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ATI and nVidia Crush High-End DVD Players
An anonymous reader writes "Hardware.Info compared the video quality of ATI and nVidia video cards containing Avivo / PureVideo technology with 12 stand alone DVD players, varying in price from $200 to over $2000. The conclusion? 'There is no need to invest $2000 or more in a high-end DVD player. A PC with a recent graphics card will produce a much better result for a lot less money. When looking at the final scores of the HQV test, both ATI and nVidia graphics cards perform a lot better than any DVD player we have tested. We would go as far as to say to get rid of your DVD player and connect a media centre PC to your LCD television!'"
The big problem is that the video output from these consumer video card devices is never synced properly to the source video rate. The "cadence" tests in this article are worthless because no encoding-based pulldown is happening since it's being rendered progressively. The pulldown that's happening instead is taking the progressive source (or god forbid the interlaced source) and displaying it on whatever frame rate your display happens to be set to.
Working with film, this means 24fps. If your display is 70fps, 75fps, etc. that means some ugly pulldown is in store.
What gets even worse, however, is if you use the video output feature of your card in a HTPC setup -- you wind up having it go through ANOTHER PULLDOWN to 29.97fps (NTSC) or 25fps (PAL) FROM THE PULLDOWN YOU DID BEFORE. Even worse it's resampled and scaled for this output.
This is pretty apparent in pans in movies and such -- the pans are never quite smooth exactly.
Also since sound and video are usually totally unsynced subsystems in a HTPC, the audio is often slightly out of sync with the video. This causes an occasional audio or video skip (depending on what the playback software recognizes as canonical sync). For short clips this usually doesn't happen, but the skip will often happen over the course of a movie. If it's syncing to audio, the frameskip/delay is usually not noticeable because it gets lost in all the pulldown issues mentioned earlier.
While it's possible to make a HTPC setup that syncs the video properly to avoid these issues, I've never seen a HTPC setup do it right. I've seen embedded Linux and WinCE devices do it correctly, using custom code to ensure proper video syncing.
Standalone DVD players, even most cheap ones, get everything synced properly to a reference pulldown (29.97 or 25 fps, progressive if supported). Framerate and audio sync is always correct, to the nearest level capable of the pulldown.
It's a shame, because modern LCD/Plasma displays with digital inputs should theoretically be able to handle real 24fps input for film sources, for instance, which is something current DVD players don't do. Try getting your HTPC to output 24Hz and getting your media player, going through all the video and audio APIs of your OS, to sync every frame and every audio sample exactly to it. =P It simply can't be done -- you have to code to the metal.
(In studio environments video editing PCs actually have professional video/audio cards that have custom APIs and synced internal clocks to be able to ensure perfect framerates and audio sync and to make sure playback is timed properly on them. I know someone who's built themselves a HTPC with gear like this and it works great.)