Just thought I would share my experiences with using VDPAU to decode MPEG2 1080i. I am running 8.2.0 which (as of this writing) has the latest Linux nVidia drivers. 1080i MPEG2 is what you get from live TV (OTA or Cable). I am using a GTX 1050 which is relatively modern and powerful. VDPAU acceleration did a relatively poor job of decoding and deinterlacing MPEG2 1080i content. The integrated AMD GPU in the AMD processor in my HTPC did a much better job using VAAPI. So if you are viewing mainly MPEG2 1080i content, I would stay away from nVidia cards, I don't have an external AMD card to see if that is better than the integrated AMD GPU.
Other HTPC build details:
ASRock A88M-ITX/AC R2.0 Socket FM2+/ AMD A88X/ DDR3/ SATA3&USB3.0 motherboard
AMD A10-Series APU Processor with Radeon R7 Graphics (A10-7860K)