AudioMixerSubmixEffectEQ.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "DSP/EQ.h"
#include "Sound/SoundEffectSubmix.h"
#include "Sound/SoundMix.h"
#include "Stats/Stats.h"
 
#include "AudioMixerSubmixEffectEQ.generated.h"
 
// The time it takes to process the master EQ effect.
DECLARE_CYCLE_STAT_EXTERN(TEXT("Submix EQ"), STAT_AudioMixerSubmixEQ, STATGROUP_AudioMixer, AUDIOMIXER_API);
 
// A multiband EQ submix effect.
USTRUCT(BlueprintType)
struct FSubmixEffectEQBand
{
    GENERATED_USTRUCT_BODY()
 
    // Cutoff frequency (in hz) of the EQ band
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Equalizer, meta = (EditCondition = "bEnabled", DisplayName = "Cutoff Frequency (hz)", ClampMin = "20.0", ClampMax = "20000.0", UIMin = "20.0", UIMax = "15000.0"))
    float Frequency = 500.0f;
 
    // The bandwidth, in octaves, of the EQ band
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Equalizer, meta = (EditCondition = "bEnabled", DisplayName = "Bandwidth (octaves)", ClampMin = "0.1", ClampMax = "2.0", UIMin = "0.1", UIMax = "2.0"))
    float Bandwidth = 2.0f;
 
    // The gain in decibels of the EQ band
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Equalizer, meta = (EditCondition = "bEnabled", DisplayName = "Gain (dB)", ClampMin = "-90.0", ClampMax = "20.0", UIMin = "-90.0", UIMax = "20.0"))
    float GainDb = 0.0f;
 
    // Whether or not the EQ band is enabled
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Equalizer)
    uint32 bEnabled : 1;
 
    FSubmixEffectEQBand()
        : bEnabled(false)
    {
    }
};
 
// EQ submix effect
USTRUCT(BlueprintType)
struct FSubmixEffectSubmixEQSettings
{
    GENERATED_USTRUCT_BODY()
 
    // The EQ bands to use. 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "SubmixEffect|Preset")
    TArray<FSubmixEffectEQBand> EQBands;
};
 
class FSubmixEffectSubmixEQ : public FSoundEffectSubmix
{
public:
    AUDIOMIXER_API FSubmixEffectSubmixEQ();
 
    // Called on an audio effect at initialization on main thread before audio processing begins.
    AUDIOMIXER_API virtual void Init(const FSoundEffectSubmixInitData& InSampleRate) override;
 
    // Process the input block of audio. Called on audio thread.
    AUDIOMIXER_API virtual void OnProcessAudio(const FSoundEffectSubmixInputData& InData, FSoundEffectSubmixOutputData& OutData) override;
 
    // Sets the effect parameters using the old audio engine preset setting object
    AUDIOMIXER_API virtual bool SetParameters(const FAudioEffectParameters& InParameters) override;
 
    virtual bool SupportsDefaultEQ() const override
    {
        return true;
    }
 
    // Called when an audio effect preset is changed
    AUDIOMIXER_API virtual void OnPresetChanged() override;
 
protected:
    AUDIOMIXER_API void UpdateParameters(const int32 NumOutputChannels);
 
    // An EQ effect is a bank of biquad filters
    struct FEQ
    {
        bool bEnabled;
        TArray<Audio::FBiquadFilter> Bands;
 
        FEQ()
            : bEnabled(true)
        {}
    };
 
    // Each of these filters is a 2 channel biquad filter. 1 for each stereo pair
    TArray<FEQ> FiltersPerChannel;
 
    float ScratchInBuffer[2];
    float ScratchOutBuffer[2];
    float SampleRate;
    float NumOutputChannels;
    bool bEQSettingsSet;
 
    // A pending eq setting change
    Audio::TParams<FSubmixEffectSubmixEQSettings> PendingSettings;
 
    // Game thread copy of the eq setting
    FSubmixEffectSubmixEQSettings GameThreadEQSettings;
 
    // Audio render thread copy of the eq setting
    FSubmixEffectSubmixEQSettings RenderThreadEQSettings;
};
 
UCLASS(ClassGroup = AudioSourceEffect, meta = (BlueprintSpawnableComponent), MinimalAPI)
class USubmixEffectSubmixEQPreset : public USoundEffectSubmixPreset
{
    GENERATED_BODY()
 
public:
 
    EFFECT_PRESET_METHODS(SubmixEffectSubmixEQ)
 
    UFUNCTION(BlueprintCallable, Category = "Audio|Effects")
    AUDIOMIXER_API void SetSettings(const FSubmixEffectSubmixEQSettings& InSettings);
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = SubmixEffectPreset, meta = (ShowOnlyInnerProperties))
    FSubmixEffectSubmixEQSettings Settings;
};