Which is better for HDTV? 120 Hz or 24 FPS?

[Daylightdon]

Hi Chris, Which is better 120Hz or 24fps?
You changed my mind on that other Panasonic.
Because of my previous experience with the reliability of Panasonic, that will be my brand of choice.

I'll probably go Plasma again though, but it will be 50 inches and not over 32.5 inches high w/stand.

I'm currently watching 42".

[MrBoylan]

Hi Chris, Which is better 120Hz or 24fps?

Hey, Don... moving these posts as I think this discussion merits its own thread. Comparing 120 Hz to 24 FPS is really apples vs. oranges. 120 Hz processing is something you see pretty much exclusively on LCDs and it was developed specifically to improve traditional LCD TVs' poor reproduction of moving images (motion smear). By doubling the display rate from 60 Hz to 120 Hz, either using black frame insertion or motion interpolation, they can clean up the reproduction of moving images. And 120 Hz processing typically does work on the 60 Hz signal *not* directly on the 24 FPS source. This means you can still have motion "judder" because the 24FPS original source (most movies are filmed at 24 FPS) has to be unevenly mapped into 60 FPS. 24 does not go into 60 an even number of times, which means some frames are repeated twice, and some are repeated 3 times, giving the motion a slightly jerky unnatural look.

Plasmas don't really suffer from as much image smear as LCD so 120 Hz is not necessary. The Panasonic plasma TVs run with a 480 Hz or 600 Hz "sub-field drive" which is one of the reasons they reproduce motion so well.

Now as far as 24 FPS (frames per second) support, some LCD TVs, projectors, plasma TVs, etc. do support a native 24 FPS input signal, typically 1080p/24FPS (aka "1080/24p" or "1080p/24") from a Blu-ray player or other similar source. But even TVs that support a 1080/24p *input* may (and usually do) convert this internally to 1080/60p for display, so you will still get some motion judder. Some of the higher end plasma and LCD models (as well as some home front projectors) take the native 1080/24p input signal and display it directly (with NO conversion to 60Hz) at some multiple of 24Hz. On plasmas, this is usually done at 48 Hz, 72 Hz or 96 Hz. On LCDs, it is typically done at 120 Hz or 240 Hz.

Movie theaters (traditional film-based ones, anyway) work the same way, displaying 24 FPS movies typically at 2X (48 Hz) or 3X (72Hz). They simply repeat the same film frame two or three times very quickly in order to minimize flicker (which is different from judder). Flicker is the blinking from light to dark that some find distracting. The 2008 Panasonic models (PZ800 series) supported 24FPS material natively at 48Hz. The upcoming V10 and Z1 Panasonic TVs will support 24FPS material at 96 Hz (4X normal rate) so they should maintain all of the advantages of a native 24FPS mode with no visible flicker.

This feature (native 24p support) goes by different names, such as Cinematic Playback, or "5:5" conversion (on 120 Hz sets), or 24 FPS native support. It's not always easy to find out if a set supports it, but usually in either the manual or the marketing material you'll find some reference to it.

You changed my mind on that other Panasonic.
Because of my previous experience with the reliability of Panasonic, that will be my brand of choice.

I've had good luck with Panasonic gear too.

I'll probably go Plasma again though, but it will be 50 inches and not over 32.5 inches high w/stand.

I'm currently watching 42".

The TC-P50V10 is 32.2" high with stand so it looks like you're golden! And of course, it's THX certified, and has native 24p Cinematic Playback mode (96 Hz). So now you just have to wait for them to start shipping...

-CB

[Daylightdon]

Hey Thanks TEACH! You are GREAT!

[rgs]

MrBoylan,

I wonder if you know if the Benq W500 supports native 24P. I've looked through the manual but can't seem to find this referenced as such.

Thanks,
Richard

[MrBoylan]

MrBoylan,

I wonder if you know if the Benq W500 supports native 24P. I've looked through the manual but can't seem to find this referenced as such.

Thanks,
Richard

From what I can tell, it does support a 1080p/24 input, but it has no native 24p mode so there is no real benefit to having the 24p input support. I still converts it to 60p for display. Native 24p features are actually pretty rare in projectors and you usually only start to see them in the more expensive models.

-CB