mirror of https://git.ffmpeg.org/ffmpeg.git
adpcmenc:Optimize adpcm_ima_qt_compress_sample()
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
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@ -274,24 +274,27 @@ static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, sho
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static inline unsigned char adpcm_ima_qt_compress_sample(ADPCMChannelStatus *c, short sample)
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{
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int delta = sample - c->prev_sample;
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int mask, step = step_table[c->step_index];
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int diff = step >> 3;
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int nibble = 0;
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int diff, step = step_table[c->step_index];
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int nibble = 8*(delta < 0);
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if (delta < 0) {
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nibble = 8;
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delta = -delta;
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}
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delta= abs(delta);
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diff = delta + (step >> 3);
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for (mask = 4; mask;) {
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if (delta >= step) {
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nibble |= mask;
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delta -= step;
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diff += step;
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}
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step >>= 1;
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mask >>= 1;
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if (delta >= step) {
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nibble |= 4;
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delta -= step;
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}
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step >>= 1;
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if (delta >= step) {
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nibble |= 2;
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delta -= step;
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}
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step >>= 1;
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if (delta >= step) {
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nibble |= 1;
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delta -= step;
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}
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diff -= delta;
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if (nibble & 8)
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c->prev_sample -= diff;
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