Blitz3D+ Command Reference

AudioGroupPeak# ( group[,speaker] )

Parameters

group - mixing group:
0: SFX (default for LoadSound/Load3DSound)
1: Music (default for non-MIDI PlayMusic)
2: UI
3: Ambience

speaker (optional) - speaker index; 0 aggregates all speakers (default)

Description

Returns a mixing group's peak amplitude from the last audio block.

Metering must be enabled with AudioGroupMeter. Returns a linear amplitude from the last audio processing block. Values above 1 are valid. Speaker 0 aggregates all speakers: peak is the maximum, RMS is the square root of the mean squared speaker RMS. Speakers 1..N follow the output speaker-mask bit order: stereo L/R; 5.1 FL/FR/FC/LFE/BL/BR (or SL/SR for the side layout); 7.1 FL/FR/FC/LFE/BL/BR/SL/SR. Disabled meters return 0. Invalid indexes return 0 and set AudioLastError. Successful queries preserve the previous error. Readings are neither peak hold nor LUFS.

Call InitAudioEffects before the first WAV/Ogg playback. Configuration commands return 1 on success or 0 on failure; use AudioLastError for the reason. Finite numeric values and valid handles are required in Debug and Release. Queries preserve errors unless the query itself fails.

Audio effects process decoded WAV and mono/stereo Ogg at an internal 48 kHz. MIDI uses a separate backend. Sound defaults are copied to independent playing channels. Runtime pause freezes sources, tails and transition time; pausing one channel leaves shared tails running. Event waits service transitions and release completed source resources without ChannelPlaying polling. Lightweight completed handles are retained until program shutdown.

The interactive Audio Playground sample demonstrates the whole effects family together.

Requires Extended mode.

See also: AudioGroupRMS, AudioGroupMeter, AudioMasterPeak.

Example

; AudioGroupPeak example. Compile in Extended mode; media ships with Audio Playground.
AppTitle "AudioGroupPeak"
If Not InitAudioEffects() Then RuntimeError AudioLastError$()
Graphics 680,240,0,2
SetBuffer BackBuffer()
sound = LoadSound("../../../samples/audio/media/machine.wav")
If sound = 0 Then RuntimeError "The installed audio sample media is missing."
LoopSound sound
SoundVolume sound,0.25
RequireAudio AudioMasterMeter(True)
RequireAudio AudioGroupMeter(0,True)
message$ = "AudioGroupPeak"
RequireAudio AudioGroupMeter(0,True)
channel = PlaySound(sound)
If channel = 0 Then RuntimeError "Unable to play the example sound."

started = MilliSecs()
While KeyDown(1) = False And MilliSecs()-started < 5000

    Cls
    Text 20,20,message
    Text 20,50,"Group 0 peak: " + AudioGroupPeak(0) + "   RMS: " + AudioGroupRMS(0)
    Text 20,80,"Master peak: " + AudioMasterPeak() + "   RMS: " + AudioMasterRMS()
    Text 20,120,"Listen for five seconds, or press Escape to finish."
    Flip
Wend
StopChannel channel
For group = 0 To 3
    RequireAudio AudioGroupClearEffects(group)
Next
Delay 60
FreeSound sound
EndGraphics
End

Function RequireAudio(success)
    If Not success Then RuntimeError AudioLastError$()
End Function

Index