The Jitter buffer interceptor doesn't respect the actual packet length

[braams]

Your environment.

• Version: 72c0be86db35deb9b0a7361063314923a3d9a68c

What did you do?

I'm trying to use jitter buffer interceptor.

What did you expect?

I expect to receive RTP packets as usual, but in correct order.

What happened?

I receive invalid RTP packets. The payload length is more than expected. The payload is filled by zeroes.

The reason

The interceptor tries to unmarshal the whole buffer and doesn't respect the actual packet length. https://github.com/pion/interceptor/blob/142f17f90b527434b62ce2fd92676e6e262cd807/pkg/jitterbuffer/receiver_interceptor.go#L77

It looks like we should replace packet.Unmarshal(buf) to packet.Unmarshal(buf[:n])