There are many things that could be the issue. For starters make sure you have the composition or timeline selected when you export. Also make sure that your work area spans the part of the timeline that you want to export.
Try exporting with Media Encoder but add a preset such as Youtube 1080P and render - see if that clears this issue up. When you playback your video use an updated Quicktime player.
Yes, the composition is selected and the work area spans the correct timeline - I know this because the right audio is exported into the video and it's the correct length, just missing the video portion.
I exported in Media Encoder, but I cannot use the presets because I'm trying to export to 16:10 (the native aspect ratio of our projector) and all of the presets seem to be 16:9.
I forgot to freeze the rotoscoping on a few of the exports, so I froze it and am currently retrying the export. Hopefully that will work
That's a very odd aspect ratio for a projector. Extremely odd.
What other files play back successfully with this projector?
What are you using as a playback device for successful playback?
What are the horizontal & vertical dimensions of the file you're trying to create in AE?
We haven't tried the video on the projector yet, it's not exporting correctly and the video isn't showing up in the export while testing it on our computer. We have tested other .mp4 videos prior to rotoscoping (those were exported from premiere pro but not yet put through the editing in After Effects) and those videos play on the computer as well as on the projector.
The dimensions are 1920 X 1200.
I take it the mp4's exported from PP are 1920x1080, and they play successfully AND without distortion, correct?
Certain media containers and codecs only allow a finite set of horizontal & vertical dimensions.... mp4 among them. This could be the source of your problems if you're actually trying to create 1920x1200 files.
If we change it back to 16:9 (the 1920x1080 dimensions the video was originally), it should work again? We can probably play the videos on the projector at 16:9 and test to see if there are any issues with that.
It worked with the video! Thank you so much for your help. We'll make it work with the projector as well.