I have tried exporting a video where I have added a sound wave that has more than 19000hz, but when I export it as QuickTime, the video doesn't have any sound that is greater than 19000hz ( I tested using soundbeam app on my iPhone) can some one help me with the settings? the software i'm using is iMovie. What is the software that i can use?
Most lossy compression of audio will filter out such sounds. If you need to guarantee that the sound is in the final export, you will need to use straight PCM audio (or some lossless audio codec). Almost all video containers support this.