(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_SetAudioStreamFrequencyRatio

Change the frequency ratio of an audio stream.

Header File

Syntax

bool SDL_SetAudioStreamFrequencyRatio(SDL_AudioStream *stream, float ratio);

Function Parameters

SDL_AudioStream *	stream	the stream the frequency ratio is being changed.
float	ratio	the frequency ratio. 1.0 is normal speed. Must be between 0.01 and 100.

Return Value

(bool) Returns true on success or false on failure; call SDL_GetError() for more information.

Remarks

The frequency ratio is used to adjust the rate at which input data is consumed. Changing this effectively modifies the speed and pitch of the audio. A value greater than 1.0 will play the audio faster, and at a higher pitch. A value less than 1.0 will play the audio slower, and at a lower pitch.

This is applied during SDL_GetAudioStreamData, and can be continuously changed to create various effects.

Thread Safety

It is safe to call this function from any thread, as it holds a stream-specific mutex while running.

Version

This function is available since SDL 3.1.3.