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* MPEG1/2 common code
* Copyright (c) 2007 Aurelien Jacobs <>
* This file is part of FFmpeg.
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#ifndef AVCODEC_MPEG12_H
#define AVCODEC_MPEG12_H
#include "mpegvideo.h"
#define DC_VLC_BITS 9
#define TEX_VLC_BITS 9
extern VLC ff_dc_lum_vlc;
extern VLC ff_dc_chroma_vlc;
typedef struct Mpeg1Context {
MpegEncContext mpeg_enc_ctx;
int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
int repeat_field; /* true if we must repeat the field */
AVPanScan pan_scan; /**< some temporary storage for the panscan */
int slice_count;
int swap_uv;//indicate VCR2
int save_aspect_info;
int save_width, save_height, save_progressive_seq;
AVRational frame_rate_ext; ///< MPEG-2 specific framerate modificator
int sync; ///< Did we reach a sync point like a GOP/SEQ/KEYFrame?
int tmpgexs;
int parsed_extra;
} Mpeg1Context;
extern uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
void ff_mpeg12_common_init(MpegEncContext *s);
void ff_mpeg12_init_vlcs(void);
static inline int decode_dc(GetBitContext *gb, int component)
int code, diff;
if (component == 0) {
code = get_vlc2(gb, ff_dc_lum_vlc.table, DC_VLC_BITS, 2);
} else {
code = get_vlc2(gb, ff_dc_chroma_vlc.table, DC_VLC_BITS, 2);
if (code < 0){
av_log(NULL, AV_LOG_ERROR, "invalid dc code at\n");
return 0xffff;
if (code == 0) {
diff = 0;
} else {
diff = get_xbits(gb, code);
return diff;
extern int ff_mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n);
#endif /* AVCODEC_MPEG12_H */
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