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FFmpeg/libavcodec/mpeg12vlc.h
Andreas Rheinhardt c4990409f2 avcodec/mpeg12: Reduce size of motion-vector VLC
It currently uses 9 bits per table, but there are no codes with
nine bits at all, while there are codes with eight, ten and eleven bits.
So reducing the table size to eight bits will not reduce the amount of
codes that can be parsed in the first step, but it allows to reduce the
size of the motion-vector VLC.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-10-12 02:00:08 +02:00

53 lines
1.4 KiB
C

/*
* MPEG-1/2 VLC
* copyright (c) 2000,2001 Fabrice Bellard
* copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* 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
*/
/**
* @file
* MPEG-1/2 VLC.
*/
#ifndef AVCODEC_MPEG12VLC_H
#define AVCODEC_MPEG12VLC_H
#include "vlc.h"
#define DC_VLC_BITS 9
#define MV_VLC_BITS 8
#define TEX_VLC_BITS 9
#define MBINCR_VLC_BITS 9
#define MB_PAT_VLC_BITS 9
#define MB_PTYPE_VLC_BITS 6
#define MB_BTYPE_VLC_BITS 6
extern VLC ff_dc_lum_vlc;
extern VLC ff_dc_chroma_vlc;
extern VLC ff_mbincr_vlc;
extern VLC ff_mb_ptype_vlc;
extern VLC ff_mb_btype_vlc;
extern VLC ff_mb_pat_vlc;
extern VLC ff_mv_vlc;
void ff_mpeg12_init_vlcs(void);
#endif /* AVCODEC_MPEG12VLC_H */