (j = 0; j < 3; j++, shift -= 8)

                *pal +=

                    ((avctx->extradata[i * 3 + j] << 2) |

                    (avctx->extradata[i * 3 + j] >> 4)) << shift;

            pal++;

        }

        bfi->frame.palette_has_changed = 1;

    } else {

        bfi->frame.pict_type = FF_P_TYPE;

        bfi->frame.key_frame = 0;

    }

    buf += 4; //Unpacked size, not required.

    while (dst != frame_end) {

        static const uint8_t lentab[4]={0,2,0,1};

        unsigned int byte = *buf++, av_uninit(offset);

        unsigned int code = byte >> 6;

        unsigned int length = byte & ~0xC0;

        if (buf >= buf_end) {

            av_log(avctx, AV_LOG_ERROR, "Input resolution larger than actual frame.\n");

            return -1;

        }

        /* Get length and offset(if required) */

        if (length == 0) {

            if (code == 1) {

                length = bytestream_get_byte(&buf);

                offset = bytestream_get_le16(&buf);

            } else {

                length = bytestream_get_le16(&buf);

                if (code == 2 && length == 0)

                    break;

            }

        } else {

            if (code == 1)

                offset = bytestream_get_byte(&buf);

        }

        /* Do boundary check */

        if (dst + (length<<lentab[code]) > frame_end)

            break;

        switch (code) {

        case 0:                //Normal Chain

            if (length >= buf_end - buf) {

                av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");

                return -1;

            }

            bytestream_get_buffer(&buf, dst, length);

            dst += length;

            break;

        case 1:                //Back Chain

            dst_offset = dst - offset;

            length *= 4;        //Convert dwords to bytes.

            if (dst_offset < bfi->dst)

                break;

            while (length--)

                *dst++ = *dst_offset++;

            break;

        case 2:                //Skip Chain

            dst += length;

            break;

        case 3:                //Fill Chain

            colour1 = bytestream_get_byte(&buf);

            colour2 = bytestream_get_byte(&buf);

            while (length--) {

                *dst++ = colour1;

                *dst++ = colour2;

            }

            break;

        }

    }

    src = bfi->dst;

    dst = bfi->frame.data[0];

    while (height--) {

        memcpy(dst, src, avctx->width);

        src += avctx->width;

        dst += bfi->frame.linesize[0];

    }

    *data_size = sizeof(AVFrame);

    *(AVFrame *) data = bfi->frame;

    return buf_size;

}

static av_cold int bfi_decode_close(AVCodecContext * avctx)

{

    BFIContext *bfi = avctx->priv_data;

    if (bfi->frame.data[0])

        avctx->release_buffer(avctx, &bfi->frame);

    av_free(bfi->dst);

    return 0;

}

AVCodec ff_bfi_decoder = {

    .name = "bfi",

    .type = AVMEDIA_TYPE_VIDEO,

    .id = CODEC_ID_BFI,

    .priv_data_size = sizeof(BFIContext),

    .init = bfi_decode_init,

    .close = bfi_decode_close,

    .decode = bfi_decode_frame,

    .capabilities = CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),

};