[SCM] libav/experimental: Init simplification and 2% faster wma_decode_block on amd64 with tables use instead of pow().
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 15:46:55 UTC 2013
The following commit has been merged in the experimental branch:
commit 6f3dda9328568b38e81580d6cdf6f4ffdbbe07df
Author: Benjamin Larsson <banan at ludd.ltu.se>
Date: Wed Mar 8 09:26:57 2006 +0000
Init simplification and 2% faster wma_decode_block on amd64 with tables use
instead of pow().
Originally committed as revision 5126 to svn://svn.ffmpeg.org/ffmpeg/trunk
diff --git a/libavcodec/wmadec.c b/libavcodec/wmadec.c
index 5bf87ac..95dbf33 100644
--- a/libavcodec/wmadec.c
+++ b/libavcodec/wmadec.c
@@ -130,6 +130,9 @@ typedef struct WMADecodeContext {
float lsp_pow_e_table[256];
float lsp_pow_m_table1[(1 << LSP_POW_BITS)];
float lsp_pow_m_table2[(1 << LSP_POW_BITS)];
+ /* pow tables */
+ float pow_005_10[121];
+ float pow_00625_10[121];
#ifdef TRACE
int frame_count;
@@ -218,8 +221,8 @@ static int wma_decode_init(AVCodecContext * avctx)
int i, flags1, flags2;
float *window;
uint8_t *extradata;
- float bps1, high_freq;
- volatile float bps;
+ float bps, bps1;
+ volatile float high_freq_factor;
int sample_rate1;
int coef_vlc_table;
@@ -275,7 +278,6 @@ static int wma_decode_init(AVCodecContext * avctx)
/* init rate dependant parameters */
s->use_noise_coding = 1;
- high_freq = s->sample_rate * 0.5;
/* if version 2, then the rates are normalized */
sample_rate1 = s->sample_rate;
@@ -304,44 +306,44 @@ static int wma_decode_init(AVCodecContext * avctx)
if (bps1 >= 0.61)
s->use_noise_coding = 0;
else
- high_freq = high_freq * 0.4;
+ high_freq_factor = 0.4;
} else if (sample_rate1 == 22050) {
if (bps1 >= 1.16)
s->use_noise_coding = 0;
else if (bps1 >= 0.72)
- high_freq = high_freq * 0.7;
+ high_freq_factor = 0.7;
else
- high_freq = high_freq * 0.6;
+ high_freq_factor = 0.6;
} else if (sample_rate1 == 16000) {
if (bps > 0.5)
- high_freq = high_freq * 0.5;
+ high_freq_factor = 0.5;
else
- high_freq = high_freq * 0.3;
+ high_freq_factor = 0.3;
} else if (sample_rate1 == 11025) {
- high_freq = high_freq * 0.7;
+ high_freq_factor = 0.7;
} else if (sample_rate1 == 8000) {
if (bps <= 0.625) {
- high_freq = high_freq * 0.5;
+ high_freq_factor = 0.5;
} else if (bps > 0.75) {
s->use_noise_coding = 0;
} else {
- high_freq = high_freq * 0.65;
+ high_freq_factor = 0.65;
}
} else {
if (bps >= 0.8) {
- high_freq = high_freq * 0.75;
+ high_freq_factor = 0.75;
} else if (bps >= 0.6) {
- high_freq = high_freq * 0.6;
+ high_freq_factor = 0.6;
} else {
- high_freq = high_freq * 0.5;
+ high_freq_factor = 0.5;
}
}
dprintf("flags1=0x%x flags2=0x%x\n", flags1, flags2);
dprintf("version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
s->version, s->nb_channels, s->sample_rate, s->bit_rate,
s->block_align);
- dprintf("bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
- bps, bps1, high_freq, s->byte_offset_bits);
+ dprintf("bps=%f bps1=%f bitoffset=%d\n",
+ bps, bps1, s->byte_offset_bits);
dprintf("use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
@@ -414,8 +416,8 @@ static int wma_decode_init(AVCodecContext * avctx)
/* max number of coefs */
s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
/* high freq computation */
- s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
- s->sample_rate + 0.5);
+ s->high_band_start[k] = (int)((block_len * high_freq_factor) + 0.5);
+
n = s->exponent_sizes[k];
j = 0;
pos = 0;
@@ -527,6 +529,13 @@ static int wma_decode_init(AVCodecContext * avctx)
&coef_vlcs[coef_vlc_table * 2]);
init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1],
&coef_vlcs[coef_vlc_table * 2 + 1]);
+
+ /* init pow tables */
+ for (i=0 ; i<121 ; i++) {
+ s->pow_005_10[i] = pow(10, i * 0.05);
+ s->pow_00625_10[i] = pow(10, i * (1.0 / 16.0));
+ }
+
return 0;
}
@@ -678,8 +687,7 @@ static int decode_exp_vlc(WMADecodeContext *s, int ch)
max_scale = 0;
if (s->version == 1) {
last_exp = get_bits(&s->gb, 5) + 10;
- /* XXX: use a table */
- v = pow(10, last_exp * (1.0 / 16.0));
+ v = s->pow_00625_10[last_exp];
max_scale = v;
n = *ptr++;
do {
@@ -693,8 +701,7 @@ static int decode_exp_vlc(WMADecodeContext *s, int ch)
return -1;
/* NOTE: this offset is the same as MPEG4 AAC ! */
last_exp += code - 60;
- /* XXX: use a table */
- v = pow(10, last_exp * (1.0 / 16.0));
+ v = s->pow_00625_10[last_exp];
if (v > max_scale)
max_scale = v;
n = *ptr++;
@@ -939,7 +946,7 @@ static int wma_decode_block(WMADecodeContext *s)
coefs1 = s->coefs1[ch];
exponents = s->exponents[ch];
- mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];
+ mult = s->pow_005_10[total_gain] / s->max_exponent[ch];
mult *= mdct_norm;
coefs = s->coefs[ch];
if (s->use_noise_coding) {
@@ -986,8 +993,7 @@ static int wma_decode_block(WMADecodeContext *s)
if (j >= 0 && s->high_band_coded[ch][j]) {
/* use noise with specified power */
mult1 = sqrt(exp_power[j] / exp_power[last_high_band]);
- /* XXX: use a table */
- mult1 = mult1 * pow(10, s->high_band_values[ch][j] * 0.05);
+ mult1 = mult1 * s->pow_005_10[s->high_band_values[ch][j]];
mult1 = mult1 / (s->max_exponent[ch] * s->noise_mult);
mult1 *= mdct_norm;
for(i = 0;i < n; i++) {
--
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