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![Mike Melanson](/assets/img/avatar_default.png)
Konstantin Shishkov Originally committed as revision 4099 to svn://svn.ffmpeg.org/ffmpeg/trunk
175 lines
5.2 KiB
C
175 lines
5.2 KiB
C
/*
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* Autodesc RLE Decoder
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* Copyright (C) 2005 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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* @file aasc.c
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* Autodesc RLE Video Decoder by Konstantin Shishkov
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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 "common.h"
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#include "avcodec.h"
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#include "dsputil.h"
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typedef struct AascContext {
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AVCodecContext *avctx;
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AVFrame frame;
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} AascContext;
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#define FETCH_NEXT_STREAM_BYTE() \
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if (stream_ptr >= buf_size) \
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{ \
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av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (fetch)\n"); \
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break; \
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} \
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stream_byte = buf[stream_ptr++];
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static int aasc_decode_init(AVCodecContext *avctx)
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{
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AascContext *s = (AascContext *)avctx->priv_data;
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s->avctx = avctx;
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avctx->pix_fmt = PIX_FMT_BGR24;
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avctx->has_b_frames = 0;
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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 aasc_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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{
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AascContext *s = (AascContext *)avctx->priv_data;
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int stream_ptr = 4;
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unsigned char rle_code;
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unsigned char stream_byte;
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int pixel_ptr = 0;
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int row_dec, row_ptr;
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int frame_size;
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int i;
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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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row_dec = s->frame.linesize[0];
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row_ptr = (s->avctx->height - 1) * row_dec;
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frame_size = row_dec * s->avctx->height;
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while (row_ptr >= 0) {
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FETCH_NEXT_STREAM_BYTE();
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rle_code = stream_byte;
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if (rle_code == 0) {
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/* fetch the next byte to see how to handle escape code */
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FETCH_NEXT_STREAM_BYTE();
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if (stream_byte == 0) {
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/* line is done, goto the next one */
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row_ptr -= row_dec;
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pixel_ptr = 0;
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} else if (stream_byte == 1) {
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/* decode is done */
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break;
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} else if (stream_byte == 2) {
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/* reposition frame decode coordinates */
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FETCH_NEXT_STREAM_BYTE();
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pixel_ptr += stream_byte;
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FETCH_NEXT_STREAM_BYTE();
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row_ptr -= stream_byte * row_dec;
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} else {
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/* copy pixels from encoded stream */
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if ((pixel_ptr + stream_byte > avctx->width * 3) ||
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(row_ptr < 0)) {
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av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (copy1)\n");
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break;
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}
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rle_code = stream_byte;
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if (stream_ptr + rle_code > buf_size) {
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av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (copy2)\n");
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break;
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}
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for (i = 0; i < rle_code; i++) {
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FETCH_NEXT_STREAM_BYTE();
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s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
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pixel_ptr++;
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}
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if (rle_code & 1)
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stream_ptr++;
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}
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} else {
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/* decode a run of data */
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if ((pixel_ptr + rle_code > avctx->width * 3) ||
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(row_ptr < 0)) {
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av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (run1)\n");
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break;
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}
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FETCH_NEXT_STREAM_BYTE();
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while(rle_code--) {
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s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
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pixel_ptr++;
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}
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}
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}
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/* one last sanity check on the way out */
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if (stream_ptr < buf_size)
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av_log(s->avctx, AV_LOG_ERROR, " AASC: ended frame decode with bytes left over (%d < %d)\n",
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stream_ptr, buf_size);
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*data_size = sizeof(AVFrame);
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*(AVFrame*)data = s->frame;
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/* report that the buffer was completely consumed */
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return buf_size;
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}
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static int aasc_decode_end(AVCodecContext *avctx)
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{
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AascContext *s = (AascContext *)avctx->priv_data;
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/* release the last frame */
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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 aasc_decoder = {
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"aasc",
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CODEC_TYPE_VIDEO,
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CODEC_ID_AASC,
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sizeof(AascContext),
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aasc_decode_init,
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NULL,
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aasc_decode_end,
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aasc_decode_frame,
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CODEC_CAP_DR1,
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};
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