Video download Help

Well I used the Media Converter Addon for Firefox and I hear from alot of people that this program is very reliable and safe. Well I downloaded it, and used it to download videos from Youtube to a 3g2 file yo put videos on my phone. Well success! And no Viruses or Spyware! But.... theres a little problem. When I play the video on my phone I only get a audio, no picture. I made sure I did it right, seeing as how my phone handles 3g2 files. But what I noticed is that videos that already in the phone (recorded myself) also have this BLT. File (BLT? Like the sandwich?) So I saw a video of a tutorial downloading a 3g2file into the phone with a person that has the same one as me but when he put the file into his phone it looked exactly like I did, just the 3g2 file, so I'm guessing this BLTfile isn't needed?