To "put together" or convert the file (or its source parts), you can use free tools like VLC Media Player or FFmpeg .
: Click Convert / Save at the bottom. Under Profile , choose Video - H.264 + MP3 (MP4) . RTS0052 2 mp4
: Click the Wrench icon (settings) → Audio codec tab → Check Keep original audio track to avoid losing sound quality. To "put together" or convert the file (or