What is causing Unity to crash when importing a mp4?

Hello,

I am working on a virtual reality film that requires the use of very high res textures. The issue that I have run into is that when I import a mp4, the file imports as only a fraction of the size of the actual file. I click the play button in the previewer and it will play the audio of the video, but the video will remain black. Hitting play in the previewer also causes Unity to freeze, where it continues playing the audio until I ctrl alt dlt out of the program.

Thus far, I have been successful with converting the mp4's to ogg's prior to importing into Unity. This fixes all problems and allows the video to play with ease. The problem with that is the program I have been using to convert the video so far has a maximum starting file size of 2 gigs. With the tests I have been conducting so far, this works fine, but with the final video which will be over well over 2 gigs I am not sure what I will do.

My main question is - could this be an issue with Quicktime, Unity, or an error on my part? I have found two or three other threads with a similar question, but found no solution that worked for me thus far.

I appreciate your time. If I have improperly formatted this post or have posted in an incorrect location, please let me know. I am new to the community and appreciate all the advice I can get.