I am trying Final Cut Pro X. When I import video files (containing audio) into AE rendered from FCP X using either h.264 or ProRes422 there is no audio. If I play the same file just in the quicktime player there is audio.
Just to check myself and make sure that I wasn't missing any "switches" check boxes etc, I rendered the same video file from FCP X with the animation codec. Worked like a charm in AE CS5.5
I'm sorry if this goes unsaid, but are you talking about playback in the AE timeline, or in the export? If it is playback, what happens when you select "audio from here forward" from the right click menu in the timeline?
If export; do you have it set to export with audio?