I'm completely new to video/audio formats, containers, and protocols. However, I have to figure out how to decode a bitstream that contains audio and video. I do not know the transport protocol, container format, or codecs used -- but I have been able to deduce a few things:

  • It's not RTP
  • It's over UDP on port 443
  • Audio and video are in datagrams
  • audio datagram payloads are always 76 bytes in length, and there are about 42 of them a second.
  • video datagram payloads are a maximum of 536 bytes, average is around 500 bytes, and there are about 62 of them a second.

How should I even begin to try to decode it?

  • Did you try decoding it with ffmpeg? It supports UDP as input.
    – LordNeckbeard
    Jul 13, 2012 at 20:51

1 Answer 1


Capture a chunk in Wireshark and then chose "decode as" and keep picking different A/V formats and see if any of them work. If none of that helps, upload a 100 kbyte wireshark pcap file and link to it here and I'll take a look.

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