Originally Posted by
Bob Pariseau 
Film is recorded at 24 frames per second. TV is recorded at 30 frames per second (displayed as 60fps in modern displays). The process of raising the frame rate of film to TV frame rates is known as "telecine". Ignoring some details, it is a pretty straightforward process which you've been seeing all your life -- any time you watched a move on broadcast TV. But because 24 does not go evenly into 30 there's a problem. Some portions of the film imagery will have to be held on screen slightly longer than other portions to make it work.
The result is what is known as "cadence judder" -- a very slight "ratcheting" of motion which the brain is quite good at ignoring, which is why they can get away with it.
But suppose instead of using a TV that put up 60 images a second you could make a TV that put up 48 or 72 or 96 frames a second -- some multiple of 24? Well in that case you could display you movie WITHOUT cadence judder!
Many modern TVs are able to accept 1080p/24 input (1920x1080 video frames 24 times a second) and automatically switch to a "refresh rate" which is a multiple of 24. Some of those TVs even manage to do that without screwing up!
Movies on Blu-ray are recorded on disc at 1080p/24. The player has the ability to output those at 1080p/24 or at 1080p/60 (i.e, the player applies the telecine). During the HDMI handshake, the TV (or AVR -- whichever is next in the HDMI cabling chain) tells the player whether it is willing TO ACCEPT 1080p/24 input.
1080p/24 OFF means the player takes 1080p/24 content and produces 1080p/60 output.
1080p/24 AUTO means the player takes 1080p/24 content and produces 1080p/24 output if the next device says it can accept that, otherwise 1080p/60
1080p/24 ON means the player takes 1080p/24 content and produces 1080p/24 output EVEN IF the next devices says it CAN'T accept that! This is for certain displays which are known to be able to accept 1080p/24 but which fail to publish that fact properly during the HDMI handshake.
Note that not all Blu-ray discs have 1080p/24 content. MOVIE discs have that. But Blu-ray programs produced using TV cameras are recorded on disc as 1080i/60. Such discs are never output by the player as 1080p/24, even if you have 1080p/24 ON selected. (If using 1080p output resolution, they are output as 1080p/60.)
Which brings us to standard DVDs. SD-DVDs of movies are recorded at 480i/60. That means that telecine HAS ALREADY BEEN APPLIED as part of making the "transfer" of the movie to the disc.
DVD 24p Conversion will attempt to extract the original 24 frames per second of the movie and output that as 1080p/24.
Obviously if you know your TV can't take 1080p/24, or doesn't "do the right thing" with it, there's no point in attempting DVD 24p Conversion.
But in addition you need to know that many SD-DVDs will not convert cleanly. First off, if the SD-DVD is of a program (perhaps a TV show episode) that was originally recorded at /60, then there IS no /24 stream to recover. Indeed you can't force /60 down to /24 in any useful fashion because there's no safe way to choose which portions of the moving video to discard.
And there are also true movie discs where DVD 24p Conversion won't produce good results because of the way the disc was recorded. Either the method of producing the master for the disc, or the editing of the master have left the original /24 stream in such confusion that the player will not be able to extract it cleanly.
In either case you will get "frame drop stutter" which is an easily noticed jerkiness of motion -- most obvious in pans because so much of the image is moving on screen.
If you know your AVR or TV can accept 1080p/24, then you may very well want to leave 1080p/24 AUTO set. However DVD 24p Conversion should be used judiciously. Use it with newer discs of newer movies to maximize the chance of a well recorded transfer. But at the first sign of frame drop stutter, go turn DVD 24p Conversion OFF (you can get into Setup and do that even while the movie is playing) and leave it off for the balance of the film.
Color Space and Deep Color refer to two different characteristics of the video data format presented on the HDMI cable.
RGB Color Space presents a Red, Green, and Blue value for each pixel. YCbCr Color space presents a gray scale brightness or luminance (the Y value) and two "Color Differences" (the CbCr values) which tell how to color that otherwise black and white pixel. Cb and Cr tell how much to add or subtract the Blue or Red coloration respectively. If you remove all the Blue and all the Red from a black and white pixel what results is a Green pixel. So these 3 components give you all the information for a pixel just like the 3 RGB components.
Why you would want to use one of the other is complicated. As a starting point, YCbCr 4:4:4 is the "default" format for HDMI connections, and the content on disc is also recorded in YCbCr (with added complications that I'll blithely pass over).
Meanwhile Deep Color refers to how many bits are used to represent each of the 3 components. Deep Color OFF means 8 bits per component (24 bits per pixel). The other choices are 10 bits per component (30 bits per pixel), and 12 bits per component (36 bits per pixel).
The data on disc is always 8 bits per component -- even for Blu-ray. That means 30 and 36 bit output don't really have true content data in those extra bits. They contain either padding zeroes or the result of rounding in the intermediate video processing.
The real problem for someone getting into this is that there is no pat answer to the question, "Well heck! Which combo is best?"
That's because AVRs and Displays have quirks (read "bugs") in there video processing implementations and because Displays really aren't physically capable of rendering 12 bits per component such that all the combos are distinguishable.
So the reality is that you either have to trust the recommendation of someone who's already tried this stuff with YOUR AVR and Display or you have to try it yourself and see if you can find a reason to prefer one combo over another.
If you check for a post by me in the Official OPPO BDP-93 Owner's Thread discussing "Ratatouille", Blu-ray, you'll find one suggested way of checking for whether there's a reason to prefer any of these combos over another.
--Bob
