24fps vs. 60fps on Blu-ray

[DaDude]

Let me first state that my TV?s resolution is 1366x768. I notice on my Blu-ray player, there is an option to have movies play at 24fps. It?s set to 60fps, by default. I?ve read everywhere on several sites that if your TV is capable of accepting 24fps, I should use that feature as it will give better results. Well, on my TV, it seems to be the opposite. If I set it to 24fps, my TV accepts it, but I notice that there?s a little more noticeable motion blur present, not to mention that the input lag is slightly longer. On 60fps, there is less motion blur and the input lag isn?t as bad.

Why exactly am I not getting the best results from 24fps? Is it because 24fps only works well with 1080p TVs?

[Dead_Monkey]

Let me first state that my TV?s resolution is 1366x768. I notice on my Blu-ray player, there is an option to have movies play at 24fps. It?s set to 60fps, by default. I?ve read everywhere on several sites that if your TV is capable of accepting 24fps, I should use that feature as it will give better results. Well, on my TV, it seems to be the opposite. If I set it to 24fps, my TV accepts it, but I notice that there?s a little more noticeable motion blur present, not to mention that the input lag is slightly longer. On 60fps, there is less motion blur and the input lag isn?t as bad.

Why exactly am I not getting the best results from 24fps? Is it because 24fps only works well with 1080p TVs?

Your display is doing some sort of image processing on the 24fps signal, possibly combining frames instead of doing a regular pulldown (24 frames does not evenly go into 60 frames, so typically there will be what is called a 2:3 pulldown, where for each three frames in the source, two of those frames will display for two refreshes, while the third will display for three refreshes). Since you're noticing blur, your display may be blending frames for a more "fluid" effect.

You might be able to disable the processing on your display, but obviously if the problem is that you're experiencing pain in your eye whenever you drink tea, you should probably just take the spoon out first (swap your player back to 60 frame output).

[EmuZombie Veteran]

In my experience, it doesn't matter what anyone else says or what the common agreement is. Use whatever settings look best to you. Everyone's hardware is different and everyone's eyes are different. However I agree with what was stated above as an explanation.

[FiB3R]

"if the problem is that you're experiencing pain in your eye whenever you drink tea, you should probably just take the spoon out first"

LOL ****ing classic :)

[HawkMan]

Your display is doing some sort of image processing on the 24fps signal, possibly combining frames instead of doing a regular pulldown (24 frames does not evenly go into 60 frames, so typically there will be what is called a 2:3 pulldown, where for each three frames in the source, two of those frames will display for two refreshes, while the third will display for three refreshes). Since you're noticing blur, your display may be blending frames for a more "fluid" effect.

You might be able to disable the processing on your display, but obviously if the problem is that you're experiencing pain in your eye whenever you drink tea, you should probably just take the spoon out first (swap your player back to 60 frame output).

If the TV has "actual" 24fps support it shouldn't do any pulldown since it will display at an actual 24fps, when the other device is set to output 24 fps.

the idea is that in this case neither the tv nor the player is doing any processing on the signal to make the 24fps movie into 60.

however he has a Samsung Series 3 or 4 tv if I remember correctly, I'm pretty sure this set don't support 24 fps input. howver it may have a "cinema" mode, wich does kind of the opposite of trying to match a 24 fps signal into the tv's 30/60 native signal by processing the signal with a 3:2 pulldown.

[jerzdawg]

nm, dead monkey decided to read the OP... sorry!

Edited July 8, 2009 by jerzdawg

[Dead_Monkey]

I may have read incorrectly ... but do all BD players support 24fps output?... I think there is a setting on the PS3 for 24fps ..so.. do we know if his player is capable?

He specifically said that his player has a 24fps and a 60fps mode, and that when he switches it to 24fps, he is experiencing subjectively worse video quality than when he switches it to 60fps.

Whatever the technical reason, I think we all agree on the solution: switch it to 60.

[DaDude]

If the TV has "actual" 24fps support it shouldn't do any pulldown since it will display at an actual 24fps, when the other device is set to output 24 fps.

the idea is that in this case neither the tv nor the player is doing any processing on the signal to make the 24fps movie into 60.

however he has a Samsung Series 3 or 4 tv if I remember correctly, I'm pretty sure this set don't support 24 fps input. howver it may have a "cinema" mode, wich does kind of the opposite of trying to match a 24 fps signal into the tv's 30/60 native signal by processing the signal with a 3:2 pulldown.

Yes, Series 4 is what I have. I think you hit the nail right on the head with your answer. Thanks.

[Skulltrail]

60 FPS is typically a better choice than 24 FPS mostly because more frames are thrown at you at the same time so you notice more details and enjoy the movie better. I suggest leaving your TV @60 FPS rather than trying to limit it to whatever standards the input device may have.

[majortom1981]

Fro mwhat I understand film is shot at 24fps. So when you set the player to 60 it will prob insert frames to make the movie look like 60fps and make it appear to be smoother.

[notuptome2004]

60 FPS is typically a better choice than 24 FPS mostly because more frames are thrown at you at the same time so you notice more details and enjoy the movie better. I suggest leaving your TV @60 FPS rather than trying to limit it to whatever standards the input device may have.

most movies are shot @ 24FPS now days and when you have proper support for it the movie will look fantastic more detail is shown

[Coldgunner]

By outputting 24fps video at 60fps means the player has to insert additional frames. it has to insert 6 extra frames to make it 30fps. That means one additional frame for every 4 frames.

The tv then scans twice per frame to give 60fps.

With PAL its far simpler in that its 25fps video scanned twice without inserting frames. PAL tv's operate at 50hz.

With 24fps video at 60hz you get a jittering effect on certain panning shots. with 24fps running at 24hz there is no conversion or insertion of frames, its all played at native.

[DaDude]

By outputting 24fps video at 60fps means the player has to insert additional frames. it has to insert 6 extra frames to make it 30fps. That means one additional frame for every 4 frames.

The tv then scans twice per frame to give 60fps.

I see what you're talking about. I guess 24 fps works best with TVs that are 1080p and are 120fps. So, the TV will just take the 24fps and scans it 5x per frame to give it 120fps. With a 60fps TV like mine, it needs to add the extra frames in order to scan it twice. Hence, the lower quality I'm getting with 24fps. Thanks so much for the help.

[+StevoFC MVC]

I see what you're talking about. I guess 24 fps works best with TVs that are 1080p and are 120fps. So, the TV will just take the 24fps and scans it 5x per frame to give it 120fps. With a 60fps TV like mine, it needs to add the extra frames in order to scan it twice. Hence, the lower quality I'm getting with 24fps. Thanks so much for the help.

It has nothing to do at all with what you just said. lol

[Coldgunner]

It has nothing to do at all with what you just said. lol

indeed

the 24fps video will be converted to 30fps then each frame would be displayed 4 times by the tv at 120hz.

[DaDude]

It has nothing to do at all with what you just said. lol

OK, care to explain why 24fps looks worse on my TV?

Edited July 9, 2009 by xraffle

[Coldgunner]

because there is extra frames inserted (basically duplicated frames) it causes an instantanious freeze. its not noticable normally until there is particular panning shots. Its barely noticable in fast paced action.

this should help too

http://en.wikipedia.org/wiki/Telecine#2:3_pulldown

http://www.zerocut.com/tech/pulldown.html

Video converted properly to another framerate will use combinations of the previous and next frame to create a smoother image.

For the PAL 25fps release the video is (mostly) just sped up. Which is why PAL movies often have shorter runtimes than the NTSC counterpart.

[HawkMan]

Actually the 100 and 200 hz screens don't simply show the same image multiple times to increase the refresh rate. since LCD's don't really have refresh rates. It is what old CRT's would do to create "smoother" less flickery images. The new 100 and 200 hz LCD's however will create intermediate subframes... more or less successfully...

basically the TV guess what the frame(s) between the actual film frames look like. of course this means that the smoothmotion and motion+ and motion whatever TV's the different makes put out, actually alter the output of the film and often creates artifacts in the sub frames the tv creates itself.

though in your situation the quality loss comes from the tv not having software to understand 24 fps at all and only working at 50/60 hz. so when you set the BD player to output at 24 the TV tries to mash it together into a 60 or 50 fps image since that's all it knows. despite there not being any good reason why not all LCD tv's shouldn't support 24 fps, outside of the maker having a sales argument for the higher end sets.

in any case the result is that on cheaper sets, just leave it at the sets native fps. and if possible use the cinema mode to try and smooth out the effects of the pulldown. The irony is that they create a software solution to fix a problem they could more easily fix by making the sets software support 24fps natively, and then they use the inferior software hack as a sales argument. though it's necessary for old DVD players that will output at 30,50 or 60 in any case so...

[DaDude]

because there is extra frames inserted (basically duplicated frames) it causes an instantanious freeze. its not noticable normally until there is particular panning shots. Its barely noticable in fast paced action.

Well you just said that on a 120 hz TVs, "the 24fps video will be converted to 30fps then each frame would be displayed 4 times by the tv at 120hz." Well most 1080p HDTVs are 120 hz, so why isn't there any deterioration in picture quality when converting the 24fps to 30?

[Coldgunner]

Its not picture quality that suffers, its the smoothness of the image.

[bobbba]

Well you just said that on a 120 hz TVs, "the 24fps video will be converted to 30fps then each frame would be displayed 4 times by the tv at 120hz." Well most 1080p HDTVs are 120 hz, so why isn't there any deterioration in picture quality when converting the 24fps to 30?

Most 1080P TV's are not 120Hz. Older ones are mainly 60Hz and many newer ones are either still 60. The more expensive ones can be 100, 120, 200 or 240Hz.

[DaDude]

Most 1080P TV's are not 120Hz. Older ones are mainly 60Hz and many newer ones are either still 60. The more expensive ones can be 100, 120, 200 or 240Hz.

So, what kind of TV do you need to benefit from 24fps?

[+StevoFC MVC]

So, what kind of TV do you need to benefit from 24fps?

There isn't a specific kind. Some natively support 24hz without pulldown. It varies by model...

[TruckWEB]

It's a big enough feature, so you're going to see it in the spec of the TV. If you don't see anything about 24fps, it most probably means that your TV don't support it natively.

[arrrgh]

indeed

the 24fps video will be converted to 30fps then each frame would be displayed 4 times by the tv at 120hz.

Errr what? Any decent 120hz TV does 5:5 pull down..