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![Diego Biurrun](/assets/img/avatar_default.png)
The prefix is a historic remnant that probably meant "alternative". Now that the A32 bitstream reader has been dropped it makes no sense anymore.
244 lines
7.3 KiB
C
244 lines
7.3 KiB
C
/*
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* Intel Indeo 2 codec
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* Copyright (c) 2005 Konstantin Shishkov
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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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* Intel Indeo 2 decoder.
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*/
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#define BITSTREAM_READER_LE
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#include "avcodec.h"
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#include "get_bits.h"
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#include "indeo2data.h"
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#include "libavutil/common.h"
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typedef struct Ir2Context{
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AVCodecContext *avctx;
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AVFrame picture;
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GetBitContext gb;
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int decode_delta;
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} Ir2Context;
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#define CODE_VLC_BITS 14
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static VLC ir2_vlc;
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/* Indeo 2 codes are in range 0x01..0x7F and 0x81..0x90 */
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static inline int ir2_get_code(GetBitContext *gb)
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{
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return get_vlc2(gb, ir2_vlc.table, CODE_VLC_BITS, 1) + 1;
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}
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static int ir2_decode_plane(Ir2Context *ctx, int width, int height, uint8_t *dst, int stride,
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const uint8_t *table)
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{
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int i;
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int j;
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int out = 0;
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int c;
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int t;
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if(width&1)
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return -1;
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/* first line contain absolute values, other lines contain deltas */
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while (out < width){
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c = ir2_get_code(&ctx->gb);
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if(c >= 0x80) { /* we have a run */
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c -= 0x7F;
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if(out + c*2 > width)
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return -1;
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for (i = 0; i < c * 2; i++)
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dst[out++] = 0x80;
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} else { /* copy two values from table */
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dst[out++] = table[c * 2];
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dst[out++] = table[(c * 2) + 1];
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}
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}
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dst += stride;
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for (j = 1; j < height; j++){
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out = 0;
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while (out < width){
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c = ir2_get_code(&ctx->gb);
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if(c >= 0x80) { /* we have a skip */
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c -= 0x7F;
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if(out + c*2 > width)
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return -1;
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for (i = 0; i < c * 2; i++) {
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dst[out] = dst[out - stride];
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out++;
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}
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} else { /* add two deltas from table */
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t = dst[out - stride] + (table[c * 2] - 128);
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t= av_clip_uint8(t);
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dst[out] = t;
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out++;
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t = dst[out - stride] + (table[(c * 2) + 1] - 128);
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t= av_clip_uint8(t);
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dst[out] = t;
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out++;
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}
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}
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dst += stride;
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}
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return 0;
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}
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static int ir2_decode_plane_inter(Ir2Context *ctx, int width, int height, uint8_t *dst, int stride,
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const uint8_t *table)
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{
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int j;
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int out = 0;
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int c;
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int t;
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if(width&1)
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return -1;
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for (j = 0; j < height; j++){
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out = 0;
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while (out < width){
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c = ir2_get_code(&ctx->gb);
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if(c >= 0x80) { /* we have a skip */
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c -= 0x7F;
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out += c * 2;
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} else { /* add two deltas from table */
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t = dst[out] + (((table[c * 2] - 128)*3) >> 2);
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t= av_clip_uint8(t);
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dst[out] = t;
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out++;
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t = dst[out] + (((table[(c * 2) + 1] - 128)*3) >> 2);
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t= av_clip_uint8(t);
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dst[out] = t;
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out++;
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}
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}
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dst += stride;
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}
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return 0;
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}
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static int ir2_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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Ir2Context * const s = avctx->priv_data;
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AVFrame *picture = data;
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AVFrame * const p= (AVFrame*)&s->picture;
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int start;
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if(p->data[0])
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avctx->release_buffer(avctx, p);
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p->reference = 1;
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p->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
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if (avctx->reget_buffer(avctx, p)) {
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av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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return -1;
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}
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start = 48; /* hardcoded for now */
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if (start >= buf_size) {
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av_log(s->avctx, AV_LOG_ERROR, "input buffer size too small (%d)\n", buf_size);
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return AVERROR_INVALIDDATA;
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}
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s->decode_delta = buf[18];
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/* decide whether frame uses deltas or not */
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#ifndef BITSTREAM_READER_LE
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for (i = 0; i < buf_size; i++)
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buf[i] = av_reverse[buf[i]];
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#endif
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init_get_bits(&s->gb, buf + start, (buf_size - start) * 8);
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if (s->decode_delta) { /* intraframe */
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ir2_decode_plane(s, avctx->width, avctx->height,
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s->picture.data[0], s->picture.linesize[0], ir2_luma_table);
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/* swapped U and V */
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ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,
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s->picture.data[2], s->picture.linesize[2], ir2_luma_table);
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ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,
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s->picture.data[1], s->picture.linesize[1], ir2_luma_table);
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} else { /* interframe */
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ir2_decode_plane_inter(s, avctx->width, avctx->height,
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s->picture.data[0], s->picture.linesize[0], ir2_luma_table);
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/* swapped U and V */
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ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,
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s->picture.data[2], s->picture.linesize[2], ir2_luma_table);
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ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,
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s->picture.data[1], s->picture.linesize[1], ir2_luma_table);
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}
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*picture= *(AVFrame*)&s->picture;
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*data_size = sizeof(AVPicture);
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return buf_size;
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}
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static av_cold int ir2_decode_init(AVCodecContext *avctx){
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Ir2Context * const ic = avctx->priv_data;
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static VLC_TYPE vlc_tables[1 << CODE_VLC_BITS][2];
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ic->avctx = avctx;
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avctx->pix_fmt= PIX_FMT_YUV410P;
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ir2_vlc.table = vlc_tables;
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ir2_vlc.table_allocated = 1 << CODE_VLC_BITS;
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#ifdef BITSTREAM_READER_LE
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init_vlc(&ir2_vlc, CODE_VLC_BITS, IR2_CODES,
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&ir2_codes[0][1], 4, 2,
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&ir2_codes[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);
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#else
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init_vlc(&ir2_vlc, CODE_VLC_BITS, IR2_CODES,
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&ir2_codes[0][1], 4, 2,
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&ir2_codes[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
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#endif
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return 0;
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}
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static av_cold int ir2_decode_end(AVCodecContext *avctx){
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Ir2Context * const ic = avctx->priv_data;
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AVFrame *pic = &ic->picture;
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if (pic->data[0])
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avctx->release_buffer(avctx, pic);
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return 0;
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}
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AVCodec ff_indeo2_decoder = {
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.name = "indeo2",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = CODEC_ID_INDEO2,
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.priv_data_size = sizeof(Ir2Context),
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.init = ir2_decode_init,
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.close = ir2_decode_end,
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.decode = ir2_decode_frame,
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.capabilities = CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("Intel Indeo 2"),
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};
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