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Rearrange loop structure for approx. 35-50% faster calc_transform_coeffs_cpl()

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Originally committed as revision 20055 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2009-09-27 07:16:51 +00:00
parent e96f885aa0
commit 8b11b44ea7
1 changed files with 11 additions and 6 deletions
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17
libavcodec/ac3dec.c
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@ -416,17 +416,22 @@ static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
bin = s->start_freq[CPL_CH]; bin = s->start_freq[CPL_CH];
for (band = 0; band < s->num_cpl_bands; band++) { for (band = 0; band < s->num_cpl_bands; band++) {
int band_start = bin;
int band_end = bin + s->cpl_band_sizes[band]; int band_end = bin + s->cpl_band_sizes[band];
for (; bin < band_end; bin++) { for (ch = 1; ch <= s->fbw_channels; ch++) {
for (ch = 1; ch <= s->fbw_channels; ch++) { if (s->channel_in_cpl[ch]) {
if (s->channel_in_cpl[ch]) { int64_t cpl_coord = s->cpl_coords[ch][band];
for (bin = band_start; bin < band_end; bin++) {
s->fixed_coeffs[ch][bin] = ((int64_t)s->fixed_coeffs[CPL_CH][bin] * s->fixed_coeffs[ch][bin] = ((int64_t)s->fixed_coeffs[CPL_CH][bin] *
(int64_t)s->cpl_coords[ch][band]) >> 23; cpl_coord) >> 23;
if (ch == 2 && s->phase_flags[band]) }
s->fixed_coeffs[ch][bin] = -s->fixed_coeffs[ch][bin]; if (ch == 2 && s->phase_flags[band]) {
for (bin = band_start; bin < band_end; bin++)
s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin];
} }
} }
} }
bin = band_end;
} }
} }