SD then HD causes hang

[jmxp]

Has anyone experienced this problem:

Fresh reboot of front end -> Launch HD content -> Plays fine

Launch SD content -> Plays fine -> Launch HD content -> front end slows to crawl - system becomes non-responsive. Only fix is to reboot.

Reboot front end -> HD content plays fine again.

[elaw]

Is this watching live TV or previously-recorded material?

If it's live TV, could be a driver problem with one or both capture cards. If it's existing files or both, could be a codec problem.

I had an issue vaugely similar to this (the second case, trouble playing existing files) with one of my clients, it turned out to be a bad version of AC3filter. I think I had 1.09 installed, upgraded it to 1.11 and it now works perfectly!

Note that in my case the problem was audio-related, even though your first instinct may be to blame the video. Most SD material has MPEG audio, and most HD material has AC3 audio. So you may be using different codecs, or your sound card may be getting upset with AC3 audio (possibly a driver problem).