I'm using the newest binaries for kdenlive and mlt from sunab-svn on Kubuntu 12.10, x86-64.

When I stablize a clip which is 1080p I get a .mlt file for which kdenlive constantly creates a broken proxy: the proxy clip is framed by a big black frame. Creation of proxies for ordinary clips works as expected.

This is how the proxy clip looks like.

Strange, I cannot reproduce. Did you stabilze the clips using the same HD 1080p profile? Can you copy / paste here the first lines of one of your "Stabilized" .mlt clip (I am mostly interested in what is in the "profile" tag.
I would also like to see your proxy settings (you can find them with the "info" button near proxy encoding profile in the "Project > Project Settings" dialog.

One thing I noticed in the meantime and that may be of importance: when I have proxies enabled, then the proxy clip gets stabilized. So what I did was to switch off the proxy for this particular original clip, then stabilized it, and only used that without proxing it any further.

So, the .mlt file seems to be clean:
----
<?xml version="1.0" encoding="utf-8"?>
<mlt LC_NUMERIC="de_DE.UTF-8" version="0.8.8" root="/home/harald" title=""Stabilised"">
<profile description="automatic" width="2704" height="1524" progressive="1" sample_aspect_num="1" sample_aspect_den="1" display_aspect_num="2704" display_aspect_den="1524" frame_rate_num="25" frame_rate_den="1" colorspace="709"/>
...
----

I'm using a modified proxy encoding profile that is defined as follows:
----
-f mpegts -acodec libmp3lame -ac 2 -ab 128k -ar 48000 -vcodec mpeg2video -g 5 -deinterlace -s 1080x720 -vb 4000k
----

Thanks for the feedback & troubleshooting!

>Did you stabilze the clips using the same HD 1080p profile?

I'm not exactly clear what you are referring to here: I set the project profile to 1080p/25fps. This particular clip is in 2700x1520, as this is the material that the new GoPro HD Hero3 Black is able to produce; very convenient ... but I disgress.

Is there a way to stabilize a clip using a different profile? I'm not aware of being able to do so.

Could this be a problem kdenlive not properly taking into account that the original clip is of a different size than the project?

Diveo - are you using vstab or transcode version of stabilize? I am trying to figure out if anyone else gets crashing of the transcode stablise version. When I run it with 0.9.4 the job runs to about 10% and then kdenlive crashes.

I'm using transcode since I never got satisfying results with vstab. With transcode it still not good, but better than vstab... But I don't experience any crashes so far.

Ok, I reproduced. Happens only on some locale (when using a comma as decimal separator). I am investigating...

Fixed in git now.

Many thanks!