The rules say you need 29.970? That is so dumb. I would use AssumeFPS to speed up your footage, there is no good way to dup frames from 24->29.970 at all.
If on the other hand you actually meant 23.976, which is VERY different to 24, then you can do 23.976 -> 29.970 by soft telecining your encode in x264. If you're using zarxguithingymabob, you can add a custom x264 flag to the batch file for it. I'm not too sure if the playback system would support it but it should. Make sure your x264 build is recent enough, and what you want to add is "--pulldown 32" and it should do magical things.






