FFmpeg/libavcodec/huffman.c
Michael Niedermayer 6cb2085278 Merge remote-tracking branch 'qatar/master'
* qatar/master: (27 commits)
  ppc: Add ff_ prefix to nonstatic symbols
  sh4: Add ff_ prefix to nonstatic symbols
  mpegvideo: Add ff_ prefix to nonstatic functions
  rtjpeg: Add ff_ prefix to nonstatic symbols
  rv: Add ff_ prefix to nonstatic symbols
  vp56: Add ff_ prefix to nonstatic symbols
  vorbis: Add ff_ prefix to nonstatic symbols
  msmpeg4: Add ff_ prefix to nonstatic symbols
  vc1: Add ff_ prefix to nonstatic symbols
  msmpeg4: Add ff_ prefixes to nonstatic symbols
  snow: Add ff_ prefix to nonstatic symbols
  mpeg12: Add ff_ prefix to nonstatic symbols
  mpeg4: Add ff_ prefixes to nonstatic symbols
  lagarith: Add ff_ prefix to lag_rac_init
  libavcodec: Add ff_ prefix to j_rev_dct*
  dsputil: Add ff_ prefix to inv_zigzag_direct16
  libavcodec: Prefix fdct_ifast, fdct_ifast248
  dsputil: Add ff_ prefix to the dsputil*_init* functions
  libavcodec: Add ff_ prefix to some nonstatic symbols
  vlc/rl: Add ff_ prefix to the nonstatic symbols
  ...

Conflicts:
	libavcodec/Makefile
	libavcodec/allcodecs.c
	libavcodec/dnxhddec.c
	libavcodec/ffv1.c
	libavcodec/h263.h
	libavcodec/h263dec.c
	libavcodec/h264.c
	libavcodec/mpegvideo.c
	libavcodec/mpegvideo_enc.c
	libavcodec/nuv.c
	libavcodec/ppc/dsputil_ppc.c
	libavcodec/proresdsp.c
	libavcodec/svq3.c
	libavcodec/version.h
	libavformat/dv.h
	libavformat/dvenc.c
	libavformat/matroskadec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2012-02-16 01:34:37 +01:00

114 lines
3.4 KiB
C

/*
* Copyright (c) 2006 Konstantin Shishkov
*
* 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
* huffman tree builder and VLC generator
*/
#include "avcodec.h"
#include "get_bits.h"
#include "huffman.h"
/* symbol for Huffman tree node */
#define HNODE -1
static void get_tree_codes(uint32_t *bits, int16_t *lens, uint8_t *xlat, Node *nodes, int node, uint32_t pfx, int pl, int *pos, int no_zero_count)
{
int s;
s = nodes[node].sym;
if(s != HNODE || (no_zero_count && !nodes[node].count)){
bits[*pos] = pfx;
lens[*pos] = pl;
xlat[*pos] = s;
(*pos)++;
}else{
pfx <<= 1;
pl++;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0, pfx, pl, pos,
no_zero_count);
pfx |= 1;
get_tree_codes(bits, lens, xlat, nodes, nodes[node].n0+1, pfx, pl, pos,
no_zero_count);
}
}
static int build_huff_tree(VLC *vlc, Node *nodes, int head, int flags)
{
int no_zero_count = !(flags & FF_HUFFMAN_FLAG_ZERO_COUNT);
uint32_t bits[256];
int16_t lens[256];
uint8_t xlat[256];
int pos = 0;
get_tree_codes(bits, lens, xlat, nodes, head, 0, 0, &pos, no_zero_count);
return ff_init_vlc_sparse(vlc, 9, pos, lens, 2, 2, bits, 4, 4, xlat, 1, 1, 0);
}
/**
* nodes size must be 2*nb_codes
* first nb_codes nodes.count must be set
*/
int ff_huff_build_tree(AVCodecContext *avctx, VLC *vlc, int nb_codes,
Node *nodes, HuffCmp cmp, int flags)
{
int i, j;
int cur_node;
int64_t sum = 0;
for(i = 0; i < nb_codes; i++){
nodes[i].sym = i;
nodes[i].n0 = -2;
sum += nodes[i].count;
}
if(sum >> 31) {
av_log(avctx, AV_LOG_ERROR, "Too high symbol frequencies. Tree construction is not possible\n");
return -1;
}
qsort(nodes, nb_codes, sizeof(Node), cmp);
cur_node = nb_codes;
nodes[nb_codes*2-1].count = 0;
for(i = 0; i < nb_codes*2-1; i += 2){
uint32_t cur_count = nodes[i].count + nodes[i+1].count;
// find correct place to insert new node, and
// make space for the new node while at it
for(j = cur_node; j > i + 2; j--){
if(cur_count > nodes[j-1].count ||
(cur_count == nodes[j-1].count &&
!(flags & FF_HUFFMAN_FLAG_HNODE_FIRST)))
break;
nodes[j] = nodes[j - 1];
}
nodes[j].sym = HNODE;
nodes[j].count = cur_count;
nodes[j].n0 = i;
cur_node++;
}
if(build_huff_tree(vlc, nodes, nb_codes*2-2, flags) < 0){
av_log(avctx, AV_LOG_ERROR, "Error building tree\n");
return -1;
}
return 0;
}