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authorJames Rowe <jroweboy@gmail.com>2018-01-12 03:21:20 +0100
committerJames Rowe <jroweboy@gmail.com>2018-01-13 03:11:03 +0100
commitebf9a784a9f7f4148a669dbb39e7cd50df779a14 (patch)
treed585685a1c0a34b903af1d086d62560bf56bb29f /src/audio_core/time_stretch.cpp
parentconfig: Default CPU core to Unicorn. (diff)
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Diffstat (limited to 'src/audio_core/time_stretch.cpp')
-rw-r--r--src/audio_core/time_stretch.cpp143
1 files changed, 0 insertions, 143 deletions
diff --git a/src/audio_core/time_stretch.cpp b/src/audio_core/time_stretch.cpp
deleted file mode 100644
index 437cf9752..000000000
--- a/src/audio_core/time_stretch.cpp
+++ /dev/null
@@ -1,143 +0,0 @@
-// Copyright 2016 Citra Emulator Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <chrono>
-#include <cmath>
-#include <vector>
-#include <SoundTouch.h>
-#include "audio_core/audio_core.h"
-#include "audio_core/time_stretch.h"
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "common/math_util.h"
-
-using steady_clock = std::chrono::steady_clock;
-
-namespace AudioCore {
-
-constexpr double MIN_RATIO = 0.1;
-constexpr double MAX_RATIO = 100.0;
-
-static double ClampRatio(double ratio) {
- return MathUtil::Clamp(ratio, MIN_RATIO, MAX_RATIO);
-}
-
-constexpr double MIN_DELAY_TIME = 0.05; // Units: seconds
-constexpr double MAX_DELAY_TIME = 0.25; // Units: seconds
-constexpr size_t DROP_FRAMES_SAMPLE_DELAY = 16000; // Units: samples
-
-constexpr double SMOOTHING_FACTOR = 0.007;
-
-struct TimeStretcher::Impl {
- soundtouch::SoundTouch soundtouch;
-
- steady_clock::time_point frame_timer = steady_clock::now();
- size_t samples_queued = 0;
-
- double smoothed_ratio = 1.0;
-
- double sample_rate = static_cast<double>(native_sample_rate);
-};
-
-std::vector<s16> TimeStretcher::Process(size_t samples_in_queue) {
- // This is a very simple algorithm without any fancy control theory. It works and is stable.
-
- double ratio = CalculateCurrentRatio();
- ratio = CorrectForUnderAndOverflow(ratio, samples_in_queue);
- impl->smoothed_ratio =
- (1.0 - SMOOTHING_FACTOR) * impl->smoothed_ratio + SMOOTHING_FACTOR * ratio;
- impl->smoothed_ratio = ClampRatio(impl->smoothed_ratio);
-
- // SoundTouch's tempo definition the inverse of our ratio definition.
- impl->soundtouch.setTempo(1.0 / impl->smoothed_ratio);
-
- std::vector<s16> samples = GetSamples();
- if (samples_in_queue >= DROP_FRAMES_SAMPLE_DELAY) {
- samples.clear();
- LOG_TRACE(Audio, "Dropping frames!");
- }
- return samples;
-}
-
-TimeStretcher::TimeStretcher() : impl(std::make_unique<Impl>()) {
- impl->soundtouch.setPitch(1.0);
- impl->soundtouch.setChannels(2);
- impl->soundtouch.setSampleRate(native_sample_rate);
- Reset();
-}
-
-TimeStretcher::~TimeStretcher() {
- impl->soundtouch.clear();
-}
-
-void TimeStretcher::SetOutputSampleRate(unsigned int sample_rate) {
- impl->sample_rate = static_cast<double>(sample_rate);
- impl->soundtouch.setRate(static_cast<double>(native_sample_rate) / impl->sample_rate);
-}
-
-void TimeStretcher::AddSamples(const s16* buffer, size_t num_samples) {
- impl->soundtouch.putSamples(buffer, static_cast<uint>(num_samples));
- impl->samples_queued += num_samples;
-}
-
-void TimeStretcher::Flush() {
- impl->soundtouch.flush();
-}
-
-void TimeStretcher::Reset() {
- impl->soundtouch.setTempo(1.0);
- impl->soundtouch.clear();
- impl->smoothed_ratio = 1.0;
- impl->frame_timer = steady_clock::now();
- impl->samples_queued = 0;
- SetOutputSampleRate(native_sample_rate);
-}
-
-double TimeStretcher::CalculateCurrentRatio() {
- const steady_clock::time_point now = steady_clock::now();
- const std::chrono::duration<double> duration = now - impl->frame_timer;
-
- const double expected_time =
- static_cast<double>(impl->samples_queued) / static_cast<double>(native_sample_rate);
- const double actual_time = duration.count();
-
- double ratio;
- if (expected_time != 0) {
- ratio = ClampRatio(actual_time / expected_time);
- } else {
- ratio = impl->smoothed_ratio;
- }
-
- impl->frame_timer = now;
- impl->samples_queued = 0;
-
- return ratio;
-}
-
-double TimeStretcher::CorrectForUnderAndOverflow(double ratio, size_t sample_delay) const {
- const size_t min_sample_delay = static_cast<size_t>(MIN_DELAY_TIME * impl->sample_rate);
- const size_t max_sample_delay = static_cast<size_t>(MAX_DELAY_TIME * impl->sample_rate);
-
- if (sample_delay < min_sample_delay) {
- // Make the ratio bigger.
- ratio = ratio > 1.0 ? ratio * ratio : sqrt(ratio);
- } else if (sample_delay > max_sample_delay) {
- // Make the ratio smaller.
- ratio = ratio > 1.0 ? sqrt(ratio) : ratio * ratio;
- }
-
- return ClampRatio(ratio);
-}
-
-std::vector<s16> TimeStretcher::GetSamples() {
- uint available = impl->soundtouch.numSamples();
-
- std::vector<s16> output(static_cast<size_t>(available) * 2);
-
- impl->soundtouch.receiveSamples(output.data(), available);
-
- return output;
-}
-
-} // namespace AudioCore