How to change the sample rate
1. Drop one audio file you already have. Video and pictures are refused here. 2. Pick the rate the next tool expects. 16 kHz is the usual speech rate. 44.1 kHz is the CD rate. 48 kHz is the video rate. 3. Press “Change sample rate” and check the download in the app that asked for that rate.
GustKit runs FFmpeg aresample in this tab and re-encodes the file. WAV stays WAV, MP3 stays MP3. The length stays about the same. A higher rate does not invent detail that the original never had. Keep the original until the new file plays where you need it.
Sample rate is not speed and not volume
Change audio speed shortens or stretches the file and keeps the rate. Change volume makes the same recording louder or quieter. Stereo to mono mixes the channels and does not set the rate. This page only changes how many samples are stored each second.
The audio stays in this tab
The first visit downloads FFmpeg. Later visits reuse the browser cache. A file longer than the limit on the page is refused, because the whole file is re-encoded here. GustKit does not fetch audio from a link.
How to check the new rate before you send the file
1. Play the download from the start and from near the end. The words should still face forward. 2. Open the file info in the app that asked for the rate and confirm the number. 3. If that app still refuses the file, run again at the rate it named.
8 kHz is the smallest file of the five. 16 kHz is the usual speech rate. 44.1 kHz matches a CD. 48 kHz matches most video. The length stays about the same. Nothing is uploaded.