[Libav-user] creating a basic live transcoder

[Luis Felipe Domínguez Vega]

Hi, I'm trying to create in C a basic live transcoder that use my NVidia 
for hardware transcoding. I trying to set the decoded frame PTS to my 
own because the source of the video is a UDP stream and can be 
restarted. So i want manage by myself the PTS value to avoid a restart 
of that value.

Really i dont found a good documentation about to how manage and create 
from 0 that PTS value.

Right now iw geting the frame from decoder, "modify ->pts", and send to 
encoder, only for testing i get a variable with "frame" counter that 
start at 0, tested this:

```
frame->pts = frameCounter++
```

Of course this, after video encoder completed, drop so many frames on 
the player (codec is h264 at input and output). So i think that i dont 
geting the idea behind pts.