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author | James Rowe <jroweboy@gmail.com> | 2018-01-12 03:21:20 +0100 |
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committer | James Rowe <jroweboy@gmail.com> | 2018-01-13 03:11:03 +0100 |
commit | ebf9a784a9f7f4148a669dbb39e7cd50df779a14 (patch) | |
tree | d585685a1c0a34b903af1d086d62560bf56bb29f /src/audio_core/time_stretch.cpp | |
parent | config: Default CPU core to Unicorn. (diff) | |
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Diffstat (limited to '')
-rw-r--r-- | src/audio_core/time_stretch.cpp | 143 |
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 |