(This is the documentation for SDL3, which is under heavy development and the API is changing! SDL2 is the current stable version!)

SDL_SetAudioStreamFrequencyRatio

Change the frequency ratio of an audio stream.

Header File

Syntax

int SDL_SetAudioStreamFrequencyRatio(SDL_AudioStream *stream, float ratio);

Function Parameters

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

Return Value

Returns 0 on success, or -1 on error.

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 3.0.0.