diff options
Diffstat (limited to 'servers/audio/audio_stream.cpp')
| -rw-r--r-- | servers/audio/audio_stream.cpp | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/servers/audio/audio_stream.cpp b/servers/audio/audio_stream.cpp index aec6932326..f3fa857682 100644 --- a/servers/audio/audio_stream.cpp +++ b/servers/audio/audio_stream.cpp @@ -48,27 +48,27 @@ void AudioStreamPlaybackResampled::_begin_resample() { void AudioStreamPlaybackResampled::mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) { float target_rate = AudioServer::get_singleton()->get_mix_rate(); - float global_rate_scale = AudioServer::get_singleton()->get_global_rate_scale(); + float playback_speed_scale = AudioServer::get_singleton()->get_playback_speed_scale(); - uint64_t mix_increment = uint64_t(((get_stream_sampling_rate() * p_rate_scale) / double(target_rate * global_rate_scale)) * double(FP_LEN)); + uint64_t mix_increment = uint64_t(((get_stream_sampling_rate() * p_rate_scale * playback_speed_scale) / double(target_rate)) * double(FP_LEN)); for (int i = 0; i < p_frames; i++) { 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); AudioFrame y0 = internal_buffer[idx - 3]; AudioFrame y1 = internal_buffer[idx - 2]; AudioFrame y2 = internal_buffer[idx - 1]; AudioFrame y3 = internal_buffer[idx - 0]; - AudioFrame even1 = y2 + y1, odd1 = y2 - y1; - AudioFrame even2 = y3 + y0, odd2 = y3 - y0; - AudioFrame c0 = even1 * 0.46835497211269561 + even2 * 0.03164502784253309; - AudioFrame c1 = odd1 * 0.56001293337091440 + odd2 * 0.14666238593949288; - AudioFrame c2 = even1 * -0.250038759826233691 + even2 * 0.25003876124297131; - AudioFrame c3 = odd1 * -0.49949850957839148 + odd2 * 0.16649935475113800; - AudioFrame c4 = even1 * 0.00016095224137360 + even2 * -0.00016095810460478; - p_buffer[i] = (((c4 * mu + c3) * mu + c2) * mu + c1) * mu + c0; + float mu2 = mu * mu; + AudioFrame a0 = 3 * y1 - 3 * y2 + y3 - y0; + AudioFrame a1 = 2 * y0 - 5 * y1 + 4 * y2 - y3; + AudioFrame a2 = y2 - y0; + AudioFrame a3 = 2 * y1; + + p_buffer[i] = (a0 * mu * mu2 + a1 * mu2 + a2 * mu + a3) / 2; mix_offset += mix_increment; |