GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/rl2.c Lines: 75 85 88.2 %
Date: 2020-09-25 23:16:12 Branches: 33 44 75.0 %

Line Branch Exec Source
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/*
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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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 * @file
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 * RL2 Video Decoder
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 * @author Sascha Sommer (saschasommer@freenet.de)
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 * @see 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/internal.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/mem.h"
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#include "avcodec.h"
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#include "internal.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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    uint16_t video_base;  ///< initial drawing offset
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    uint32_t clr_count;   ///< number of used colors (currently unused)
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    uint8_t *back_frame;  ///< background frame
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    uint32_t 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 output 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 uint8_t *in, int size,
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                               uint8_t *out, int stride, int video_base)
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{
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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 uint8_t *back_frame = s->back_frame;
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    const uint8_t *in_end     = in + size;
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    const uint8_t *out_end    = out + stride * s->avctx->height;
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    uint8_t *line_end;
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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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        uint8_t 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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    int ret;
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    s->avctx       = avctx;
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    avctx->pix_fmt = AV_PIX_FMT_PAL8;
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    ret = ff_set_dimensions(avctx, 320, 200);
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    if (ret < 0)
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        return ret;
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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 AVERROR(EINVAL);
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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 AVERROR_INVALIDDATA;
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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] = 0xFFU << 24 | 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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        uint8_t *back_frame = av_mallocz(avctx->width*avctx->height);
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        if (!back_frame)
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            return AVERROR(ENOMEM);
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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 *got_frame,
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                            AVPacket *avpkt)
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{
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    AVFrame *frame     = data;
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    const uint8_t *buf = avpkt->data;
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    int ret, buf_size  = avpkt->size;
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    Rl2Context *s = avctx->priv_data;
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    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
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        return ret;
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    /** run length decode */
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    rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
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                   s->video_base);
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    /** make the palette available on the way out */
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    memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
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    *got_frame = 1;
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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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    av_freep(&s->back_frame);
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    return 0;
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}
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AVCodec ff_rl2_decoder = {
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    .name           = "rl2",
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    .long_name      = NULL_IF_CONFIG_SMALL("RL2 video"),
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = AV_CODEC_ID_RL2,
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    .priv_data_size = sizeof(Rl2Context),
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    .init           = rl2_decode_init,
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    .close          = rl2_decode_end,
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    .decode         = rl2_decode_frame,
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    .capabilities   = AV_CODEC_CAP_DR1,
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};