Duckstation/src/common/audio_stream.h
2021-02-22 12:21:44 +10:00

128 lines
3.5 KiB
C++

#pragma once
#include "fifo_queue.h"
#include "types.h"
#include <atomic>
#include <condition_variable>
#include <memory>
#include <mutex>
#include <vector>
// Uses signed 16-bits samples.
class AudioStream
{
public:
using SampleType = s16;
enum : u32
{
DefaultInputSampleRate = 44100,
DefaultOutputSampleRate = 44100,
DefaultBufferSize = 2048,
MaxSamples = 32768,
FullVolume = 100
};
AudioStream();
virtual ~AudioStream();
u32 GetOutputSampleRate() const { return m_output_sample_rate; }
u32 GetChannels() const { return m_channels; }
u32 GetBufferSize() const { return m_buffer_size; }
s32 GetOutputVolume() const { return m_output_volume; }
bool IsSyncing() const { return m_sync; }
bool Reconfigure(u32 input_sample_rate = DefaultInputSampleRate, u32 output_sample_rate = DefaultOutputSampleRate,
u32 channels = 1, u32 buffer_size = DefaultBufferSize);
void SetSync(bool enable) { m_sync = enable; }
void SetInputSampleRate(u32 sample_rate);
void SetWaitForBufferFill(bool enabled);
virtual void SetOutputVolume(u32 volume);
void PauseOutput(bool paused);
void EmptyBuffers();
void Shutdown();
void BeginWrite(SampleType** buffer_ptr, u32* num_frames);
void WriteFrames(const SampleType* frames, u32 num_frames);
void EndWrite(u32 num_frames);
bool DidUnderflow()
{
bool expected = true;
return m_underflow_flag.compare_exchange_strong(expected, false);
}
static std::unique_ptr<AudioStream> CreateNullAudioStream();
// Latency computation - returns values in seconds
static float GetMaxLatency(u32 sample_rate, u32 buffer_size);
protected:
virtual bool OpenDevice() = 0;
virtual void PauseDevice(bool paused) = 0;
virtual void CloseDevice() = 0;
virtual void FramesAvailable() = 0;
ALWAYS_INLINE static SampleType ApplyVolume(SampleType sample, u32 volume)
{
return s16((s32(sample) * s32(volume)) / 100);
}
bool SetBufferSize(u32 buffer_size);
bool IsDeviceOpen() const { return (m_output_sample_rate > 0); }
void LockedEmptyBuffers();
u32 GetSamplesAvailable() const;
u32 GetSamplesAvailableLocked() const;
void ReadFrames(SampleType* samples, u32 num_frames, bool apply_volume);
void DropFrames(u32 count);
u32 m_input_sample_rate = 0;
u32 m_output_sample_rate = 0;
u32 m_channels = 0;
u32 m_buffer_size = 0;
// volume, 0-100
u32 m_output_volume = FullVolume;
private:
ALWAYS_INLINE u32 GetBufferSpace() const { return (m_max_samples - m_buffer.GetSize()); }
ALWAYS_INLINE void ReleaseBufferLock(std::unique_lock<std::mutex> lock)
{
// lock is released implicitly by destruction
m_buffer_draining_cv.notify_one();
}
void EnsureBuffer(u32 size);
void CreateResampler();
void DestroyResampler();
void ResetResampler();
void InternalSetInputSampleRate(u32 sample_rate);
void ResampleInput(std::unique_lock<std::mutex> buffer_lock);
HeapFIFOQueue<SampleType, MaxSamples> m_buffer;
mutable std::mutex m_buffer_mutex;
std::condition_variable m_buffer_draining_cv;
std::vector<SampleType> m_resample_buffer;
std::atomic_bool m_underflow_flag{false};
std::atomic_bool m_buffer_filling{false};
u32 m_max_samples = 0;
bool m_output_paused = true;
bool m_sync = true;
bool m_wait_for_buffer_fill = false;
// Resampling
double m_resampler_ratio = 1.0;
void* m_resampler_state = nullptr;
std::mutex m_resampler_mutex;
HeapFIFOQueue<SampleType, MaxSamples> m_resampled_buffer;
std::vector<float> m_resample_in_buffer;
std::vector<float> m_resample_out_buffer;
};