How to achieve video resolutions above QCIF

I am running asterisk 1.8.10 (FreePBX). Videosupport=yes and allow=h.264 are enabled. I have video endpoints on both sides of the call that support 720p/30fps, but the best resolution I am able to achieve is QCIF. Understanding that Asterisk is a B2BUA and negotiates both legs of the call, what approaches can I take to achieve 720p resolution for video calls.

I am new to asterisk and appreciate your help. Google searches have not produced an answer.

Google searches won’t have produced results because this is a rare or unique requirement, and the solution almost certainly requires source code changes.

The SDP parameters for H.264 are described in RFC 3984. I don’t believe there is any generic way of adding parameters, so you will need custom source code to support them, either properly, or by forcing them to the same values for all H.264 negotiations.

What do you have for maxcallbitrate ?

Thor, thanks for your reply. I have maxcallbitrate=1152. The actual call takes place at roughly 1152kbit/s total (audio and video combined), however the video negotiated is H264, 176x144 at 15 frames per second.

Both end points in the call can support, and attempt to negotiate for, H.264, 1280x720 at 30 frames per second. If I unregister the end points from Asterisk and make the call directly, I achieve the resolution and frame rate desired.

Since Asterisk acts as a B2BUA, it is clearly negotiating the session description with each leg. How can I get Asterisk to negotiate for higher quality H264 video?

You probably need a higher number for maxcallbitrate

The two end points make a 720p video call at 1152kbit/s. If I unregister the end points from Asterisk, I get a 720p video call at 1152kbit/s. Making no other changes to the end point configuration will result in a 176x144 call at 1152kbit/s when registered to Asterisk.