diff options
| author | Michael Niedermayer <michaelni@gmx.at> | 2006-08-25 11:55:20 +0000 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2006-08-25 11:55:20 +0000 |
| commit | 55017f35da511ab1b99b6c19d9731fbe69322cb6 (patch) | |
| tree | 8a38a6307329fe28e1c93bff46096f43ac519b70 /libavcodec/mpegaudiodec.c | |
| parent | f8347c41671199c119843debde48f477961ace9f (diff) | |
try to avoid l3_unscale() by using a table
Originally committed as revision 6083 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/mpegaudiodec.c')
| -rw-r--r-- | libavcodec/mpegaudiodec.c | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/libavcodec/mpegaudiodec.c b/libavcodec/mpegaudiodec.c index e7fba1f2da..328048645d 100644 --- a/libavcodec/mpegaudiodec.c +++ b/libavcodec/mpegaudiodec.c @@ -174,6 +174,7 @@ static uint16_t band_index_long[9][23]; static int8_t *table_4_3_exp; static uint32_t *table_4_3_value; static uint32_t exp_table[512]; +static uint32_t expval_table[512][16]; /* intensity stereo coef table */ static int32_t is_table[2][16]; static int32_t is_table_lsf[2][2][16]; @@ -429,10 +430,12 @@ static int decode_init(AVCodecContext * avctx) // av_log(NULL, AV_LOG_DEBUG, "%d %d %f\n", i, m, pow((double)i, 4.0 / 3.0)); table_4_3_exp[i] = -e; } - for(i=0; i<512; i++){ - int exponent= i-400; - double f= pow(1, 4.0 / 3.0) * pow(2, exponent*0.25 + FRAC_BITS + 5); - exp_table[i]= lrintf(f); + for(i=0; i<512*16; i++){ + int exponent= (i>>4)-400; + double f= pow(i&15, 4.0 / 3.0) * pow(2, exponent*0.25 + FRAC_BITS + 5); + expval_table[exponent+400][i&15]= lrintf(f); + if((i&15)==1) + exp_table[exponent+400]= lrintf(f); } for(i=0;i<7;i++) { @@ -1717,9 +1720,18 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, dprintf("region=%d n=%d x=%d y=%d exp=%d\n", i, g->region_size[i] - j, x, y, exponents[s_index]); if (x) { +#if 0 if (x == 15) x += get_bitsz(&s->gb, linbits); v = l3_unscale(x, exponents[s_index]); +#else + if (x < 15){ + v = expval_table[ exponents[s_index] + 400 ][ x ]; + }else{ + x += get_bitsz(&s->gb, linbits); + v = l3_unscale(x, exponents[s_index]); + } +#endif if (get_bits1(&s->gb)) v = -v; } else { @@ -1727,9 +1739,18 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, } g->sb_hybrid[s_index++] = v; if (y) { +#if 0 if (y == 15) y += get_bitsz(&s->gb, linbits); v = l3_unscale(y, exponents[s_index]); +#else + if (y < 15){ + v = expval_table[ exponents[s_index] + 400 ][ y ]; + }else{ + y += get_bitsz(&s->gb, linbits); + v = l3_unscale(y, exponents[s_index]); + } +#endif if (get_bits1(&s->gb)) v = -v; } else { |