Every once in a while you might experience issues with uploading video. This may be due to:
1) The upload having failed because we couldn't convert one of the files.
2) Needing to compress the files because you're attempting to upload on a slow connection.
Handbrake is a great, free option for converting DVDs and video to MP4, compressing video files down to smaller sizes, or standardizing video resolution mis-matches:
For a walkthrough on how to use Handbrake to convert or re-encode your files, please see this article here.