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


Change the frequency ratio of an audio stream.

Header File

Defined in <SDL3/SDL_audio.h>


int 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

(int) Returns 0 on success, or -1 on error.


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.


This function is available since SDL 3.0.0.

See Also

CategoryAPI, CategoryAPIFunction, CategoryAudio

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