Theora SIP video freezes with rapid movement on Ekiga

One heck of a bizarre (and serious) bug seemingly afflicting Ekiga 3.2.7, at least on Windows.

The following video (.ogg format) was captured on an OpenIndiana oi_147 machine, running Ekiga 3.2.7. It is receiving a call from a Windows 7 (64 bit) machine, also running Ekiga 3.2.7. Theora is the only enabled video codec at both ends. Both machines have public IP addresses, and are connected to a corporate LAN.

The video below (click to play) illustrates how if rapid movement is made in front of the webcam attached to the Windows machine during the call, video can be made to freeze. Note that the application and call continues to run – just that video remains frozen.

Theora freezing on Ekiga for Windows

At the very beginning of the video we can see an incoming call from the Windows client being accepted, followed by a stable connection with good video quality. In this example, I have chosen to deliberately freeze the video 25 seconds into the call. At around 23 seconds in, I make a rapid hand movement in front of the Windows machine’s webcam; the video freezes almost immediately. The camera is then zoomed in to show that the call is in fact still active (audio for example is fine). The call is then terminated.


UPDATE:
The freezing is much, much more easy to induce with low “Maximum video bitrate” settings in the Ekiga client preferences. All my tweaking involved adjusting the bitrate, while leaving the “Picture Quality” slider parked at maximum frame rate (i.e. all the way to the right).

1) With “Maximum video bitrate” set to 64Kb/s, the video will freeze with very slight movement; more often than not it will freeze as soon as the call is connected.

2) With “Maximum video bitrate” set to 1024Kb/s, I can reproduce the behaviour exhibited in my original video above, as that was what the settings were when the video was recorded.

3) With “Maximum video bitrate” set to a high number, e.g. 3072Kb/s, then it becomes very difficult to freeze the video deliberately; lots of flailing around in front of the camera to induce a freeze (it can still be done however).

Settings above ~4000Kb/s seem to revert to the behaviour observed when set to ~1000Kb/s however.

I have also reproduced this issue on Ekiga running on Windows XP Professional SP3.

 

Leave a comment if you have a firm idea of what’s going on here.

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