srtpenc/srtpdec force application/x-srtp even when encryption disabled

Submitted by David Woodhouse

Link to original bug (#793704)

Description

Created attachment 368731
Use application/x-rtp caps when decryption is disabled

See https://bugs.freedesktop.org/show_bug.cgi?id=105193

The FarStream fsrtpconference creates srtpenc/srtpdec elements unconditionally. If no encryption is negotiated, they pass RTP packets through with no effect. But the negotiated caps are still application/x-srtp, not application/x-rtp which is what's actually being sent.

This works OK when the transmitter is some UDP network thing which accepts anything and doesn't care.

However, in my case I do care, because I'm connecting fsrtpconference up to my own RTP depayload which really does need it to be correctly labelled as application/x-rtp.

Here's a half-baked attempt at making it work, which might work for srtpenc but has certainly broken srtpdec.

Patch 368731, "Use application/x-rtp caps when decryption is disabled":
srtp-allow-rtp.patch

Version: 1.x