[dba-Tech] A few questions about media files

I have a couple of quick questions about media files -- I can look these up later, but I thought I'd ask incase someone knows off the top of their heads -- would save me some research time. 

1.) Do MPEG, AVI, and GIF files support both sounds and video? 

2.) Can you convert a media file to another format? If so, can you recommend a product?

Susan H.