Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Ready to go Blu-Ray. Anything I should be aware of?

ActionableMango said:
The vast majority of BDs are film encoded at 1080p/24, the latter part meaning 24 frames per second. LCD computer monitors and most inexpensive TVs display at 60 frames per second. 24fps does not divide nicely into 60fps.

At 60fps, every other frame is played twice (for 24 of the 60fps), and the other half of the frames are played three times (for 36 of the 60). 24+36 equals 60. The duplication and triplication of frames are referred to as 3:2 pulldown.

This is surprisingly not noticeable in most cases, but is very evident usually when there is a ticker or panning. Even complete "video noobs"* will notice it during the credits rolling at the end. Notice how jerky it is? It should be smooth.

Your Mac LCD is no doubt set to 60fps so you are hopefully getting 3:2 pulldown, which is the best way of dealing with the FPS mismatch. There are also worse ways of handling it, depending on the content, the player, and the OS video driver. Those will be painfully obvious though, like a constant flicker. I used to see that when playing imported PAL DVDs (50fps) on the computer.

Capable BD players will recognize 24fps and can output it at 24 fps. Capable TVs will then play it at a direct multiple of 24, such as 72 or 120fps. This way there is no uneven duplication of frames and no judder.

All of this applies to film. Material recorded for broadcast TV/cable/SAT is 60Hz.

* My GF can't even tell the difference between DVD and Blu-ray, but she sure notices judder caused by framerate mismatch.
Click to expand...

Thank you for the detailed explanation. I think I actually do notice that jitter most of the time if I look for it, but it's so subtle it doesn't really matter, and it doesn't scream out at me.

When you convert 24fps to 29.97fps, so there are only ~30 frames in each second and every third frame is played twice, that is a noticeable and annoying jitter. This 3:2 pulldown thing is happening within a scheme of 60 frames passing every second, so obviously it's much faster and harder to notice.

Apple has 16:9'd their newer displays... does this mean they have better support for watching films? Or is everything still 60Hz?
 
I have the 30" ACD.. I was asking if the new 27" 1440p displays are 60Hz, or if at least they have a built in technology that makes them play 24p seamlessly.
 
Until streaming supports audio commentaries and all the other thing's that comes on Blu-Rays/DVD, I will never just go for streaming.

It's certain shows and movies I buy Blu-Ray for and others I just get DVD but either way I can't just rely on Netflix, Itunes, etc...
 
I don't know, but I doubt it. LCD monitors seem to be overwhelmingly 60Hz. I seem to remember a long time ago some that did 75Hz, but I'm not sure what that was for.
 
Blu-ray made running an inaugural film festival very easy for me. I had several blocks of films to show in one to two hour segments of time, and burning the entire assortment of films onto single discs for projection through an HD projector at the theatre made my life very easy, as well as looking absolutely amazing on the giant screen. If we had scraped up an additional $3600, we could have rented three purpose-built laptops with RAID drives and special projection software, but buying 40 BD-R discs for about $1 each was just insanely cheap, so discs > files in this case. We already had three Blu-ray players as well, so it made a lot of sense and worked perfectly during the film festival. Robert Forster was there, and told us he was proud of what we were doing, which was pretty cool.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back