From b613bacca9c256f1483c46847f713e47a0e9a5f6 Mon Sep 17 00:00:00 2001 From: Loren Merritt Date: Thu, 24 May 2007 17:38:56 +0000 Subject: [PATCH] add init_vlc_sparse(). faster than init_vlc() if there are lots of holes in the tables. Originally committed as revision 9117 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/bitstream.c | 18 ++++++++++++++---- libavcodec/bitstream.h | 12 +++++++++++- 2 files changed, 25 insertions(+), 5 deletions(-) diff --git a/libavcodec/bitstream.c b/libavcodec/bitstream.c index 41ab370aad..cb80376093 100644 --- a/libavcodec/bitstream.c +++ b/libavcodec/bitstream.c @@ -104,9 +104,10 @@ static int build_table(VLC *vlc, int table_nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, + const void *symbols, int symbols_wrap, int symbols_size, uint32_t code_prefix, int n_prefix, int flags) { - int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2; + int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol; uint32_t code; VLC_TYPE (*table)[2]; @@ -132,6 +133,10 @@ static int build_table(VLC *vlc, int table_nb_bits, /* we accept tables with holes */ if (n <= 0) continue; + if (!symbols) + symbol = i; + else + GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size); #if defined(DEBUG_VLC) && 0 av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code); #endif @@ -158,7 +163,7 @@ static int build_table(VLC *vlc, int table_nb_bits, return -1; } table[j][1] = n; //bits - table[j][0] = i; //code + table[j][0] = symbol; j++; } } else { @@ -189,6 +194,7 @@ static int build_table(VLC *vlc, int table_nb_bits, index = build_table(vlc, n, nb_codes, bits, bits_wrap, bits_size, codes, codes_wrap, codes_size, + symbols, symbols_wrap, symbols_size, (flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i), n_prefix + table_nb_bits, flags); if (index < 0) @@ -214,6 +220,8 @@ static int build_table(VLC *vlc, int table_nb_bits, 'codes' : table which gives the bit pattern of of each vlc code. + 'symbols' : table which gives the values to be returned from get_vlc(). + 'xxx_wrap' : give the number of bytes between each entry of the 'bits' or 'codes' tables. @@ -221,14 +229,15 @@ static int build_table(VLC *vlc, int table_nb_bits, or 'codes' tables. 'wrap' and 'size' allows to use any memory configuration and types - (byte/word/long) to store the 'bits' and 'codes' tables. + (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables. 'use_static' should be set to 1 for tables, which should be freed with av_free_static(), 0 if free_vlc() will be used. */ -int init_vlc(VLC *vlc, int nb_bits, int nb_codes, +int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, + const void *symbols, int symbols_wrap, int symbols_size, int flags) { vlc->bits = nb_bits; @@ -250,6 +259,7 @@ int init_vlc(VLC *vlc, int nb_bits, int nb_codes, if (build_table(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size, codes, codes_wrap, codes_size, + symbols, symbols_wrap, symbols_size, 0, 0, flags) < 0) { av_free(vlc->table); return -1; diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h index 2ef76ec5d7..e30ba83510 100644 --- a/libavcodec/bitstream.h +++ b/libavcodec/bitstream.h @@ -799,9 +799,19 @@ static inline void align_get_bits(GetBitContext *s) if(n) skip_bits(s, n); } -int init_vlc(VLC *vlc, int nb_bits, int nb_codes, +#define init_vlc(vlc, nb_bits, nb_codes,\ + bits, bits_wrap, bits_size,\ + codes, codes_wrap, codes_size,\ + flags)\ + init_vlc_sparse(vlc, nb_bits, nb_codes,\ + bits, bits_wrap, bits_size,\ + codes, codes_wrap, codes_size,\ + NULL, 0, 0, flags) + +int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, + const void *symbols, int symbols_wrap, int symbols_size, int flags); #define INIT_VLC_USE_STATIC 1 #define INIT_VLC_LE 2