So I dynamic link's a clip from Premiere and the Comp is the duration of the clip. Well I want to track something so I double click the comp and opens up the entire source file. How do I see the comp duration in the source file? It's driving me mad. Even when I use Mocha AE and export shape data, for example, I dunno what exact frame I need to place the track data on. Does anyone know the answer?
That's just how it works. You need to trim your clips in Premiere and generate a new master clip from it, only containing the rendered part.
It sounds to me like you are new to AE and tracking and have little experience with Mocha. When you create a comp from a clip in Premiere Pro the clip is trimmed. There is no need to open up the clip to track it in AE or in Mocha. Just select the clip and go to the tracking workspace and select the clip as the source or select the clip in the timeline and select Track in Mocha. Inside mocha there is an option to show just the in and out points (check Mocha help).
Most of the time I only need to track a portion of the shot so I'll split the shot in the timeline so that only the frames that need tracking are on that layer. This saves a bunch of time. Maybe this will help. It shows how I converted an MP4 to usable footage for tracking in Mocha AE and then isolated just the part of the shots that I needed to use. I did this tutorial for a user on this forum and used their original footage. Enjoy: