PeerStreamer

/*

 * Feeble Files/ScummVM DXA decoder

 * 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

 */

/**

 * @file libavcodec/dxa.c

 * DXA Video decoder

 */

#include <stdio.h>

#include <stdlib.h>

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

#include <zlib.h>

/*

 * Decoder context

 */

typedef struct DxaDecContext {

    AVCodecContext *avctx;

    AVFrame pic, prev;

    int dsize;

    uint8_t *decomp_buf;

    uint32_t pal[256];

} DxaDecContext;

static const int shift1[6] = { 0, 8, 8, 8, 4, 4 };

static const int shift2[6] = { 0, 0, 8, 4, 0, 4 };

static int decode_13(AVCodecContext *avctx, DxaDecContext *c, uint8_t* dst, uint8_t *src, uint8_t *ref)

{

    uint8_t *code, *data, *mv, *msk, *tmp, *tmp2;

    int i, j, k;

    int type, x, y, d, d2;

    int stride = c->pic.linesize[0];

    uint32_t mask;

    code = src  + 12;

    data = code + ((avctx->width * avctx->height) >> 4);

    mv   = data + AV_RB32(src + 0);

    msk  = mv   + AV_RB32(src + 4);

    for(j = 0; j < avctx->height; j += 4){

        for(i = 0; i < avctx->width; i += 4){

            tmp  = dst + i;

            tmp2 = ref + i;

            type = *code++;

            switch(type){

            case 4: // motion compensation

                x = (*mv) >> 4;    if(x & 8) x = 8 - x;

                y = (*mv++) & 0xF; if(y & 8) y = 8 - y;

                tmp2 += x + y*stride;

            case 0: // skip

            case 5: // skip in method 12

                for(y = 0; y < 4; y++){

                    memcpy(tmp, tmp2, 4);

                    tmp  += stride;

                    tmp2 += stride;

                }

                break;

            case 1:  // masked change

            case 10: // masked change with only half of pixels changed

            case 11: // cases 10-15 are for method 12 only

            case 12:

            case 13:

            case 14:

            case 15:

                if(type == 1){

                    mask = AV_RB16(msk);

                    msk += 2;

                }else{

                    type -= 10;

                    mask = ((msk[0] & 0xF0) << shift1[type]) | ((msk[0] & 0xF) << shift2[type]);

                    msk++;

                }

                for(y = 0; y < 4; y++){

                    for(x = 0; x < 4; x++){

                        tmp[x] = (mask & 0x8000) ? *data++ : tmp2[x];

                        mask <<= 1;

                    }

                    tmp  += stride;

                    tmp2 += stride;

                }

                break;

            case 2: // fill block

                for(y = 0; y < 4; y++){

                    memset(tmp, data[0], 4);

                    tmp += stride;

                }

                data++;

                break;

            case 3: // raw block

                for(y = 0; y < 4; y++){

                    memcpy(tmp, data, 4);

                    data += 4;

                    tmp  += stride;

                }

                break;

            case 8: // subblocks - method 13 only

                mask = *msk++;

                for(k = 0; k < 4; k++){

                    d  = ((k & 1) << 1) + ((k & 2) * stride);

                    d2 = ((k & 1) << 1) + ((k & 2) * stride);

                    tmp2 = ref + i + d2;

                    switch(mask & 0xC0){

                    case 0x80: // motion compensation

                        x = (*mv) >> 4;    if(x & 8) x = 8 - x;

                        y = (*mv++) & 0xF; if(y & 8) y = 8 - y;

                        tmp2 += x + y*stride;

                    case 0x00: // skip

                        tmp[d + 0         ] = tmp2[0];

                        tmp[d + 1         ] = tmp2[1];

                        tmp[d + 0 + stride] = tmp2[0 + stride];

                        tmp[d + 1 + stride] = tmp2[1 + stride];

                        break;

                    case 0x40: // fill

                        tmp[d + 0         ] = data[0];

                        tmp[d + 1         ] = data[0];

                        tmp[d + 0 + stride] = data[0];

                        tmp[d + 1 + stride] = data[0];

                        data++;

                        break;

                    case 0xC0: // raw

                        tmp[d + 0         ] = *data++;

                        tmp[d + 1         ] = *data++;

                        tmp[d + 0 + stride] = *data++;

                        tmp[d + 1 + stride] = *data++;

                        break;

                    }

                    mask <<= 2;

                }

                break;

            case 32: // vector quantization - 2 colors

                mask = AV_RB16(msk);

                msk += 2;

                for(y = 0; y < 4; y++){

                    for(x = 0; x < 4; x++){

                        tmp[x] = data[mask & 1];

                        mask >>= 1;

                    }

                    tmp  += stride;

                    tmp2 += stride;

                }

                data += 2;

                break;

            case 33: // vector quantization - 3 or 4 colors

            case 34:

                mask = AV_RB32(msk);

                msk += 4;

                for(y = 0; y < 4; y++){

                    for(x = 0; x < 4; x++){

                        tmp[x] = data[mask & 3];

                        mask >>= 2;

                    }

                    tmp  += stride;

                    tmp2 += stride;

                }

                data += type - 30;

                break;

            default:

                av_log(avctx, AV_LOG_ERROR, "Unknown opcode %d\n", type);

                return -1;

            }

        }

        dst += stride * 4;

        ref += stride * 4;

    }

    return 0;

}

static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    DxaDecContext * const c = avctx->priv_data;

    uint8_t *outptr, *srcptr, *tmpptr;

    unsigned long dsize;

    int i, j, compr;

    int stride;

    int orig_buf_size = buf_size;

    int pc = 0;

    /* make the palette available on the way out */

    if(buf[0]=='C' && buf[1]=='M' && buf[2]=='A' && buf[3]=='P'){

        int r, g, b;

        buf += 4;

        for(i = 0; i < 256; i++){

            r = *buf++;

            g = *buf++;

            b = *buf++;

            c->pal[i] = (r << 16) | (g << 8) | b;

        }

        pc = 1;

        buf_size -= 768+4;

    }

    if(avctx->get_buffer(avctx, &c->pic) < 0){

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

        return -1;

    }

    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);

    c->pic.palette_has_changed = pc;

    outptr = c->pic.data[0];

    srcptr = c->decomp_buf;

    tmpptr = c->prev.data[0];

    stride = c->pic.linesize[0];

    if(buf[0]=='N' && buf[1]=='U' && buf[2]=='L' && buf[3]=='L')

        compr = -1;

    else

        compr = buf[4];

    dsize = c->dsize;

    if((compr != 4 && compr != -1) && uncompress(c->decomp_buf, &dsize, buf + 9, buf_size - 9) != Z_OK){

        av_log(avctx, AV_LOG_ERROR, "Uncompress failed!\n");

        return -1;

    }

    switch(compr){

    case -1:

        c->pic.key_frame = 0;

        c->pic.pict_type = FF_P_TYPE;

        if(c->prev.data[0])

            memcpy(c->pic.data[0], c->prev.data[0], c->pic.linesize[0] * avctx->height);

        else{ // Should happen only when first frame is 'NULL'

            memset(c->pic.data[0], 0, c->pic.linesize[0] * avctx->height);

            c->pic.key_frame = 1;

            c->pic.pict_type = FF_I_TYPE;

        }

        break;

    case 2:

    case 3:

    case 4:

    case 5:

        c->pic.key_frame = !(compr & 1);

        c->pic.pict_type = (compr & 1) ? FF_P_TYPE : FF_I_TYPE;

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

            if(compr & 1){

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

                    outptr[i] = srcptr[i] ^ tmpptr[i];

                tmpptr += stride;

            }else

                memcpy(outptr, srcptr, avctx->width);

            outptr += stride;

            srcptr += avctx->width;

        }

        break;

    case 12: // ScummVM coding

    case 13:

        c->pic.key_frame = 0;

        c->pic.pict_type = FF_P_TYPE;

        decode_13(avctx, c, c->pic.data[0], srcptr, c->prev.data[0]);

        break;

    default:

        av_log(avctx, AV_LOG_ERROR, "Unknown/unsupported compression type %d\n", buf[4]);

        return -1;

    }

    FFSWAP(AVFrame, c->pic, c->prev);

    if(c->pic.data[0])

        avctx->release_buffer(avctx, &c->pic);

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = c->prev;

    /* always report that the buffer was completely consumed */

    return orig_buf_size;

}

static av_cold int decode_init(AVCodecContext *avctx)

{

    DxaDecContext * const c = avctx->priv_data;

    c->avctx = avctx;

    avctx->pix_fmt = PIX_FMT_PAL8;

    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {

        return -1;

    }

    c->dsize = avctx->width * avctx->height * 2;

    if((c->decomp_buf = av_malloc(c->dsize)) == NULL) {

        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");

        return -1;

    }

    return 0;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    DxaDecContext * const c = avctx->priv_data;

    av_freep(&c->decomp_buf);

    if(c->prev.data[0])

        avctx->release_buffer(avctx, &c->prev);

    if(c->pic.data[0])

        avctx->release_buffer(avctx, &c->pic);

    return 0;

}

AVCodec dxa_decoder = {

    "dxa",

    CODEC_TYPE_VIDEO,

    CODEC_ID_DXA,

    sizeof(DxaDecContext),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Feeble Files/ScummVM DXA"),

};