I use the 'Stock with CWM' kernel from here:
http://xdaforums.com/showthread.php?t=1515148
It's shouldn't make any difference for you since I believe yours and this kernel are the same except from the possibility to press Volume down at boot when the buttons light op and take a backup to the SD card (and other tools).
But you could try it - and the two other kernels in the link above. The kernel is flashed in fastboot mode (turn on, hold menu, plug USB in) with flashtool.
Another difference though could be that I'm actually running Arconium ICS 1.0 from the link above - that's the official Sony ROM but with some unnecessary bloatware stripped, I think. You can flash that after installing a kernel with CWM and using "Install zip from SD-card" but backup first so you can restore. I don't think you need to Wipe factory to defaults when using the ZIP file with the arconium ROM update - but I'm not sure.
None of my suggestions here should make a difference though... your videos shouldn't freeze since we're on the same hardware - and almost same software already, right?
Nothing I keep skipping the video recording, I'll try arconium 1.0
Many thanks for your interest.