Video uploads to Youtube with no sound
Sometimes, YouTube just doesn't like a certain file format. The camera may be creating the file in such a way that YouTube just can't decode the audio layer. Try using a program like HandBrake to re-encode the video before uploading it. This would ensure that it is encoded in a way that YouTube will definitely be able to understand, as long as HandBrake itself is capable of handling the audio. HandBrake is free software, and it has very good speed and quality, but if you are worried about quality, you can change the settings.