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![Thilo Borgmann](/assets/img/avatar_default.png)
These functions are not documented for other decoders and should be obvious enough even without Doxygen. patch by Thilo Borgmann, thilo.borgmann googlemail com Originally committed as revision 24237 to svn://svn.ffmpeg.org/ffmpeg/trunk
235 lines
6.3 KiB
C
235 lines
6.3 KiB
C
/*
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* RL2 Video Decoder
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* Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de)
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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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/**
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* RL2 Video Decoder
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* @file
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* @author Sascha Sommer (saschasommer@freenet.de)
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* For more information about the RL2 format, visit:
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* http://wiki.multimedia.cx/index.php?title=RL2
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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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#define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
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typedef struct Rl2Context {
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AVCodecContext *avctx;
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AVFrame frame;
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unsigned short video_base; ///< initial drawing offset
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unsigned int clr_count; ///< number of used colors (currently unused)
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unsigned char* back_frame; ///< background frame
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unsigned int palette[AVPALETTE_COUNT];
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} Rl2Context;
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/**
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* Run Length Decode a single 320x200 frame
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* @param s rl2 context
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* @param in input buffer
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* @param size input buffer size
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* @param out ouput buffer
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* @param stride stride of the output buffer
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* @param video_base offset of the rle data inside the frame
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*/
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static void rl2_rle_decode(Rl2Context *s,const unsigned char* in,int size,
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unsigned char* out,int stride,int video_base){
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int base_x = video_base % s->avctx->width;
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int base_y = video_base / s->avctx->width;
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int stride_adj = stride - s->avctx->width;
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int i;
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const unsigned char* back_frame = s->back_frame;
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const unsigned char* in_end = in + size;
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const unsigned char* out_end = out + stride * s->avctx->height;
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unsigned char* line_end = out + s->avctx->width;
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/** copy start of the background frame */
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for(i=0;i<=base_y;i++){
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if(s->back_frame)
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memcpy(out,back_frame,s->avctx->width);
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out += stride;
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back_frame += s->avctx->width;
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}
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back_frame += base_x - s->avctx->width;
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line_end = out - stride_adj;
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out += base_x - stride;
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/** decode the variable part of the frame */
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while(in < in_end){
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unsigned char val = *in++;
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int len = 1;
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if(val >= 0x80){
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if(in >= in_end)
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break;
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len = *in++;
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if(!len)
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break;
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}
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if(len >= out_end - out)
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break;
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if(s->back_frame)
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val |= 0x80;
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else
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val &= ~0x80;
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while(len--){
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*out++ = (val == 0x80)? *back_frame:val;
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back_frame++;
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if(out == line_end){
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out += stride_adj;
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line_end += stride;
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if(len >= out_end - out)
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break;
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}
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}
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}
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/** copy the rest from the background frame */
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if(s->back_frame){
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while(out < out_end){
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memcpy(out, back_frame, line_end - out);
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back_frame += line_end - out;
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out = line_end + stride_adj;
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line_end += stride;
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}
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}
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}
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/**
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* Initialize the decoder
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* @param avctx decoder context
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* @return 0 success, -1 on error
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*/
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static av_cold int rl2_decode_init(AVCodecContext *avctx)
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{
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Rl2Context *s = avctx->priv_data;
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int back_size;
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int i;
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s->avctx = avctx;
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avctx->pix_fmt = PIX_FMT_PAL8;
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/** parse extra data */
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if(!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE){
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av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
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return -1;
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}
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/** get frame_offset */
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s->video_base = AV_RL16(&avctx->extradata[0]);
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s->clr_count = AV_RL32(&avctx->extradata[2]);
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if(s->video_base >= avctx->width * avctx->height){
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av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
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return -1;
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}
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/** initialize palette */
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for(i=0;i<AVPALETTE_COUNT;i++)
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s->palette[i] = AV_RB24(&avctx->extradata[6 + i * 3]);
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/** decode background frame if present */
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back_size = avctx->extradata_size - EXTRADATA1_SIZE;
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if(back_size > 0){
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unsigned char* back_frame = av_mallocz(avctx->width*avctx->height);
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if(!back_frame)
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return -1;
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rl2_rle_decode(s,avctx->extradata + EXTRADATA1_SIZE,back_size,
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back_frame,avctx->width,0);
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s->back_frame = back_frame;
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}
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return 0;
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}
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static int rl2_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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Rl2Context *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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/** get buffer */
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s->frame.reference= 0;
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if(avctx->get_buffer(avctx, &s->frame)) {
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av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return -1;
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}
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/** run length decode */
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rl2_rle_decode(s,buf,buf_size,s->frame.data[0],s->frame.linesize[0],s->video_base);
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/** make the palette available on the way out */
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memcpy(s->frame.data[1], s->palette, AVPALETTE_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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/**
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* Uninit decoder
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* @param avctx decoder context
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* @return 0 success, -1 on error
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*/
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static av_cold int rl2_decode_end(AVCodecContext *avctx)
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{
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Rl2Context *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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av_free(s->back_frame);
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return 0;
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}
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AVCodec rl2_decoder = {
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"rl2",
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AVMEDIA_TYPE_VIDEO,
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CODEC_ID_RL2,
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sizeof(Rl2Context),
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rl2_decode_init,
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NULL,
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rl2_decode_end,
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rl2_decode_frame,
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CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
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};
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