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avoid reading exponent twice

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Originally committed as revision 6085 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-08-25 13:36:27 +00:00
parent 1f1d675b68
commit 9b49f89cdf
1 changed files with 11 additions and 7 deletions
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18
libavcodec/mpegaudiodec.c
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@ -1703,6 +1703,8 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
/* read huffcode and compute each couple */
for(;j>0;j--) {
int exponent;
if (get_bits_count(&s->gb) >= end_pos)
break;
y = get_vlc2(&s->gb, vlc->table, 7, 3);
@ -1716,20 +1718,22 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
x = y >> 4;
y = y & 0x0f;
exponent= exponents[s_index];
dprintf("region=%d n=%d x=%d y=%d exp=%d\n",
i, g->region_size[i] - j, x, y, exponents[s_index]);
i, g->region_size[i] - j, x, y, exponent);
if (x) {
#if 0
if (x == 15)
x += get_bitsz(&s->gb, linbits);
v = l3_unscale(x, exponents[s_index]);
v = l3_unscale(x, exponent);
#else
if (x < 15){
v = expval_table[ exponents[s_index] + 400 ][ x ];
v = expval_table[ exponent + 400 ][ x ];
// v = expval_table[ (exponent&3) + 400 ][ x ] >> FFMIN(0 - (exponent>>2), 31);
}else{
x += get_bitsz(&s->gb, linbits);
v = l3_unscale(x, exponents[s_index]);
v = l3_unscale(x, exponent);
}
#endif
if (get_bits1(&s->gb))
@ -1742,13 +1746,13 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
#if 0
if (y == 15)
y += get_bitsz(&s->gb, linbits);
v = l3_unscale(y, exponents[s_index]);
v = l3_unscale(y, exponent);
#else
if (y < 15){
v = expval_table[ exponents[s_index] + 400 ][ y ];
v = expval_table[ exponent + 400 ][ y ];
}else{
y += get_bitsz(&s->gb, linbits);
v = l3_unscale(y, exponents[s_index]);
v = l3_unscale(y, exponent);
}
#endif
if (get_bits1(&s->gb))