I'm writing an app where I generate thumbnails from mms streams using external ffmpeg tool.

I have two questions:

1. Is there a way to generate thumbnails from mms stream using built in functions?

2. I need to refresh the thumbnail on regular basis, however because the thumbnails are cached, it always shows the first cached thumbnail image. Is there a way to overwrite this? Where is the cached thumbnail stored? I couldn't find the images in the directory structure where other thumbnails are cached:

~/.boxee/UserData/profiles/<username>/Thumbnails/Video


Thanks in advance,