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Revert "Implement a new resampling algorithm in AudioStreamPlaybackResampled"

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This reverts commit b2264cb48b.
This commit is contained in:
Ellen Poe 2021-07-30 08:07:48 -07:00
parent 23bf04ae9a
commit 57ccfab5fb
1 changed files with 9 additions and 9 deletions
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18
servers/audio/audio_stream.cpp
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@ -54,21 +54,21 @@ void AudioStreamPlaybackResampled::mix(AudioFrame *p_buffer, float p_rate_scale,
for (int i = 0; i < p_frames; i++) { for (int i = 0; i < p_frames; i++) {
uint32_t idx = CUBIC_INTERP_HISTORY + uint32_t(mix_offset >> FP_BITS); uint32_t idx = CUBIC_INTERP_HISTORY + uint32_t(mix_offset >> FP_BITS);
// 4 point, 4th order optimal resampling algorithm from: http://yehar.com/blog/wp-content/uploads/2009/08/deip.pdf //standard cubic interpolation (great quality/performance ratio)
//this used to be moved to a LUT for greater performance, but nowadays CPU speed is generally faster than memory.
float mu = (mix_offset & FP_MASK) / float(FP_LEN); float mu = (mix_offset & FP_MASK) / float(FP_LEN);
AudioFrame y0 = internal_buffer[idx - 3]; AudioFrame y0 = internal_buffer[idx - 3];
AudioFrame y1 = internal_buffer[idx - 2]; AudioFrame y1 = internal_buffer[idx - 2];
AudioFrame y2 = internal_buffer[idx - 1]; AudioFrame y2 = internal_buffer[idx - 1];
AudioFrame y3 = internal_buffer[idx - 0]; AudioFrame y3 = internal_buffer[idx - 0];
AudioFrame even1 = y2 + y1, odd1 = y2 - y1; float mu2 = mu * mu;
AudioFrame even2 = y3 + y0, odd2 = y3 - y0; AudioFrame a0 = y3 - y2 - y0 + y1;
AudioFrame c0 = even1 * 0.46835497211269561 + even2 * 0.03164502784253309; AudioFrame a1 = y0 - y1 - a0;
AudioFrame c1 = odd1 * 0.56001293337091440 + odd2 * 0.14666238593949288; AudioFrame a2 = y2 - y0;
AudioFrame c2 = even1 * -0.250038759826233691 + even2 * 0.25003876124297131; AudioFrame a3 = y1;
AudioFrame c3 = odd1 * -0.49949850957839148 + odd2 * 0.16649935475113800;
AudioFrame c4 = even1 * 0.00016095224137360 + even2 * -0.00016095810460478; p_buffer[i] = (a0 * mu * mu2 + a1 * mu2 + a2 * mu + a3);
p_buffer[i] = (((c4 * mu + c3) * mu + c2) * mu + c1) * mu + c0;
mix_offset += mix_increment; mix_offset += mix_increment;