RenaKunisaki

>>> What's the correct way to determine a frame's play timestamp (as UNIX timestamp) in libav?

<think>
Okay, I need to figure out how to get the play timestamp of each frame as a UNIX timestamp using libav. Hmm, I remember that libav has some 
structures and functions for handling frames and streams.

So first, I think about the steps involved. Each frame has its own presentation time, right? In libav, frames are part of a stream context, so 
maybe I need to access each stream's parameters.

I recall there's an AVStream struct which contains information about the stream, including a timebase. The timebase is used to convert