You can also try looking up the file with Bitzi. Right click on the file you want , go down to advanced , click on Look Up File With Bitzi.
If anyone has submitted the file it should tell you if its good or not. Like deepblue I stick with .avi or .mpg files.
Also if a video, especially large files like 500mb or more, has a lot of sources and nothing shows up on bitzi, I would be suspicious.

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