PeerStreamer

/*

 * Bitmap Brothers JV video decoder

 * Copyright (c) 2011 Peter Ross <pross@xvid.org>

 *

 * 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

 * Bitmap Brothers JV video decoder

 * @author Peter Ross <pross@xvid.org>

 */

#include "avcodec.h"

#include "dsputil.h"

#include "get_bits.h"

#include "libavutil/intreadwrite.h"

typedef struct JvContext {

    DSPContext dsp;

    AVFrame    frame;

    uint32_t   palette[AVPALETTE_COUNT];

    int        palette_has_changed;

} JvContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    JvContext *s = avctx->priv_data;

    avctx->pix_fmt = PIX_FMT_PAL8;

    dsputil_init(&s->dsp, avctx);

    return 0;

}

/**

 * Decode 2x2 block

 */

static inline void decode2x2(GetBitContext *gb, uint8_t *dst, int linesize)

{

    int i, j, v[2];

    switch (get_bits(gb, 2)) {

    case 1:

        v[0] = get_bits(gb, 8);

        for (j = 0; j < 2; j++)

            memset(dst + j*linesize, v[0], 2);

        break;

    case 2:

        v[0] = get_bits(gb, 8);

        v[1] = get_bits(gb, 8);

        for (j = 0; j < 2; j++)

            for (i = 0; i < 2; i++)

                dst[j*linesize + i] = v[get_bits1(gb)];

        break;

    case 3:

        for (j = 0; j < 2; j++)

            for (i = 0; i < 2; i++)

                dst[j*linesize + i] = get_bits(gb, 8);

    }

}

/**

 * Decode 4x4 block

 */

static inline void decode4x4(GetBitContext *gb, uint8_t *dst, int linesize)

{

    int i, j, v[2];

    switch (get_bits(gb, 2)) {

    case 1:

        v[0] = get_bits(gb, 8);

        for (j = 0; j < 4; j++)

            memset(dst + j*linesize, v[0], 4);

        break;

    case 2:

        v[0] = get_bits(gb, 8);

        v[1] = get_bits(gb, 8);

        for (j = 2; j >= 0; j -= 2) {

            for (i = 0; i < 4; i++)

                dst[j*linesize + i]     = v[get_bits1(gb)];

            for (i = 0; i < 4; i++)

                dst[(j+1)*linesize + i] = v[get_bits1(gb)];

        }

        break;

    case 3:

        for (j = 0; j < 4; j += 2)

            for (i = 0; i < 4; i += 2)

                decode2x2(gb, dst + j*linesize + i, linesize);

    }

}

/**

 * Decode 8x8 block

 */

static inline void decode8x8(GetBitContext *gb, uint8_t *dst, int linesize, DSPContext *dsp)

{

    int i, j, v[2];

    switch (get_bits(gb, 2)) {

    case 1:

        v[0] = get_bits(gb, 8);

        dsp->fill_block_tab[1](dst, v[0], linesize, 8);

        break;

    case 2:

        v[0] = get_bits(gb, 8);

        v[1] = get_bits(gb, 8);

        for (j = 7; j >= 0; j--)

            for (i = 0; i <  8; i++)

                dst[j*linesize + i] = v[get_bits1(gb)];

        break;

    case 3:

        for (j = 0; j < 8; j += 4)

            for (i = 0; i < 8; i += 4)

                decode4x4(gb, dst + j*linesize + i, linesize);

    }

}

static int decode_frame(AVCodecContext *avctx,

                        void *data, int *data_size,

                        AVPacket *avpkt)

{

    JvContext *s           = avctx->priv_data;

    int buf_size           = avpkt->size;

    const uint8_t *buf     = avpkt->data;

    const uint8_t *buf_end = buf + buf_size;

    int video_size, video_type, i, j;

    video_size = AV_RL32(buf);

    video_type = buf[4];

    buf += 5;

    if (video_size) {

        if (avctx->reget_buffer(avctx, &s->frame) < 0) {

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

            return -1;

        }

        if (video_type == 0 || video_type == 1) {

            GetBitContext gb;

            init_get_bits(&gb, buf, FFMIN(video_size, buf_end - buf));

            for (j = 0; j < avctx->height; j += 8)

                for (i = 0; i < avctx->width; i += 8)

                    decode8x8(&gb, s->frame.data[0] + j*s->frame.linesize[0] + i,

                              s->frame.linesize[0], &s->dsp);

            buf += video_size;

        } else if (video_type == 2) {

            if (buf + 1 <= buf_end) {

                int v = *buf++;

                for (j = 0; j < avctx->height; j++)

                    memset(s->frame.data[0] + j*s->frame.linesize[0], v, avctx->width);

            }

        } else {

            av_log(avctx, AV_LOG_WARNING, "unsupported frame type %i\n", video_type);

            return AVERROR_INVALIDDATA;

        }

    }

    if (buf < buf_end) {

        for (i = 0; i < AVPALETTE_COUNT && buf + 3 <= buf_end; i++) {

            s->palette[i] = AV_RB24(buf) << 2;

            buf += 3;

        }

        s->palette_has_changed = 1;

    }

    if (video_size) {

        s->frame.key_frame           = 1;

        s->frame.pict_type           = FF_I_TYPE;

        s->frame.palette_has_changed = s->palette_has_changed;

        s->palette_has_changed       = 0;

        memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);

        *data_size      = sizeof(AVFrame);

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

    }

    return buf_size;

}

static av_cold int decode_close(AVCodecContext *avctx)

{

    JvContext *s = avctx->priv_data;

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

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

    return 0;

}

AVCodec ff_jv_decoder = {

    .name           = "jv",

    .long_name      = NULL_IF_CONFIG_SMALL("Bitmap Brothers JV video"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = CODEC_ID_JV,

    .priv_data_size = sizeof(JvContext),

    .init           = decode_init,

    .close          = decode_close,

    .decode         = decode_frame,

    .capabilities   = CODEC_CAP_DR1,

};