24fps options

[mattjax05]

Hi everyone

What are my options if my LCD does not accept very well 24fps and I want to watch a blu-ray. Can blu-ray players output at 50hertz, does the discs store 25fps? Or do I just put up with any descrepancies! By the way my tv is a Samsung LE40M87BDX.

Thanks, Matt

 

[mattjax05]

Can anyone advise please?

Thanks, Matt

 

[Messiah]

The TV will accept the signal and converts it onboard as far as I can remember when I bought mine so it should be fine.

 

[Anonymous]

Hi,

Without knowing which LCD & blu ray player you have I would suggest the following:

If your LCD TV does not accept 24fps, your blu ray player should not let you select this as an output option.

If it does, but it does not hadle it too well, i.e. it judders, just go into the player setup menu & turn this option off, it just means that the picture & sound runs about 6% faster than director intended / filmed it at.

Hope this helps

 

[Anonymous]

All LCD TVs accept 60Hz, which is what the 24fps content on the discs will be converted to if you don't tell the player you have a 24Hz TV (some players aren't clever enough to tell if your display can accept 24Hz, so you get a blank/messed up screen if you try and force it). This is done using 2-3 pulldown, but you'll see some image judder as a result. Technically it's actually 23.976Hz into 59.94Hz on the vast majority of discs (only seen a handful encoded at exactly 24Hz).

Contrary to what's been said above, there is no speed up with HD film material regardless of whether you use 24Hz or 60Hz. Players do not convert to 50Hz and apply real-time speed/pitch correction to the soundtrack! HD is neither PAL nor NTSC - the film's runtime and audio speed/pitch will be preserved with pulldown (and even if it wasn't it's 4% not 6%).

As it happens, a lot of TV accept 24Hz input but convert it to 60Hz. The more advanced sets refresh at a multiple of 24 (usually 72Hz or 120Hz) and use pulldown to display pans smoothly (relatively speaking).

 

[GazzyP]

Just to try and get a handle on this: What is actually on the disc? Is it 24fps or 60/50fps?? And does it vary depending if the content is filmed on Film or Video? In which case surely something filmed on video at 50/60fps is going to have smoother motion than film at 24fps?

And if there is no difference in speed what is the benefit of 24fps?

Also what happens with a TV which has 100hz or even 200hz? That seems like a lot of processing to me.

 

[Anonymous]

This is an interesting question about 24fps. Because when I asked this question on the What HiFi Forum some time ago I was complaining about the stuttering because my LCD will not support 24fps. I explained that the Panasonic DMP-BD30 was able to switch the function off but it made no difference. I recall Clare telling me that was because the BD output was 24 fps from the BD disc and nothing would make a difference? So ...why does the DMP-BD30 let you do it if you can't deactivate it in the background.? Hmmm?

 

[Anonymous]

I'll try and break it down.

Film content is usually (i.e. 99.9% of the time in my experience) stored on disc at 23.976fps, rather than at an exact 24fps. This is for technical reasons to do with the NTSC 60Hz, which is in reality 59.94Hz. Most people simply round up these numbers for convenience.

Most TVs are incapable of accepting a 24Hz input. In this case the player takes the 24Hz content and repeats frames to go to 60Hz, using the 2-3 sequence that's been used in DVDs for years. The process is called pulldown. Some TVs will accept a 24Hz signal, but they then convert that internally to 60Hz. In either of these cases you will see excessive judder on camera movements.

If your TV supports 24Hz material at a multiple of 24 (i.e. 72, 96, 120), then you will see a noticeably smoother image (not completely smooth, as there are still only 24 frames, they're just played in sequence rather than being repeated out of order). A lot of the newer, high end sets do this.

There's a Wikipedia artcile that explains in in more detail here : http://en.wikipedia.org/wiki/Telecine

Video content is normally laid to disc at its native framerate. While it is smoother than film, that's because it has more frames to begin with. Encoding a 24fps film (nearly all films are shot at 24fps) at 60fps wouldn't make it smoother, because the 60 frames would still only be made up of the original 24 frames repeated (which is how pulldown works).

 

[GazzyP]

Thanks - that realy clears this up, and I suppose explains why music concerts, which I would assume are shot on video appear to be far smoother. Why cant they use a higher frame rate for film? Wouldnt that be the ultimate solution, rather than slowing down the rate the TV shows?

 

[Anonymous]

Cost is a major factor. Almost every camera and projector in the world uses 24fps. Plus, if stuff was shot at 60fps, you'd lose some of the dream-like quality associated with film.