Occasional judder and what to do about it? (1 Viewer)

[Bartman]

On several infrequent occasions I have noticed picture judder on network OTA programs and from my Roku 3 streaming box on my LG OLED TV. When this has happened I've turned on the (normally off) TruMotion setting to smooth out the picture. Judder occurred on last week's episode of The Blacklist on NBC and TruMotion couldn't fix it, so I turned TruMotion off and turned off the (normally on) RealCinema setting and voila, the judder was completely eliminated.
Can anyone explain this occasional judder? Is a BIT being inadvertently set (studio error) in the incoming video stream that is causing pulldown when none is required?
I hope this post helps others out there that may have experienced the same problem.

 

[JohnRice]

I would leave all those supposedly “improvement” modes turned off. RealCinema isn’t needed if you have a disc player that can output a 24P signal with film sourced material. Those things are just marketing items that tend to create more problems than they cause. RC must have been triggered by something when it shouldn’t have been.

 

[Bartman]

I would leave all those supposedly “improvement” modes turned off. RealCinema isn’t needed if you have a disc player that can output a 24P signal with film sourced material. Those things are just marketing items that tend to create more problems than they cause. RC must have been triggered by something when it shouldn’t have been.

This is where it gets a little confusing. LG's RealCinema does 24Hz (fps) to 120Hz (TV refresh rate) 5x conversion. I believe RealCinema should be OFF for regular 480/60Hz or 1080/60Hz sources, such as ATSC & DVD, but ON for 24fps sources such as my Blu-ray player and Roku. I assume the TV automatically detects 60Hz sources and converts them to 120Hz.
The reason for performing 24 to 120 conversion in the TV is the HDMI2.0 bandwidth limitation of 2160/60.

 

[JohnRice]

OK, common misperception. Your TV never receives a 120Hz signal. As you already stated, your TV can't receive a 120Hz signal. The reason for a 120Hz refresh rate is that 120Hz is the lowest frequency that can be fully divided by 24, 30 and 60 Hz. Let's just not go into the detail that 30Hz is actually 29.97Hz.

There is actually zero need for any of these processing modes, if your sources are configured correctly. Your player and hopefully your streaming box should have a 24P mode for film sourced material. You want to activate that. Then the TV is sent everything in its native frame rate, rather than 24P material having extra frames added to get it to 30Hz.

So, when your TV receives a 24Hz signal, it automatically knows to scan each frame 5 times. When it's 30Hz, it knows to scan it 4 times and when it's 60Hz it knows to scan it twice. No additional processing needed. That RealCinema mode appears to be intended to fix a 24Hz signal that's had extra frames added (Pulldown) to get it to 30 Hz. Clearly it's flawed, and as long as your sources are properly configured, it's not needed.

As a general rule, all of those whizbang, high tech, miracle processing modes cause more problems than they solve. Calibrate your colors and dynamic range, configure your sources correctly, and leave all those other "fixes" turned off.

 

[Harry-N]

I remember noticing some OTA network "judder" way back in the early 2000s when we were still watching on CRTs. I believed then, as I believe now, that it was intentional, and done as a means to speed up the program to allow more time for ads and promos.

 

[Johnny Angell]

There is actually zero need for any of these processing modes, if your sources are configured correctly. Your player and hopefully your streaming box should have a 24P mode for film sourced material. You want to activate that. Then the TV is sent everything in its native frame rate, rather than 24P material having extra frames added to get it to 30Hz.

Does the 24P mode have to be manually turned on and off depending on what’s being watched?

 

[JohnRice]

Does the 24P mode have to be manually turned on and off depending on what’s being watched?

No. It just enables 24P output as opposed to using pull down to increase 24P material to 30Hz. If the TV is compatible, you activate it and leave it on. If not, as in a TV with only 60Hz refresh rate, you leave it off.

To clarify. Last year I got a new TV in the living room that has a 120Hz refresh rate. The previous one was 60Hz. So, 24P was turned off in my sources. With the new TV, I activated it in the disc player and AppleTV and that was that.

 

[TheFOMO]

OK, common misperception. Your TV never receives a 120Hz signal. As you already stated, your TV can't receive a 120Hz signal. The reason for a 120Hz refresh rate is that 120Hz is the lowest frequency that can be fully divided by 24, 30 and 60 Hz. Let's just not go into the detail that 30Hz is actually 29.97Hz.

There is actually zero need for any of these processing modes, if your sources are configured correctly. Your player and hopefully your streaming box should have a 24P mode for film sourced material. You want to activate that. Then the TV is sent everything in its native frame rate, rather than 24P material having extra frames added to get it to 30Hz.

So, when your TV receives a 24Hz signal, it automatically knows to scan each frame 5 times. When it's 30Hz, it knows to scan it 4 times and when it's 60Hz it knows to scan it twice. No additional processing needed. That RealCinema mode appears to be intended to fix a 24Hz signal that's had extra frames added (Pulldown) to get it to 30 Hz. Clearly it's flawed, and as long as your sources are properly configured, it's not needed.

As a general rule, all of those whizbang, high tech, miracle processing modes cause more problems than they solve. Calibrate your colors and dynamic range, configure your sources correctly, and leave all those other "fixes" turned off.

The problem is that stutter is still noticeable due to the sample-and-hold plus super fast processing of OLED unrelated to the incoming signal. There will always be a slow pan that pushes the OLED beyond its ability to cope.

 

[JohnRice]

The problem is that stutter is still noticeable due to the sample-and-hold plus super fast processing of OLED unrelated to the incoming signal. There will always be a slow pan that pushes the OLED beyond its ability to cope.

You would know more about that than I do. I just find that often people use processing that causes problems rather than eliminate them.

 

[TheFOMO]

You would know more about that than I do. I just find that often people use processing that causes problems rather than eliminate them.

Agreed - my point is that TV processing is not designed to fix this, so i'm in agreement with you - processing is at best hit or miss

 

[Bartman]

Thanks everyone. Let me see if I've got this right. Turn RealCinema OFF for all sources and let the TV decide what conversion is necessary?
My Roku 3 does not have a 24Hz setting, it outputs everything at 60Hz. Newer Roku 4K players have an Auto-Adjust Display Refresh Rate advanced setting, that I assume allows for 24Hz output. My question is: does 60Hz cause picture quality degradation in comparison with 120Hz because 60 is not an integer multiple of 24 but 120 is?
My Sony BDP-S6700 Blu-ray player does have a 24Hz setting, it is presently set to the recommended default of AUTO. I have no reason to suspect, from what I've observed, that there is anything wrong with this setting.

 

[TheFOMO]

Thanks everyone. Let me see if I've got this right. Turn RealCinema OFF for all sources and let the TV decide what conversion is necessary?
My Roku 3 does not have a 24Hz setting, it outputs everything at 60Hz. Newer Roku 4K players have an Auto-Adjust Display Refresh Rate advanced setting, that I assume allows for 24Hz output. My question is: does 60Hz cause picture quality degradation in comparison with 120Hz because 60 is not an integer multiple of 24 but 120 is?
My Sony BDP-S6700 Blu-ray player does have a 24Hz setting, it is presently set to the recommended default of AUTO. I have no reason to suspect, from what I've observed, that there is anything wrong with this setting.

If Roku is converting 24p to 60, then it's already incorporated the judder into its 60hz signal because 24 is not evenly divisible into 60 - so if you receive this signal from the Roku3 it will be garbage in garbage out.

It's best to receive everything as a native 24 and let your TV's latest processor decided what to do.

With your Sony player I'd output everything as native to the source (could be 24 could be 60 if it's Gemini Man) and again, let the TV make the necessary adjustments of the native material.

The latest TVs from LG, Sony and Samsung have way better motion processors than any streaming product because the processing is unique to their TV panel. But as always, try it both ways - if stutter appears while in native mode, switch over to the 60hz or whatever processing offered by the source device. Motion processing is currently the black hole of confusion that cannot be easily fixed without a few things falling into place.

 

[Harry-N]

When we first got a Blu-ray player (Sony BDP-570) years ago, we were in the midst of watching STAR TREK: DEEP SPACE NINE on DVD. After seeing how nice most Blu-rays and DVDs looked on our 60" Sony TV, I was horrified to see this juddery effect on DS9. I tried all kinds of settings on the TV and the player with no success for a few days. Finally, I stumbled on a thread, either here or another forum, that suggested that on the Blu-ray player's settings, that I should go to the:

24p Output section
The two choices there are "Auto" or "Off" and for me to set it "Off."

That did it for DEEP SPACE NINE. The motion was smooth thereafter. One thing I'd noticed was that the judders occurred whenever the episode starting credits were being superimposed, or when a special effect was on-screen.

This sort of made sense to me as DS9 had been filmed in 24p, but its special effects were done in the video realm, which is 60p, right?

Anyway, while watching DS9, I left the setting at "Off", and when finished, I set it back to "Auto".

 

[TheFOMO]

...This sort of made sense to me as DS9 had been filmed in 24p, but its special effects were done in the video realm, which is 60p, right?

Anyway, while watching DS9, I left the setting at "Off", and when finished, I set it back to "Auto".

Don't get me started. That's why there's the 2K intermediate to make sure everybody is on the same resolution, etc.

 

[Bartman]

If Roku is converting 24p to 60, then it's already incorporated the judder into its 60hz signal because 24 is not evenly divisible into 60 - so if you receive this signal from the Roku3 it will be garbage in garbage out.

It's best to receive everything as a native 24 and let your TV's latest processor decided what to do.

With your Sony player I'd output everything as native to the source (could be 24 could be 60 if it's Gemini Man) and again, let the TV make the necessary adjustments of the native material.

The latest TVs from LG, Sony and Samsung have way better motion processors than any streaming product because the processing is unique to their TV panel. But as always, try it both ways - if stutter appears while in native mode, switch over to the 60hz or whatever processing offered by the source device. Motion processing is currently the black hole of confusion that cannot be easily fixed without a few things falling into place.

Apparently the reason Roku outputs 60Hz is, some older TVs did not support 24Hz but all TVs support 60Hz.

The intent of this post was to alert LG TV owners that RealCinema is motion processing (that I wasn't aware of) just like TruMotion and the default should be OFF.

 

[Josh Steinberg]

This sort of made sense to me as DS9 had been filmed in 24p, but its special effects were done in the video realm, which is 60p, right?

Kinda, sorta.

DS9 followed what was an industry standard workflow at that time. The programs were shot on film at 24fps. The unedited film was put through a telecine transfer process that resulted in a 29.97 NTSC video conversion. Then the material was edited on tape at 29.97, and effects were done at 29.97 too.

The issue with playback of those titles is that you can’t really go back to 24fps because all of the post-production work was done at 29.97. Those video masters are only ever going to look right at 29.97.

At the time, no one imagined that TVs would one day handle 24fps or that viewers would ever be watching content at a higher quality than standard definition. Shooting on film allowed studios to retain the high quality look of film productions (and film cameras in that era were also more reliable and easier to use than video cameras), but editing on tape allowed the whole process to be timely and affordable on television budgets and timeframes.

 

[Bartman]

I have follow up questions, highly related to this discussion:
1. Would I see a picture quality difference between my Roku 3 and a Roku Ultra (that is capable of outputting 24fps) when streaming movies from Netflix or Prime? Note: in the past when I've compared Blu-ray to streaming, Blu-ray was better.
2. Does the streaming app built into my LG B8 OLED TV also have 24fps capability? Note: I've never used this app.
3. Does the LG app have 24fps 4K capability?

 

[TheFOMO]

Kinda, sorta.

DS9 followed what was an industry standard workflow at that time. The programs were shot on film at 24fps. The unedited film was put through a telecine transfer process that resulted in a 29.97 NTSC video conversion. Then the material was edited on tape at 29.97, and effects were done at 29.97 too.

The issue with playback of those titles is that you can’t really go back to 24fps because all of the post-production work was done at 29.97. Those video masters are only ever going to look right at 29.97.

At the time, no one imagined that TVs would one day handle 24fps or that viewers would ever be watching content at a higher quality than standard definition. Shooting on film allowed studios to retain the high quality look of film productions (and film cameras in that era were also more reliable and easier to use than video cameras), but editing on tape allowed the whole process to be timely and affordable on television budgets and timeframes.

So are the digital intermediate transfers today all done in 24 or 30p? Given that TVs capable of 120Hz are falling below $1,000, they no longer have to take into account TV limitations and can focus on source image quality.

 

[Worth]

So are the digital intermediate transfers today all done in 24 or 30p? Given that TVs capable of 120Hz are falling below $1,000, they no longer have to take into account TV limitations and can focus on source image quality.

Feature films have always been 24fps, as was television shot and edited on film - so pretty much everything prior to the mid-80s. From the mid-80s to the late-90s, video post production became the standard in television, so everything switched to 30fps. Once television post production transitioned to HD in the late-90s/early-00s, it shifted back from 30 to 24.

 

[jcroy]

Feature films have always been 24fps, as was television shot and edited on film - so pretty much everything prior to the mid-80s.

How common were films done as 25 fps ?