ffmpeg/libavcodec/put_golomb.h

155 lines
3.6 KiB
C

/*
* exp golomb vlc writing stuff
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2004 Alex Beregszaszi
*
* 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
* @brief
* exp golomb vlc writing stuff
* @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
*/
#ifndef AVCODEC_PUT_GOLOMB_H
#define AVCODEC_PUT_GOLOMB_H
#include <stdint.h>
#include "put_bits.h"
extern const uint8_t ff_ue_golomb_len[256];
/**
* write unsigned exp golomb code. 2^16 - 2 at most
*/
static inline void set_ue_golomb(PutBitContext *pb, int i)
{
av_assert2(i >= 0);
av_assert2(i <= 0xFFFE);
if (i < 256)
put_bits(pb, ff_ue_golomb_len[i], i + 1);
else {
int e = av_log2(i + 1);
put_bits(pb, 2 * e + 1, i + 1);
}
}
/**
* write unsigned exp golomb code. 2^32-2 at most.
*/
static inline void set_ue_golomb_long(PutBitContext *pb, uint32_t i)
{
av_assert2(i <= (UINT32_MAX - 1));
if (i < 256)
put_bits(pb, ff_ue_golomb_len[i], i + 1);
else {
int e = av_log2(i + 1);
put_bits64(pb, 2 * e + 1, i + 1);
}
}
/**
* write truncated unsigned exp golomb code.
*/
static inline void set_te_golomb(PutBitContext *pb, int i, int range)
{
av_assert2(range >= 1);
av_assert2(i <= range);
if (range == 2)
put_bits(pb, 1, i ^ 1);
else
set_ue_golomb(pb, i);
}
/**
* write signed exp golomb code. 16 bits at most.
*/
static inline void set_se_golomb(PutBitContext *pb, int i)
{
i = 2 * i - 1;
if (i < 0)
i ^= -1; //FIXME check if gcc does the right thing
set_ue_golomb(pb, i);
}
/**
* write unsigned golomb rice code (ffv1).
*/
static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit,
int esc_len)
{
int e;
av_assert2(i >= 0);
e = i >> k;
if (e < limit)
put_bits(pb, e + k + 1, (1 << k) + av_zero_extend(i, k));
else
put_bits(pb, limit + esc_len, i - limit + 1);
}
/**
* write unsigned golomb rice code (jpegls).
*/
static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k,
int limit, int esc_len)
{
int e;
av_assert2(i >= 0);
e = (i >> k) + 1;
if (e < limit) {
while (e > 31) {
put_bits(pb, 31, 0);
e -= 31;
}
put_bits(pb, e, 1);
if (k)
put_sbits(pb, k, i);
} else {
while (limit > 31) {
put_bits(pb, 31, 0);
limit -= 31;
}
put_bits(pb, limit, 1);
put_bits(pb, esc_len, i - 1);
}
}
/**
* write signed golomb rice code (ffv1).
*/
static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
int esc_len)
{
int v;
v = -2 * i - 1;
v ^= (v >> 31);
set_ur_golomb(pb, v, k, limit, esc_len);
}
#endif /* AVCODEC_PUT_GOLOMB_H */