hey
okay so i have a .ac3 audio file and the corresponding video file. but my video file has sound already. so basically i want to know how to remove the audio on my video file and then merge my .ac3 file with it
thanks

It'd help if we knew which video applications you have at your disposal. The file format of the video will also be relevant. There's also a possibility that your ac3 file will need converting to another format. Therefore, we'll need to know which audio apps you have.

I could write a book outlining the different ways to achieve what you want, with various file formats and software packages. Supplying the relevant details will result in more useful advice.

Please let us know if you found someone's advice to be helpful.