It is important to note that some video formats embed the GPS/GPX information inside the video file. So if you modify the file in any way, for example either removing audio or resizing then the GPS/GPX data will be lost and can't be used anymore for anything other than just playing back. So if you want to upload a file, then please leave the video file in its original state. If you want to mute your video, an option will be available for you to do that when you begin uploading your files.
You don't need to register to upload files.