fixed bug in examples/rtp-forwarder where packet state is not properl…

[strangesast]

fixes corrupt RTP packet issue related to memory initialization/reset in examples/rtp-forwarder that causes frames to be distorted

[Sean-Der]

@strangesast are you able to reproduce this reliably?

Unmarshal should be safe to use like this! Possibly Padding isn't cleared properly? We might need a deeper fix in pion/rtp

[strangesast]

yes I get frames that are distorted like this with VP8 encoding. I had tried h.264 and get a different flavor of distortion.

when testing I noticed that I could get the demo to work with TrackRemote.ReadRTP but realized that was just a convenience wrapper around the same logic

it looks like there's an issue with how rtp.Packet.PaddingSize is set by Unmarshal. or at least that's the only value that differs between these approaches.

it's almost certainly related to this and this

[Sean-Der]

Ok great, I think we should fix that instead. Users have been copying/using this code so we should fix it deeper.

Would you mind making the change here to zero padding size? I believe that's the issue

[strangesast]

not at all. I've created this pr over there