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ffmpeg / libavcodec / eatgv.c @ 9106a698

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/*
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 * Electronic Arts TGV Video Decoder
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 * Copyright (c) 2007-2008 Peter Ross
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
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/**
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 * @file libavcodec/eatgv.c
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 * Electronic Arts TGV Video Decoder
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 * by Peter Ross (suxen_drol at hotmail dot com)
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 *
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 * Technical details here:
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 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
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 */
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#include "avcodec.h"
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#define ALT_BITSTREAM_READER_LE
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#include "get_bits.h"
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#include "libavutil/lzo.h"
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#define EA_PREAMBLE_SIZE    8
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#define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
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typedef struct TgvContext {
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    AVCodecContext *avctx;
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    AVFrame frame;
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    AVFrame last_frame;
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    int width,height;
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    unsigned int palette[AVPALETTE_COUNT];
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    int (*mv_codebook)[2];
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    unsigned char (*block_codebook)[16];
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    int num_mvs;           ///< current length of mv_codebook
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    int num_blocks_packed; ///< current length of block_codebook
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} TgvContext;
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static av_cold int tgv_decode_init(AVCodecContext *avctx){
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    TgvContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    avctx->time_base = (AVRational){1, 15};
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    return 0;
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}
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/**
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 * Unpack buffer
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 * @return 0 on success, -1 on critical buffer underflow
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 */
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static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
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    unsigned char *dst_end = dst + width*height;
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    int size, size1, size2, av_uninit(offset), run;
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    unsigned char *dst_start = dst;
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    if (src[0] & 0x01)
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        src += 5;
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    else
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        src += 2;
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    if (src+3>src_end)
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        return -1;
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    size = AV_RB24(src);
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    src += 3;
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    while(size>0 && src<src_end) {
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        /* determine size1 and size2 */
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        size1 = (src[0] & 3);
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        if ( src[0] & 0x80 ) {  // 1
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            if (src[0] & 0x40 ) {  // 11
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                if ( src[0] & 0x20 ) {  // 111
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                    if ( src[0] < 0xFC )  // !(111111)
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                        size1 = (((src[0] & 31) + 1) << 2);
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                    src++;
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                    size2 = 0;
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                } else {  // 110
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                    offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
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                    size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
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                    src += 4;
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                }
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            } else {  // 10
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                size1 = ( ( src[1] & 0xC0) >> 6 );
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                offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
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                size2 = (src[0] & 0x3F) + 4;
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                src += 3;
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            }
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        } else {  // 0
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            offset = ((src[0] & 0x60) << 3) + src[1] + 1;
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            size2 = ((src[0] & 0x1C) >> 2) + 3;
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            src += 2;
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        }
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        /* fetch strip from src */
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        if (size1>src_end-src)
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            break;
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        if (size1>0) {
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            size -= size1;
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            run = FFMIN(size1, dst_end-dst);
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            memcpy(dst, src, run);
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            dst += run;
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            src += run;
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        }
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        if (size2>0) {
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            if (dst-dst_start<offset)
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                return 0;
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            size -= size2;
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            run = FFMIN(size2, dst_end-dst);
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            av_memcpy_backptr(dst, offset, run);
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            dst += run;
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        }
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    }
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    return 0;
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}
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/**
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 * Decode inter-frame
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 * @return 0 on success, -1 on critical buffer underflow
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 */
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static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
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    unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
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    int num_mvs;
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    int num_blocks_raw;
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    int num_blocks_packed;
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    int vector_bits;
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    int i,j,x,y;
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    GetBitContext gb;
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    int mvbits;
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    const unsigned char *blocks_raw;
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    if(buf+12>buf_end)
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        return -1;
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    num_mvs           = AV_RL16(&buf[0]);
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    num_blocks_raw    = AV_RL16(&buf[2]);
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    num_blocks_packed = AV_RL16(&buf[4]);
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    vector_bits       = AV_RL16(&buf[6]);
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    buf += 12;
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    /* allocate codebook buffers as neccessary */
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    if (num_mvs > s->num_mvs) {
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        s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
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        s->num_mvs = num_mvs;
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    }
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    if (num_blocks_packed > s->num_blocks_packed) {
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        s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
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        s->num_blocks_packed = num_blocks_packed;
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    }
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    /* read motion vectors */
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    mvbits = (num_mvs*2*10+31) & ~31;
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    if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
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        return -1;
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    init_get_bits(&gb, buf, mvbits);
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    for (i=0; i<num_mvs; i++) {
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        s->mv_codebook[i][0] = get_sbits(&gb, 10);
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        s->mv_codebook[i][1] = get_sbits(&gb, 10);
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    }
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    buf += mvbits>>3;
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    /* note ptr to uncompressed blocks */
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    blocks_raw = buf;
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    buf += num_blocks_raw*16;
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    /* read compressed blocks */
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    init_get_bits(&gb, buf, (buf_end-buf)<<3);
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    for (i=0; i<num_blocks_packed; i++) {
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        int tmp[4];
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        for(j=0; j<4; j++)
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            tmp[j] = get_bits(&gb, 8);
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        for(j=0; j<16; j++)
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            s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
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    }
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    /* read vectors and build frame */
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    for(y=0; y<s->avctx->height/4; y++)
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    for(x=0; x<s->avctx->width/4; x++) {
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        unsigned int vector = get_bits(&gb, vector_bits);
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        const unsigned char *src;
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        int src_stride;
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        if (vector < num_mvs) {
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            src = s->last_frame.data[0] +
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                  (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
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                   x*4 + s->mv_codebook[vector][0];
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            src_stride = s->last_frame.linesize[0];
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            if (src+3*src_stride+3>=frame0_end)
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                continue;
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        }else{
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            int offset = vector - num_mvs;
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            if (offset<num_blocks_raw)
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                src = blocks_raw + 16*offset;
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            else if (offset-num_blocks_raw<num_blocks_packed)
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                src = s->block_codebook[offset-num_blocks_raw];
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            else
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                continue;
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            src_stride = 4;
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        }
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        for(j=0; j<4; j++)
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        for(i=0; i<4; i++)
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            s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i)  ] =
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               src[j*src_stride + i];
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    }
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    return 0;
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}
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/** release AVFrame buffers if allocated */
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static void cond_release_buffer(AVFrame *pic)
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{
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    if (pic->data[0]) {
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        av_freep(&pic->data[0]);
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        av_free(pic->data[1]);
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    }
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}
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static int tgv_decode_frame(AVCodecContext *avctx,
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                            void *data, int *data_size,
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                            AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    TgvContext *s = avctx->priv_data;
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    const uint8_t *buf_end = buf + buf_size;
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    int chunk_type;
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    chunk_type = AV_RL32(&buf[0]);
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    buf += EA_PREAMBLE_SIZE;
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    if (chunk_type==kVGT_TAG) {
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        int pal_count, i;
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        if(buf+12>buf_end) {
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            av_log(avctx, AV_LOG_WARNING, "truncated header\n");
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            return -1;
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        }
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        s->width  = AV_RL16(&buf[0]);
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        s->height = AV_RL16(&buf[2]);
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        if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
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            avcodec_set_dimensions(s->avctx, s->width, s->height);
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            cond_release_buffer(&s->frame);
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            cond_release_buffer(&s->last_frame);
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        }
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        pal_count = AV_RL16(&buf[6]);
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        buf += 12;
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        for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
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            s->palette[i] = AV_RB24(buf);
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            buf += 3;
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        }
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    }
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    if (avcodec_check_dimensions(avctx, s->width, s->height))
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        return -1;
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    /* shuffle */
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    FFSWAP(AVFrame, s->frame, s->last_frame);
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    if (!s->frame.data[0]) {
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        s->frame.reference = 1;
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        s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
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        s->frame.linesize[0] = s->width;
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        /* allocate additional 12 bytes to accomodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
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        s->frame.data[0] = av_malloc(s->width*s->height + 12);
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        if (!s->frame.data[0])
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            return AVERROR_NOMEM;
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        s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
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        if (!s->frame.data[1]) {
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            av_freep(&s->frame.data[0]);
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            return AVERROR_NOMEM;
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        }
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    }
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    memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
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    if(chunk_type==kVGT_TAG) {
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        s->frame.key_frame = 1;
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        s->frame.pict_type = FF_I_TYPE;
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        if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
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            av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
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            return -1;
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        }
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    }else{
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        if (!s->last_frame.data[0]) {
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            av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
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            return buf_size;
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        }
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        s->frame.key_frame = 0;
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        s->frame.pict_type = FF_P_TYPE;
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        if (tgv_decode_inter(s, buf, buf_end)<0) {
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            av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
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            return -1;
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        }
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = s->frame;
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    return buf_size;
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}
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static av_cold int tgv_decode_end(AVCodecContext *avctx)
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{
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    TgvContext *s = avctx->priv_data;
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    cond_release_buffer(&s->frame);
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    cond_release_buffer(&s->last_frame);
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    av_free(s->mv_codebook);
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    av_free(s->block_codebook);
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    return 0;
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}
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AVCodec eatgv_decoder = {
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    "eatgv",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_TGV,
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    sizeof(TgvContext),
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    tgv_decode_init,
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    NULL,
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    tgv_decode_end,
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    tgv_decode_frame,
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    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
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};