Use this service to add audio or music to a video file online and for free. You can add audio (in mp3 format) to a video file (avi, mp4, mov, wmv). This service replaces the audio of the video file with the selected mp3 audio file. Just select the video and audio file, then click the "Upload" button. It may take some time depending on the video file size.
NEW FREE TOOL Compress Multimedia Files Online