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/*
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 * Quicktime Video (RPZA) Video Decoder
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 * Copyright (C) 2003 the ffmpeg project
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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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/**
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 * @file
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 * QT RPZA Video Decoder by Roberto Togni
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 * For more information about the RPZA format, visit:
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 *   http://www.pcisys.net/~melanson/codecs/
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 *
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 * The RPZA decoder outputs RGB555 colorspace data.
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 *
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 * Note that this decoder reads big endian RGB555 pixel values from the
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 * bytestream, arranges them in the host's endian order, and outputs
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 * them to the final rendered map in the same host endian order. This is
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 * intended behavior as the ffmpeg documentation states that RGB555 pixels
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 * shall be stored in native CPU endianness.
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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typedef struct RpzaContext {
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    AVCodecContext *avctx;
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    AVFrame frame;
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    const unsigned char *buf;
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    int size;
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} RpzaContext;
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#define ADVANCE_BLOCK() \
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{ \
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    pixel_ptr += 4; \
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    if (pixel_ptr >= width) \
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    { \
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        pixel_ptr = 0; \
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        row_ptr += stride * 4; \
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    } \
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    total_blocks--; \
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    if (total_blocks < 0) \
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    { \
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        av_log(s->avctx, AV_LOG_ERROR, "warning: block counter just went negative (this should not happen)\n"); \
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        return; \
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    } \
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}
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static void rpza_decode_stream(RpzaContext *s)
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{
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    int width = s->avctx->width;
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    int stride = s->frame.linesize[0] / 2;
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    int row_inc = stride - 4;
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    int stream_ptr = 0;
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    int chunk_size;
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    unsigned char opcode;
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    int n_blocks;
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    unsigned short colorA = 0, colorB;
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    unsigned short color4[4];
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    unsigned char index, idx;
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    unsigned short ta, tb;
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    unsigned short *pixels = (unsigned short *)s->frame.data[0];
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    int row_ptr = 0;
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    int pixel_ptr = 0;
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    int block_ptr;
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    int pixel_x, pixel_y;
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    int total_blocks;
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    /* First byte is always 0xe1. Warn if it's different */
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    if (s->buf[stream_ptr] != 0xe1)
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        av_log(s->avctx, AV_LOG_ERROR, "First chunk byte is 0x%02x instead of 0xe1\n",
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            s->buf[stream_ptr]);
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    /* Get chunk size, ingnoring first byte */
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    chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
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    stream_ptr += 4;
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    /* If length mismatch use size from MOV file and try to decode anyway */
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    if (chunk_size != s->size)
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        av_log(s->avctx, AV_LOG_ERROR, "MOV chunk size != encoded chunk size; using MOV chunk size\n");
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    chunk_size = s->size;
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    /* Number of 4x4 blocks in frame. */
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    total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
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    /* Process chunk data */
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    while (stream_ptr < chunk_size) {
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        opcode = s->buf[stream_ptr++]; /* Get opcode */
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        n_blocks = (opcode & 0x1f) + 1; /* Extract block counter from opcode */
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        /* If opcode MSbit is 0, we need more data to decide what to do */
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        if ((opcode & 0x80) == 0) {
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            colorA = (opcode << 8) | (s->buf[stream_ptr++]);
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            opcode = 0;
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            if ((s->buf[stream_ptr] & 0x80) != 0) {
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                /* Must behave as opcode 110xxxxx, using colorA computed
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                 * above. Use fake opcode 0x20 to enter switch block at
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                 * the right place */
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                opcode = 0x20;
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                n_blocks = 1;
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            }
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        }
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        switch (opcode & 0xe0) {
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        /* Skip blocks */
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        case 0x80:
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            while (n_blocks--) {
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              ADVANCE_BLOCK();
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            }
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            break;
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        /* Fill blocks with one color */
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        case 0xa0:
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            colorA = AV_RB16 (&s->buf[stream_ptr]);
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            stream_ptr += 2;
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            while (n_blocks--) {
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                block_ptr = row_ptr + pixel_ptr;
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                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
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                    for (pixel_x = 0; pixel_x < 4; pixel_x++){
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                        pixels[block_ptr] = colorA;
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                        block_ptr++;
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                    }
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                    block_ptr += row_inc;
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                }
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                ADVANCE_BLOCK();
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            }
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            break;
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        /* Fill blocks with 4 colors */
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        case 0xc0:
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            colorA = AV_RB16 (&s->buf[stream_ptr]);
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            stream_ptr += 2;
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        case 0x20:
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            colorB = AV_RB16 (&s->buf[stream_ptr]);
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            stream_ptr += 2;
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            /* sort out the colors */
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            color4[0] = colorB;
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            color4[1] = 0;
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            color4[2] = 0;
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            color4[3] = colorA;
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            /* red components */
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            ta = (colorA >> 10) & 0x1F;
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            tb = (colorB >> 10) & 0x1F;
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            color4[1] |= ((11 * ta + 21 * tb) >> 5) << 10;
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            color4[2] |= ((21 * ta + 11 * tb) >> 5) << 10;
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            /* green components */
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            ta = (colorA >> 5) & 0x1F;
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            tb = (colorB >> 5) & 0x1F;
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            color4[1] |= ((11 * ta + 21 * tb) >> 5) << 5;
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            color4[2] |= ((21 * ta + 11 * tb) >> 5) << 5;
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            /* blue components */
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            ta = colorA & 0x1F;
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            tb = colorB & 0x1F;
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            color4[1] |= ((11 * ta + 21 * tb) >> 5);
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            color4[2] |= ((21 * ta + 11 * tb) >> 5);
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            while (n_blocks--) {
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                block_ptr = row_ptr + pixel_ptr;
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                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
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                    index = s->buf[stream_ptr++];
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                    for (pixel_x = 0; pixel_x < 4; pixel_x++){
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                        idx = (index >> (2 * (3 - pixel_x))) & 0x03;
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                        pixels[block_ptr] = color4[idx];
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                        block_ptr++;
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                    }
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                    block_ptr += row_inc;
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                }
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                ADVANCE_BLOCK();
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            }
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            break;
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        /* Fill block with 16 colors */
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        case 0x00:
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            block_ptr = row_ptr + pixel_ptr;
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            for (pixel_y = 0; pixel_y < 4; pixel_y++) {
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                for (pixel_x = 0; pixel_x < 4; pixel_x++){
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                    /* We already have color of upper left pixel */
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                    if ((pixel_y != 0) || (pixel_x !=0)) {
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                        colorA = AV_RB16 (&s->buf[stream_ptr]);
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                        stream_ptr += 2;
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                    }
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                    pixels[block_ptr] = colorA;
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                    block_ptr++;
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                }
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                block_ptr += row_inc;
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            }
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            ADVANCE_BLOCK();
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            break;
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        /* Unknown opcode */
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        default:
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            av_log(s->avctx, AV_LOG_ERROR, "Unknown opcode %d in rpza chunk."
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                 " Skip remaining %d bytes of chunk data.\n", opcode,
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                 chunk_size - stream_ptr);
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            return;
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        } /* Opcode switch */
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    }
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}
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static av_cold int rpza_decode_init(AVCodecContext *avctx)
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{
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    RpzaContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    avctx->pix_fmt = PIX_FMT_RGB555;
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    s->frame.data[0] = NULL;
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    return 0;
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}
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static int rpza_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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    RpzaContext *s = avctx->priv_data;
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    s->buf = buf;
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    s->size = buf_size;
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    s->frame.reference = 1;
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    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
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    if (avctx->reget_buffer(avctx, &s->frame)) {
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        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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        return -1;
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    }
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    rpza_decode_stream(s);
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = s->frame;
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    /* always report that the buffer was completely consumed */
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    return buf_size;
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}
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static av_cold int rpza_decode_end(AVCodecContext *avctx)
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{
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    RpzaContext *s = avctx->priv_data;
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    if (s->frame.data[0])
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        avctx->release_buffer(avctx, &s->frame);
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    return 0;
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}
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AVCodec ff_rpza_decoder = {
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    "rpza",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_RPZA,
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    sizeof(RpzaContext),
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    rpza_decode_init,
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    NULL,
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    rpza_decode_end,
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    rpza_decode_frame,
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    CODEC_CAP_DR1,
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    .long_name = NULL_IF_CONFIG_SMALL("QuickTime video (RPZA)"),
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};