I'm making an intro for a youtube channel and i'm using videos that that person made. I downloaded them in mp4 format and they import into aftereffects fine. When i put them in the time line they dont play? When i add an HD video it works tho....?
Also how do you export with sound? Every time i export no sound goes through.
never mind about the sound thing, found it in FAQ
Regarding your issue with the MP4 files not playing well, I provide you with advice from Dave LaRonde at CreativeCOW.net:
Dave's Stock Answer #1:
If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, mp4, m2t, H.261 or H.264 -- you need to convert it to a different codec.
These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.
In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.
So convert it to a Quicktime movie with a PNG codec or your favorite lossless format and codec.