diff options
| author | zhaoxiu.zeng <zhaoxiu.zeng@gmail.com> | 2015-02-25 00:28:45 +0800 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2015-02-28 15:25:03 +0100 |
| commit | ec908ce427022faa6410c70bf82835f0db636356 (patch) | |
| tree | 813b107bee2ef996920658b387a5f8e25fc6ffe3 | |
| parent | ccad34e3cae6447747ec2223cffea324123fa68a (diff) | |
avcodec/vc1_block: Optimize vc1_decode_ac_coeff()
Avoid branches in sign handling
Move local variables to where they are used
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
| -rw-r--r-- | libavcodec/vc1_block.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index 05361baa03..71b0b4d997 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -487,17 +487,16 @@ static void vc1_decode_ac_coeff(VC1Context *v, int *last, int *skip, int *value, int codingset) { GetBitContext *gb = &v->s.gb; - int index, escape, run = 0, level = 0, lst = 0; + int index, run, level, lst, sign; index = get_vlc2(gb, ff_vc1_ac_coeff_table[codingset].table, AC_VLC_BITS, 3); if (index != ff_vc1_ac_sizes[codingset] - 1) { run = vc1_index_decode_table[codingset][index][0]; level = vc1_index_decode_table[codingset][index][1]; lst = index >= vc1_last_decode_table[codingset] || get_bits_left(gb) < 0; - if (get_bits1(gb)) - level = -level; + sign = get_bits1(gb); } else { - escape = decode210(gb); + int escape = decode210(gb); if (escape != 2) { index = get_vlc2(gb, ff_vc1_ac_coeff_table[codingset].table, AC_VLC_BITS, 3); run = vc1_index_decode_table[codingset][index][0]; @@ -514,10 +513,8 @@ static void vc1_decode_ac_coeff(VC1Context *v, int *last, int *skip, else run += vc1_delta_run_table[codingset][level] + 1; } - if (get_bits1(gb)) - level = -level; + sign = get_bits1(gb); } else { - int sign; lst = get_bits1(gb); if (v->s.esc3_level_length == 0) { if (v->pq < 8 || v->dquantfrm) { // table 59 @@ -532,14 +529,12 @@ static void vc1_decode_ac_coeff(VC1Context *v, int *last, int *skip, run = get_bits(gb, v->s.esc3_run_length); sign = get_bits1(gb); level = get_bits(gb, v->s.esc3_level_length); - if (sign) - level = -level; } } *last = lst; *skip = run; - *value = level; + *value = (level ^ -sign) + sign; } /** Decode intra block in intra frames - should be faster than decode_intra_block |