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1 11e29a41 Mike Melanson
/*
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 * Quicktime Graphics (SMC) Video Decoder
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 * Copyright (C) 2003 the ffmpeg project
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 *
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 * This library 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 of the License, or (at your option) any later version.
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 *
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 * This library 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 this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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/**
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 * @file smc.c
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 * QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)
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 * For more information about the SMC format, visit:
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 *   http://www.pcisys.net/~melanson/codecs/
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 *
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 * The SMC decoder outputs PAL8 colorspace data.
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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 <unistd.h>
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#include "common.h"
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#include "avcodec.h"
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#include "dsputil.h"
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39 d705e4a6 Michael Niedermayer
#define printf(...) {} //(f)printf() usage is forbidden in libavcodec, use av_log
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#define fprintf(...) {} 
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42 11e29a41 Mike Melanson
#define CPAIR 2
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#define CQUAD 4
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#define COCTET 8
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#define COLORS_PER_TABLE 256
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typedef struct SmcContext {
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    AVCodecContext *avctx;
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    DSPContext dsp;
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    AVFrame frame;
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    unsigned char *buf;
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    int size;
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    /* SMC color tables */
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    unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
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    unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
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    unsigned char color_octets[COLORS_PER_TABLE * COCTET];
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} SmcContext;
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#define GET_BLOCK_COUNT() \
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  (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);
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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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        printf("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 smc_decode_stream(SmcContext *s)
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{
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    int width = s->avctx->width;
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    int height = s->avctx->height;
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    int stride = s->frame.linesize[0];
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    int i;
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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 int color_flags;
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    unsigned int color_flags_a;
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    unsigned int color_flags_b;
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    unsigned int flag_mask;
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    unsigned char *pixels = s->frame.data[0];
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    int image_size = height * s->frame.linesize[0];
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    int row_ptr = 0;
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    int pixel_ptr = 0;
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    int pixel_x, pixel_y;
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    int row_inc = stride - 4;
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    int block_ptr;
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    int prev_block_ptr;
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    int prev_block_ptr1, prev_block_ptr2;
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    int prev_block_flag;
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    int total_blocks;
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    int color_table_index;  /* indexes to color pair, quad, or octet tables */
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    int pixel;
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    int color_pair_index = 0;
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    int color_quad_index = 0;
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    int color_octet_index = 0;
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    /* make the palette available */
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    memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
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    if (s->avctx->palctrl->palette_changed) {
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        s->frame.palette_has_changed = 1;
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        s->avctx->palctrl->palette_changed = 0;
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    }
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    chunk_size = BE_32(&s->buf[stream_ptr]) & 0x00FFFFFF;
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    stream_ptr += 4;
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    if (chunk_size != s->size)
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        printf("warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
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            chunk_size, s->size);
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    chunk_size = s->size;
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    total_blocks = (s->avctx->width * s->avctx->height) / (4 * 4);
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    /* traverse through the blocks */
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    while (total_blocks) {
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        /* sanity checks */
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        /* make sure stream ptr hasn't gone out of bounds */
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        if (stream_ptr > chunk_size) {
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            printf("SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
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                stream_ptr, chunk_size);
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            return;
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        }
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        /* make sure the row pointer hasn't gone wild */
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        if (row_ptr >= image_size) {
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            printf("SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
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                row_ptr, image_size);
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            return;
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        }
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        opcode = s->buf[stream_ptr++];
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        switch (opcode & 0xF0) {
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        /* skip n blocks */
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        case 0x00:
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        case 0x10:
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            n_blocks = GET_BLOCK_COUNT();
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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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        /* repeat last block n times */
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        case 0x20:
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        case 0x30:
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            n_blocks = GET_BLOCK_COUNT();
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            /* sanity check */
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            if ((row_ptr == 0) && (pixel_ptr == 0)) {
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                printf("encountered repeat block opcode (%02X) but no blocks rendered yet\n",
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                    opcode & 0xF0);
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                break;
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            }
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            /* figure out where the previous block started */
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            if (pixel_ptr == 0)
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                prev_block_ptr1 = 
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                    (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;
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            else
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                prev_block_ptr1 = row_ptr + pixel_ptr - 4;
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            while (n_blocks--) {
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                block_ptr = row_ptr + pixel_ptr;
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                prev_block_ptr = prev_block_ptr1;
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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++] = pixels[prev_block_ptr++];
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                    }
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                    block_ptr += row_inc;
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                    prev_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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        /* repeat previous pair of blocks n times */
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        case 0x40:
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        case 0x50:
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            n_blocks = GET_BLOCK_COUNT();
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            n_blocks *= 2;
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            /* sanity check */
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            if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {
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                printf("encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
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                    opcode & 0xF0);
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                break;
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            }
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            /* figure out where the previous 2 blocks started */
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            if (pixel_ptr == 0)
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                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + 
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                    s->avctx->width - 4 * 2;
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            else if (pixel_ptr == 4)
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                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
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            else
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                prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;
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            if (pixel_ptr == 0)
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                prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
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            else
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                prev_block_ptr2 = row_ptr + pixel_ptr - 4;
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            prev_block_flag = 0;
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            while (n_blocks--) {
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                block_ptr = row_ptr + pixel_ptr;
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                if (prev_block_flag)
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                    prev_block_ptr = prev_block_ptr2;
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                else
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                    prev_block_ptr = prev_block_ptr1;
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                prev_block_flag = !prev_block_flag;
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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++] = pixels[prev_block_ptr++];
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                    }
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                    block_ptr += row_inc;
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                    prev_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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        /* 1-color block encoding */
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        case 0x60:
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        case 0x70:
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            n_blocks = GET_BLOCK_COUNT();
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            pixel = s->buf[stream_ptr++];
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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++] = pixel;
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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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        /* 2-color block encoding */
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        case 0x80:
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        case 0x90:
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            n_blocks = (opcode & 0x0F) + 1;
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            /* figure out which color pair to use to paint the 2-color block */
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            if ((opcode & 0xF0) == 0x80) {
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                /* fetch the next 2 colors from bytestream and store in next
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                 * available entry in the color pair table */
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                for (i = 0; i < CPAIR; i++) {
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                    pixel = s->buf[stream_ptr++];
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                    color_table_index = CPAIR * color_pair_index + i;
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                    s->color_pairs[color_table_index] = pixel;
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                }
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                /* this is the base index to use for this block */
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                color_table_index = CPAIR * color_pair_index;
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                color_pair_index++;
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                /* wraparound */
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                if (color_pair_index == COLORS_PER_TABLE)
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                    color_pair_index = 0;
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            } else
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                color_table_index = CPAIR * s->buf[stream_ptr++];
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            while (n_blocks--) {
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                color_flags = BE_16(&s->buf[stream_ptr]);
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                stream_ptr += 2;
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                flag_mask = 0x8000;
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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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                        if (color_flags & flag_mask)
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                            pixel = color_table_index + 1;
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                        else
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                            pixel = color_table_index;
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                        flag_mask >>= 1;
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                        pixels[block_ptr++] = s->color_pairs[pixel];
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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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        /* 4-color block encoding */
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        case 0xA0:
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        case 0xB0:
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            n_blocks = (opcode & 0x0F) + 1;
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            /* figure out which color quad to use to paint the 4-color block */
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            if ((opcode & 0xF0) == 0xA0) {
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                /* fetch the next 4 colors from bytestream and store in next
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                 * available entry in the color quad table */
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                for (i = 0; i < CQUAD; i++) {
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                    pixel = s->buf[stream_ptr++];
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                    color_table_index = CQUAD * color_quad_index + i;
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                    s->color_quads[color_table_index] = pixel;
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                }
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                /* this is the base index to use for this block */
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                color_table_index = CQUAD * color_quad_index;
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                color_quad_index++;
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                /* wraparound */
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                if (color_quad_index == COLORS_PER_TABLE)
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                    color_quad_index = 0;
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            } else
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                color_table_index = CQUAD * s->buf[stream_ptr++];
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            while (n_blocks--) {
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                color_flags = BE_32(&s->buf[stream_ptr]);
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                stream_ptr += 4;
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                /* flag mask actually acts as a bit shift count here */
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                flag_mask = 30;
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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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                        pixel = color_table_index + 
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                            ((color_flags >> flag_mask) & 0x03);
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                        flag_mask -= 2;
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                        pixels[block_ptr++] = s->color_quads[pixel];
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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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        /* 8-color block encoding */
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        case 0xC0:
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        case 0xD0:
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            n_blocks = (opcode & 0x0F) + 1;
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            /* figure out which color octet to use to paint the 8-color block */
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            if ((opcode & 0xF0) == 0xC0) {
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                /* fetch the next 8 colors from bytestream and store in next
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                 * available entry in the color octet table */
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                for (i = 0; i < COCTET; i++) {
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                    pixel = s->buf[stream_ptr++];
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                    color_table_index = COCTET * color_octet_index + i;
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                    s->color_octets[color_table_index] = pixel;
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                }
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                /* this is the base index to use for this block */
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                color_table_index = COCTET * color_octet_index;
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                color_octet_index++;
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                /* wraparound */
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                if (color_octet_index == COLORS_PER_TABLE)
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                    color_octet_index = 0;
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            } else
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                color_table_index = COCTET * s->buf[stream_ptr++];
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            while (n_blocks--) {
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                /*
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                  For this input of 6 hex bytes:
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                    01 23 45 67 89 AB
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                  Mangle it to this output:
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                    flags_a = xx012456, flags_b = xx89A37B
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                */
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                /* build the color flags */
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                color_flags_a = color_flags_b = 0;
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                color_flags_a =
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                    (s->buf[stream_ptr + 0] << 16) |
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                    ((s->buf[stream_ptr + 1] & 0xF0) << 8) |
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                    ((s->buf[stream_ptr + 2] & 0xF0) << 4) |
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                    ((s->buf[stream_ptr + 2] & 0x0F) << 4) |
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                    ((s->buf[stream_ptr + 3] & 0xF0) >> 4);
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                color_flags_b =
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                    (s->buf[stream_ptr + 4] << 16) |
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                    ((s->buf[stream_ptr + 5] & 0xF0) << 8) |
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                    ((s->buf[stream_ptr + 1] & 0x0F) << 8) |
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                    ((s->buf[stream_ptr + 3] & 0x0F) << 4) |
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                    (s->buf[stream_ptr + 5] & 0x0F);
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                stream_ptr += 6;
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                color_flags = color_flags_a;
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                /* flag mask actually acts as a bit shift count here */
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                flag_mask = 21;
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                block_ptr = row_ptr + pixel_ptr;
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                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
394
                    /* reload flags at third row (iteration pixel_y == 2) */
395
                    if (pixel_y == 2) {
396
                        color_flags = color_flags_b;
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                        flag_mask = 21;
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                    }
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                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
400
                        pixel = color_table_index + 
401
                            ((color_flags >> flag_mask) & 0x07);
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                        flag_mask -= 3;
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                        pixels[block_ptr++] = s->color_octets[pixel];
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                    }
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                    block_ptr += row_inc;
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                }
407
                ADVANCE_BLOCK();
408
            }
409
            break;
410
411
        /* 16-color block encoding (every pixel is a different color) */
412
        case 0xE0:
413
            n_blocks = (opcode & 0x0F) + 1;
414
415
            while (n_blocks--) {
416
                block_ptr = row_ptr + pixel_ptr;
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                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
418
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
419
                        pixels[block_ptr++] = s->buf[stream_ptr++];
420
                    }
421
                    block_ptr += row_inc;
422
                }
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                ADVANCE_BLOCK();
424
            }
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            break;
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        case 0xF0:
428
            printf("0xF0 opcode seen in SMC chunk (xine developers would like to know)\n");
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            break;
430
        }
431
    }
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}
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static int smc_decode_init(AVCodecContext *avctx)
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{
436
    SmcContext *s = (SmcContext *)avctx->priv_data;
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    s->avctx = avctx;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    avctx->has_b_frames = 0;
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    dsputil_init(&s->dsp, avctx);
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443 e1c2a5a0 Roberto Togni
    s->frame.data[0] = NULL;
444 11e29a41 Mike Melanson
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    return 0;
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}
447
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static int smc_decode_frame(AVCodecContext *avctx,
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                             void *data, int *data_size,
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                             uint8_t *buf, int buf_size)
451
{
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    SmcContext *s = (SmcContext *)avctx->priv_data;
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454 155aa417 Mike Melanson
    /* no supplementary picture */
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    if (buf_size == 0)
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        return 0;
457 e1c2a5a0 Roberto Togni
458 11e29a41 Mike Melanson
    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 | 
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                            FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
464 e1c2a5a0 Roberto Togni
    if (avctx->reget_buffer(avctx, &s->frame)) {
465
        printf ("reget_buffer() failed\n");
466 11e29a41 Mike Melanson
        return -1;
467
    }
468
469
    smc_decode_stream(s);
470
471
    *data_size = sizeof(AVFrame);
472
    *(AVFrame*)data = s->frame;
473
474
    /* always report that the buffer was completely consumed */
475
    return buf_size;
476
}
477
478
static int smc_decode_end(AVCodecContext *avctx)
479
{
480
    SmcContext *s = (SmcContext *)avctx->priv_data;
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482 e1c2a5a0 Roberto Togni
    if (s->frame.data[0])
483
        avctx->release_buffer(avctx, &s->frame);
484 11e29a41 Mike Melanson
485
    return 0;
486
}
487
488
AVCodec smc_decoder = {
489
    "smc",
490
    CODEC_TYPE_VIDEO,
491
    CODEC_ID_SMC,
492
    sizeof(SmcContext),
493
    smc_decode_init,
494
    NULL,
495
    smc_decode_end,
496
    smc_decode_frame,
497
    CODEC_CAP_DR1,
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};