Sunday, December 7, 2008

is a source running at 24 fps?

The PureCinema film mode can reverse telecine 24 fps (frame per second) film material and display it at a native 72 Hz. A Blu-ray player can transmit a movie over HDMI at its original 24 fps and have a Kuro display this at 72 Hz. This is great and it eliminates the effect of 3:2 pull-down induced film judder. So how can it be determined if a Kuro is being fed a source at a 24 fps rate?

The Sony BDP-S350 Blu-ray player has a "24P" blue LED that lights up when 24 fps material is being output. This is a great feature since it is rather tricky to correctly configure the S350 for 24P output. Unfortunately there is not an easy way to query a Kuro's refresh rate. Other than observing the smoothness of motion and pans, there is no way to tell if PureCinema is actively performing reverse telecine. Switching an HDMI source to be a PC input is a trick that will report the input frame rate.

Here are the steps to check the refresh rate of an HDMI source:
  1. Select HDMI input
  2. Press Home Menu
  3. Enter Setup
  4. Enter Option
  5. Enter HDMI Input
  6. Select PC from the Signal Type submenu
  7. Exit menu
  8. Press Display to see the refresh rate
  9. go back to step #1 and change Signal Type back to Video
Unless your source is a PC you probably won't want to keep your HDMI in PC mode since it has a number of picture ramifications that are not good for general TV and film viewing. It would be a really nice feature if Pioneer gave the Kuro a special control panel screen that displayed internal information like frame rate, 720p or 1080i resolution, MPEG2 bit rate, AC3 channels and bit rate, and full PSIP information.


Greg said...

I actually have a Sony BDP-S350 Blu-ray player, so I know when the BDP is outputting 24 fps. However, I can't seem to see a difference between the PureCinema modes Off and Advance, and I guess there's no way to tell what the current refresh rate of the TV is, i.e., if it's refreshing at 72 Hz. As you said, it sure WOULD be a great thing to be able see things like that.

Erik said...

Sweet Lord Almighty, thank you! I have been killing myself over this issue. I have a new Panasonic BD player and it gives me a 24p icon on-screen, but I was always wondering about the 151FD (which I scored at Tweeter's bankruptcy fire sale!). Thanks a ton for the tip.

Erik said...

I find watching the scrolling credits at the end of a movie to be a great test to see the effects of 24p. With 3:2 pull-down (60 Hz) you'll see a slight jerkiness of the motion a couple times a second. With 24p the scrolling motion will be perfectly smooth.