104 lines
2.3 KiB
C++
104 lines
2.3 KiB
C++
#include <psemek/audio/effect/pitch.hpp>
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#include <psemek/audio/resampler.hpp>
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#include <cmath>
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namespace psemek::audio
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{
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namespace
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{
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struct pitch_control_impl
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: pitch_control
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{
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pitch_control_impl(stream_ptr stream, float ratio, float smoothness)
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: stream_(std::move(stream))
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, resampler_(1.f / ratio, smoothness)
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{}
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// N.B. resampler ratio is in terms of sampling frequency, while
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// pitch control ratio is in terms of sound frequency, which
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// is the opposite
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float pitch() const override
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{
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return 1.f / resampler_.ratio();
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}
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float pitch(float ratio) override
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{
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return 1.f / resampler_.ratio(1.f / ratio);
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}
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float smoothness() const override
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{
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return resampler_.smoothness();
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}
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float smoothness(float value) override
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{
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return resampler_.smoothness(value);
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}
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std::optional<std::size_t> length() const override
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{
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return std::nullopt;
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}
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std::size_t read(float * data, std::size_t sample_count) override
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{
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std::size_t result = 0;
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while (result < sample_count)
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{
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if (resampler_pos_ < resampler_.result().size())
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{
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std::size_t size = std::min(sample_count - result, resampler_.result().size() - resampler_pos_);
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std::copy(resampler_.result().data() + resampler_pos_, resampler_.result().data() + resampler_pos_ + size, data + result);
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result += size;
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resampler_pos_ += size;
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played_ += size;
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}
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else
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{
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resampler_pos_ = 0;
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std::size_t request_size = std::max<std::size_t>(sample_count, std::ceil(resampler_.ratio() * sample_count / 2.f) * 2);
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source_buffer_.resize(request_size);
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auto count = stream_->read(source_buffer_.data(), request_size);
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if (count == 0)
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break;
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resampler_.feed({source_buffer_.data(), source_buffer_.data() + count});
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}
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}
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return result;
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}
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std::size_t played() const override
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{
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return played_.load();
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}
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private:
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stream_ptr stream_;
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std::vector<float> source_buffer_;
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resampler resampler_;
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std::size_t resampler_pos_{0};
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std::atomic<std::size_t> played_{0};
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};
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}
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std::shared_ptr<pitch_control> pitch(stream_ptr stream, float ratio, float smoothness)
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{
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return std::make_shared<pitch_control_impl>(std::move(stream), ratio, smoothness);
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}
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}
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