The default gentoo ebuild disables all time the support for crystalhd. Could you enable this by default or enable a use flag for this?
"--disable-crystalhd" change to "--enable-crystalhd" or $(use_enable crystalhd)
This enable crystalhd, it would be possible to use the video accelerator.
media-tv/mythtv, for example, has such use flag called crystalhd
Unfortunately, libcrystalhd required to enable that use flag is not in portage, yet. So this use flag cannot be enabled until some volunteer starts to maintain that package.