GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/yop.c Lines: 84 102 82.4 %
Date: 2020-09-25 23:16:12 Branches: 30 44 68.2 %

Line Branch Exec Source
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/*
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 * Psygnosis YOP decoder
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 *
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 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
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 * derived from the code by
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 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
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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 Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <string.h>
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#include "libavutil/imgutils.h"
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#include "libavutil/internal.h"
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "internal.h"
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typedef struct YopDecContext {
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    AVCodecContext *avctx;
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    AVFrame *frame;
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    int num_pal_colors;
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    int first_color[2];
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    int frame_data_length;
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    uint8_t *low_nibble;
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    uint8_t *srcptr;
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    uint8_t *src_end;
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    uint8_t *dstptr;
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    uint8_t *dstbuf;
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} YopDecContext;
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// These tables are taken directly from:
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// http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
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/**
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 * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
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 * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
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 * Byte 3 contains the number of bytes consumed on the input,
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 * equal to max(bytes 0-2) + 1.
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 */
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static const uint8_t paint_lut[15][4] =
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    {{1, 2, 3, 4}, {1, 2, 0, 3},
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     {1, 2, 1, 3}, {1, 2, 2, 3},
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     {1, 0, 2, 3}, {1, 0, 0, 2},
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     {1, 0, 1, 2}, {1, 1, 2, 3},
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     {0, 1, 2, 3}, {0, 1, 0, 2},
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     {1, 1, 0, 2}, {0, 1, 1, 2},
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     {0, 0, 1, 2}, {0, 0, 0, 1},
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     {1, 1, 1, 2},
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    };
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/**
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 * Lookup table for copying macroblocks. Each entry contains the respective
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 * x and y pixel offset for the copy source.
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 */
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static const int8_t motion_vector[16][2] =
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    {{-4, -4}, {-2, -4},
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     { 0, -4}, { 2, -4},
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     {-4, -2}, {-4,  0},
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     {-3, -3}, {-1, -3},
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     { 1, -3}, { 3, -3},
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     {-3, -1}, {-2, -2},
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     { 0, -2}, { 2, -2},
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     { 4, -2}, {-2,  0},
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    };
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static av_cold int yop_decode_close(AVCodecContext *avctx)
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{
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    YopDecContext *s = avctx->priv_data;
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    av_frame_free(&s->frame);
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    return 0;
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}
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static av_cold int yop_decode_init(AVCodecContext *avctx)
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{
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    YopDecContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    if (avctx->width & 1 || avctx->height & 1 ||
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        av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
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        av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
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        return AVERROR_INVALIDDATA;
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    }
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    if (avctx->extradata_size < 3) {
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        av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata.\n");
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        return AVERROR_INVALIDDATA;
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    }
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2
    avctx->pix_fmt = AV_PIX_FMT_PAL8;
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    s->num_pal_colors = avctx->extradata[0];
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2
    s->first_color[0] = avctx->extradata[1];
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2
    s->first_color[1] = avctx->extradata[2];
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2
    if (s->num_pal_colors + s->first_color[0] > 256 ||
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        s->num_pal_colors + s->first_color[1] > 256) {
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        av_log(avctx, AV_LOG_ERROR,
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               "Palette parameters invalid, header probably corrupt\n");
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        return AVERROR_INVALIDDATA;
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    }
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    s->frame = av_frame_alloc();
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2
    if (!s->frame)
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        return AVERROR(ENOMEM);
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    return 0;
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}
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/**
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 * Paint a macroblock using the pattern in paint_lut.
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 * @param s codec context
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 * @param tag the tag that was in the nibble
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 */
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76866
static int yop_paint_block(YopDecContext *s, int linesize, int tag)
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{
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76866
    if (s->src_end - s->srcptr < paint_lut[tag][3]) {
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        av_log(s->avctx, AV_LOG_ERROR, "Packet too small.\n");
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        return AVERROR_INVALIDDATA;
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    }
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76865
    s->dstptr[0]            = s->srcptr[0];
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76865
    s->dstptr[1]            = s->srcptr[paint_lut[tag][0]];
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76865
    s->dstptr[linesize]     = s->srcptr[paint_lut[tag][1]];
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76865
    s->dstptr[linesize + 1] = s->srcptr[paint_lut[tag][2]];
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    // The number of src bytes consumed is in the last part of the lut entry.
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76865
    s->srcptr += paint_lut[tag][3];
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76865
    return 0;
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}
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/**
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 * Copy a previously painted macroblock to the current_block.
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 * @param copy_tag the tag that was in the nibble
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 */
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90934
static int yop_copy_previous_block(YopDecContext *s, int linesize, int copy_tag)
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{
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    uint8_t *bufptr;
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    // Calculate position for the copy source
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90934
    bufptr = s->dstptr + motion_vector[copy_tag][0] +
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90934
             linesize * motion_vector[copy_tag][1];
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90934
    if (bufptr < s->dstbuf) {
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        av_log(s->avctx, AV_LOG_ERROR, "File probably corrupt\n");
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        return AVERROR_INVALIDDATA;
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    }
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90934
    s->dstptr[0]            = bufptr[0];
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90934
    s->dstptr[1]            = bufptr[1];
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90934
    s->dstptr[linesize]     = bufptr[linesize];
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90934
    s->dstptr[linesize + 1] = bufptr[linesize + 1];
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90934
    return 0;
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}
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/**
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 * Return the next nibble in sequence, consuming a new byte on the input
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 * only if necessary.
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 */
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258734
static uint8_t yop_get_next_nibble(YopDecContext *s)
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{
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    int ret;
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258734
    if (s->low_nibble) {
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129365
        ret           = *s->low_nibble & 0xf;
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129365
        s->low_nibble = NULL;
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    }else {
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129369
        s->low_nibble = s->srcptr++;
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129369
        ret           = *s->low_nibble >> 4;
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    }
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258734
    return ret;
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}
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static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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                            AVPacket *avpkt)
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{
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    YopDecContext *s = avctx->priv_data;
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    AVFrame *frame = s->frame;
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    int tag, firstcolor, is_odd_frame;
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    int ret, i, x, y;
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    uint32_t *palette;
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    if (avpkt->size < 4 + 3 * s->num_pal_colors) {
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        av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
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        return AVERROR_INVALIDDATA;
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    }
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    if ((ret = ff_reget_buffer(avctx, frame, 0)) < 0)
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        return ret;
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    if (!avctx->frame_number)
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1
        memset(frame->data[1], 0, AVPALETTE_SIZE);
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    s->dstbuf     = frame->data[0];
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    s->dstptr     = frame->data[0];
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    s->srcptr     = avpkt->data + 4;
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    s->src_end    = avpkt->data + avpkt->size;
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    s->low_nibble = NULL;
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    is_odd_frame = avpkt->data[0];
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    if(is_odd_frame>1){
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        av_log(avctx, AV_LOG_ERROR, "frame is too odd %d\n", is_odd_frame);
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        return AVERROR_INVALIDDATA;
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    }
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    firstcolor   = s->first_color[is_odd_frame];
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    palette      = (uint32_t *)frame->data[1];
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    for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3) {
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        palette[i + firstcolor] = (s->srcptr[0] << 18) |
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                                  (s->srcptr[1] << 10) |
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                                  (s->srcptr[2] << 2);
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        palette[i + firstcolor] |= 0xFFU << 24 |
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                                   (palette[i + firstcolor] >> 6) & 0x30303;
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    }
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    frame->palette_has_changed = 1;
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    for (y = 0; y < avctx->height; y += 2) {
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168378
        for (x = 0; x < avctx->width; x += 2) {
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167800
            if (s->srcptr - avpkt->data >= avpkt->size) {
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                av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
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                return AVERROR_INVALIDDATA;
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            }
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167800
            tag = yop_get_next_nibble(s);
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167800
            if (tag != 0xf) {
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76866
                ret = yop_paint_block(s, frame->linesize[0], tag);
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76866
                if (ret < 0)
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1
                    return ret;
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            } else {
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90934
                tag = yop_get_next_nibble(s);
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90934
                ret = yop_copy_previous_block(s, frame->linesize[0], tag);
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90934
                if (ret < 0)
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                    return ret;
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            }
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167799
            s->dstptr += 2;
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        }
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        s->dstptr += 2*frame->linesize[0] - x;
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    }
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    if ((ret = av_frame_ref(data, s->frame)) < 0)
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        return ret;
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    *got_frame = 1;
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    return avpkt->size;
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}
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AVCodec ff_yop_decoder = {
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    .name           = "yop",
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    .long_name      = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = AV_CODEC_ID_YOP,
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    .priv_data_size = sizeof(YopDecContext),
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    .init           = yop_decode_init,
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    .close          = yop_decode_close,
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    .decode         = yop_decode_frame,
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};