It is the end of the year again so i can fiddle with my linux HTPC once more. I am trying to decide on my video out solution for my linux HTPC. I'm trying to grasp the current state of video acceleration but it is rather confusing and i definitely need some help.
One thing i'd like to do is to use the open source drivers. Mostly out of principle, but also because i wouldn't like users of my projects using something else and not contributing with bug reports at least Also i have horror stories from using catalist/nvidia when needing to do dual head setup, so i'd really like to avoid those even if now i won't use those features, i dread the day i'd need to do anything with that kind of "support", and i think my time should help the open source drivers. e.g if everyone was using catalyst and praying for ATI, this would never happened
VDPAU is required for video out. Some places claim support for nvidia/intel/ati , others says it is never present in ATI and that i should look for xvba instead. is this now just semantic and all the video accell is called vdpau now? i did found this on Wolfgang Schup repo "WARNING: XVBA is deprecated as of october 2013, this PPA is not updated anymore! you should switch to the OSS radeon driver with vpdau support" 
cheapest card would be a GeForce GT 220. ~$50
(210 would have performance problems. also read that source for info on deinterlacing and other things which are not directly linked to VDPAU video decoding. i don't think i fully grasp it though.)
aparently 2d video accel on open source is better than proprietary, but power saving and 3d is much worse. I can't make much sense of the various drivers (r600, evergreen, etc), or get conclusive information. every amd/ati thread is derailled with people recommending nvidia... anyway, this all seems to be outdated. the end of 2013 status is that we should use the OSS driver! huray!
Intel is definitely the way to go if you just want something that works. The upcoming Broadwell GPU will be superb for video decoding and the hardware will have 4K video over HDMI 2.0 and DisplayPort 1.2 with MST for the upcoming 4K monitors that ship this year, beginning in April.