RivaTV

The RivaTV project "aims to provide driver support for nVidia based graphics cards with video-in feature and some of the video capture chips that come on such cards. The driver also activates tuner and audio support provided by the V4L project."

A list of supported cards is available here and here ... with the latter likely the more inclusive source of the two.

Drawbacks
RivaTV:

• is adherent to the V4L1 API, and not the now widely used V4L2
• provides, in the case of some decoders, support that is likely quite dated and would be much better supported by some V4L supplied/produced drivers instead
• makes clear warning that it does not offer support for a number of "Personal Cinema" cards (i.e. those based on the 7174HL decoder chipset).
• does not appear to work with any recent Nvidia binary driver since the 5x.xx series....there is an intricate relationship between the card's capture facilities and the Nvidia GPU registers. Unfortunately, modern versions of the Nvidia X driver and the RivaTV drivers can not both have concurrent access to these GPU registers without creating problems.
• provides tuner support based on ancient code (i.e bttv version 0.8 .... in other words, well predating V4L)
• has problems with framebuffer consoles

The bottom line is that RivaTV is in dire need of some modernization. However, other than periodic commits to its CVS that re-establish/provide the ability to compile the RivaTV drivers on recent kernels, the project currently does not appear to have any sort of continued development. A fact that is most unfortunate for owners of Nvidia based graphics cards sporting video in capabilities.