AVS Forum Special Member
Join Date: Jan 2003
Location: Portland, Oregon, USA
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For DVD material there are several considerations. [EDIT] For many DVDs "24 Hertz" material has been edited and compressed as "480i" (or 576i) material. This short-cut taken by many studios can be the cause of "Bad-edits" which can in-turn cause issues with deinterlacing.
Some DVDs use a flag embedded in the material that tells the player how to convert the interlaced fields back to progressive. This can help, but one of the main encoding chips used for encoding many of the "pre-Bluray" DVDs had an error in the generation of this flag which could cause problems.
So, what's the best output mode to the Radiance for DVDs?
If a DVD is encoded as 480p24 (or 576p25), then if the player can output at 480p24 (or 576p25), then that would be the best option. I don't know if any players will do this, and I am not sure the Radiance has even been tested with this input rate. Since the Radiance NoRing(TM) scaling is best, and there may be some inverse-telecine issues in the player, we do NOT recommend outputting DVDs at 1080p24 [EDIT] from the player.
So the best option is to either output to the Radiance as 480p60 (or 576p50) and have more judder, or output as 480i (or 576i) and let the Radiance deinterlace and pull out the cadence so it can then output as 24p (or 60p, or 25p, or 50p as appropriate) to your display/projector.
If you are sending the Radiance 24p material as 480i (or 25p material as 576i), you should select "FILM" mode for deinterlacing in the Radiance. The issue is that in some frames there is not enough contrast for the deinterlacer to be certain of the existence of a cadence and the GF9450 deinterlacer will immediately revert to video mode, which will not provide the best image quality for progressive source encoded as interlace. In FILM mode deinterlacing the Radiance can override the output of the GF9450 deinterlacer and instead use its own cadence history to keep the inverse-telecine to progressive conversion working properly, and so correctly reconstruct each frame.
Also, for 24p (or 25p) source sent to the Radiance as interlace, you may want to turn on Genlock. This will insure that no frames are dropped and no frames are doubled. For Film source at 24 or 25 fps this can be noticeable. NOTE: For cable/satellite "video" source material, we generally recommend Genlock be left off since it significantly increases the switching time between inputs or for input resolution changes.