LG BD360 BluRay plays at 60Hz but I need 50Hz

mdo

Standard Member
Hello,

I have a LG BD360 hooked up to a LG 37LY95 TV using HDMI. I believe the TV is 50Hz, and it accepts 24Hz/50Hz/60Hz. If the TV receives 24Hz or 60Hz then I think it converts those to 50Hz. I'm in the UK. I bought the TV 2 years ago. I bought the bluray player last week and its updated to the latest firmware using internet connection.

Playing standard definition DVD is great. The player does 2:2 pulldown with 4% speedup. Motion and panning is smooth. TV displays "1080p 50Hz" so I know its receiving 50Hz from the player. I know the film and I know its playing 4% faster. This is great, life is good.

When I play BluRay the problem starts. The player outputs 60Hz! This I really don't understand. It plays at the original film speed. I assume the player is doing 3:2 pulldown. The TV displays "1080p 60Hz". So then the TV must be converting 60Hz to 50Hz. The motion and panning is not right.

The manual for the LG BD360 says it outputs 50Hz, thats what I have ticked in the options (not 24Hz which is the only other choice). There is no mention of 60Hz anywhere in the BD360 manual. Yet it outputs 60Hz !

All I'm looking to do is watch BluRay using 2:2 even pulldown with 4% speedup, so that my TV has nothing to do, and the TV gets native 50Hz input, just like when upscaling standard DVD. Why isn't it doing that?

The really frustrating part is I had the Sony BDP360 before and hit the same problem. I replaced it with the LG BD360 because the LG seemed very clear in the manual that it output 50Hz. Maybe its something to do with the TV then.

All I can think is that since the TV is 60Hz capable, the player prefers to send 60Hz. I've looked through all the options of the TV and don't seem to be able to turn off the 60Hz capability. Is there a dongle or something that I can buy that tricks the player into thinking the TV doesn't support 60Hz, so then it has to send 50Hz ? I'm clutching at straws.

Can anyone help?
Thanks in advance. Fingers crossed.
 

Ian_S

Distinguished Member
I'm afraid you are asking for the impossible.

Nearly all Blu-ray films are 24fps, which means you need a TV capable of displaying 24p, or a multiple of, to get the same smoothness as a UK 50Hz DVD. If your TV won't accept 24p, then all players will output such discs at 60Hz using 3:2 pulldown and introducing a slight judder.

Some video processors will frame rate convert 24fps to 50, however it probably won't be any smoother as they cannot speed it up, so will also have to repeat frames in odd sequences.

You need to tell the player and TV to use 24p, and then IF the TV handles that correctly, you should get smoother pictures again. If not, and some TV's take 24p input and convert to 60Hz, then the only fix is a new TV that does handle 24p correctly. IF you have a disc where you can notice the problem very easily, then taking it to a shop where you can try on different screens would be the best way to test to make sure you are happy. :smashin:
 

peterjcat

Active Member
Agreed. Also, your TV doesn't convert different sync rates to 50Hz. It will happily sync to either 50Hz or 60Hz, depending on the source, and it doesn't prefer one to the other.

Your PAL DVDs are already encoded at 25.000fps, there is no speedup done by the player or the TV, they are just displayed at 50Hz. If you put in an NTSC DVD or a Blu-ray, there is no way to display that at 50Hz.

I know there's a 24Hz/50Hz option in the BD360 and always wondered what it was doing there, as you'd never want a 24fps BD output at 50Hz (given the impossibility of speedup on-the-fly). I assume it was originally 60Hz for the US market and someone mistakenly changed it to read 50Hz for Europe. As you have discovered, it really outputs 60Hz which is the only thing it can do if 24Hz is not available -- using 3:2 pulldown as you say.

The TV won't be converting 60Hz to 50Hz, it will just be displaying 24fps at 60Hz with the attendant pulldown judder. This can be very distracting if you're used to PAL video which has no judder; people from NTSC countries are much less likely to see it (and may even prefer it, as it looks like film to them). As Ian_S says, the only way around it is to get a TV that accepts a 24fps signal at an even multiple of 24, and I think your TV is probably just slightly too early.

I have a Panasonic G10 that displays Blu-ray at 96Hz and is perfectly smooth; however I'm having a separate problem with the BD360. I believe that when set to 24Hz mode, the BD360 is outputting at 24.000Hz whereas almost all BDs are encoded at 23.976fps, resulting in 1 dropped frame in every 1000. However, this may well be a compatibility issue between the player and the TV. (I'd imagine LG would test their BD players against LG screens much more extensively.)
 

mdo

Standard Member
Thanks a lot for your replies!

Once thing to add. As I mentioned my TV does accept 24Hz. When i put the player into 24Hz mode, it works and the TV displays "1080p 24Hz". But. That is the worse setting. I can clearly see a slight pause in any panning or motion sequences (e.g. warner bros logo at the start of the film moving towards the viewer). That slight pause is every 0.5 seconds, lasting 0.02 seconds. Consistent with every frame being repeated twice (to make 48) but where the 12th and 24th frames are repeated 3 times rather than twice. I reckon its the TV doing that, because its a 50Hz TV. Notice that 1/50 is 0.02 second. This does not seem like "pulldown judder". Its more like sticky pausing every 0.5 seconds. Difficult to explain in English! It was this problem I first observed with the Sony, straight away, without knowing anything at all about BluRay. It drove me crazy. If you guys are right, then is there another explanation of this sticking problem I'm seeing with 24Hz ?

I thought TVs have a fixed refresh frequency. Its to do with the physical properties of the physical pixels in the screen which are built to light up for either 1/50th of a second *or* 1/60th of a second. A screen can't change the frequency it actually displays, I thought. If it refreshed faster there would be blurring, if it was slower then there would be flickering. So it has to convert its input to the physical refresh rate. No?

I really don't see why 2:2 pulldown with 4% speedup is impossible to do for BD disks. I don't disagree it may not be being done, but impossible? The frames are stored on the BD disk in sequence, aren't they, like a film reel? All it has to do is pick them up and spit them off to the TV, sending 25*2 a second, *as if* the images were 25fps. Its not like theres a clock on the disk, its just a sequence of frames, just like a film reel. Rotate the film wheel faster and the film plays faster, theres no magic. The only thing the player has to do then is increase the pitch of the soundtrack by 4% too, to avoid lip sync issues etc. Perhaps it is the audio that prevents speed up on the fly?

Thanks again for replies. This issue is really driving me mad. Its especially annoying as upscaled DVD is so good with no issues at all. Even the YouTube interface I have to admit is quite good.
 

Avi

Distinguished Member
I thought TVs have a fixed refresh frequency. Its to do with the physical properties of the physical pixels in the screen which are built to light up for either 1/50th of a second *or* 1/60th of a second. A screen can't change the frequency it actually displays, I thought. If it refreshed faster there would be blurring, if it was slower then there would be flickering. So it has to convert its input to the physical refresh rate. No?

Many display change their physical refresh rate according to setting/source material i.e. 48hz,50hz,60hz,72hz,96hz,120hz etc. The display tech itself can have inherent issues that may/may not be reduced by faster refresh rates. Also some display will accept a 24hz signal but still refresh as 60hz.

I really don't see why 2:2 pulldown with 4% speedup is impossible to do for BD disks. I don't disagree it may not be being done, but impossible? The frames are stored on the BD disk in sequence, aren't they, like a film reel? All it has to do is pick them up and spit them off to the TV, sending 25*2 a second, *as if* the images were 25fps. Its not like theres a clock on the disk, its just a sequence of frames, just like a film reel. Rotate the film wheel faster and the film plays faster, theres no magic. The only thing the player has to do then is increase the pitch of the soundtrack by 4% too, to avoid lip sync issues etc. Perhaps it is the audio that prevents speed up on the fly?

On PAL DVD the 4% speed up is done during the telecine process prior to disc production not in the player. I'm not aware of any consumer standalone player that does what you describe and l doubt there will ever be one to be honest. I'm sure it would be possible to build a device that can do this but I'm not sure why a typical CE manufacturer would.

There maybe some some type of HTPC solution that can reclock/pitch shift. I'm not sure if or how well these work with BD and you may find a new issues.

In all probability it's probably less hassle to change your display if it really is the cause of the issue.

EDIT

From a review on your display - http://stuff.tv/Review/LG-37LY95/

"Motion sickness
There's no doubt that when fed 1080p images from an HD-DVD or Blu-ray player, the 37LY95 delivers sumptuous pictures. Colours are beautifully natural with great contrast, impressive dark-scene definition and whites so bright even Daz would be proud. Edges are always composed, too.

Where the LG trips up, though, is tracking motion – its inability to cope with the HD source's 24 frames-per-second rate is manifested in jerky movement that just can't be ignored."

AVI
 
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mdo

Standard Member
I'm sure it would be possible to build a device that can do this but I'm not sure why a typical CE manufacturer would.

Because then I'd buy that player straight away rather than a new TV. Isn't that a good reason? I bought a "full HD ready 1080p" TV only 2 years ago. Why on earth should there be all this hassle. The TV is not actually incapable of displaying really good smooth BD signals, is it, at 50Hz. But they've decided not to make the BD disks or the players do that.
Why can't they do the telecine process for BD PAL disks too, in the same way they do for SD PAL disks?
It makes no sense to me why they seem to have gone backwards - they just want to sell more TVs ?
 

YellowSphere

Well-known Member
They haven't gone backwards at all.

Unfortunately, and this can't really be put delicately, if your television is no good at handling 24Hz, as it would appear, then you can't get smooth playback of Blu-Ray disc. End of.

There is absolutely no issue with the Blu-Ray disc specification, using 24Hz rather than 25Hz is definitely a step forwards, as it shows movies at their original speed, rather than being sped up.

You could try claiming that the television is not fit for purpose on the basis it does not (and hasn't from date of purchase) correctly reproduced Blu-Ray pictures and is therefore not of satisfactory quality, depends on how generous your retailer is feeling. In this climate, probably not very.
 

Avi

Distinguished Member
Because then I'd buy that player straight away rather than a new TV. Isn't that a good reason? I bought a "full HD ready 1080p" TV only 2 years ago. Why on earth should there be all this hassle. The TV is not actually incapable of displaying really good smooth BD signals, is it, at 50Hz. But they've decided not to make the BD disks or the players do that.
Why can't they do the telecine process for BD PAL disks too, in the same way they do for SD PAL disks?
It makes no sense to me why they seem to have gone backwards - they just want to sell more TVs ?

There are some Blu-ray Euro titles that are 1080i/50hz but the vast majority are 1080p/24. There no such thing as a "PAL" Blu-ray disc and one of the benefits of 1080p/24 is it's a global standard unlike legacy PAL or NTSC which both present issues at their native refresh rates i.e. 4% speed up at 50hz or 3:2 judder at 60hz.

It makes no sense that a display manufacturers should get 24hz playback wrong but some do hence the issue you have. Unfortunately the issue appears to be with you display not the the Blu-ray standard. Maybe the display manufacturer can suggest a solution if the display isn't fit for purpose with regard to 24hz input.

AVI
 

Nic Rhodes

Distinguished Member
[email protected] is a great step forward and one many of us planned for many years ago. Any move towards the use speed up or jerkyness just seems a complete move backwards 10 years in time. :confused:
 

Ian_S

Distinguished Member
Perhaps a SkyHD movies subscription is an idea for now if you don't want to replace the TV just yet. Sky have quite a few HD movie channels and also Anytime, and all their stuff is 50Hz as that is the European broadcast standard, so they would behave like your DVD's on your TV.

However, for Blu-ray, a TV that handles 24p properly is the way to go. Early 1080p sets didn't always do 1080p/24 or handle it properly. However, retailers and manufacturers were never quick to point such things out, if indeed many of the former even understood it.
 

mdo

Standard Member
Wow. Thanks for all the responses. Telling it how it is, is much appreciated.

Ok. I agree now that [email protected] *is* a step forward. We don't want to keep the old problems. I didn't realise BluRay is a global standard now (no more PAL/NTSC), thats good too. It seems I've been caught out on the TV then. At the end of the day, I have been using it for 2 years. I can hardly claim I bought it specifically for bluray otherwise why didn't I get bluray earlier and complain within the warranty period.

Moving on then. Two more questions if its ok. I'm now in the realm of not having hunted online first for the answers, so apologies if this is already answered zillions of times elsewhere.

1. Am I right in thinking I should avoid "100Hz" TVs then? Since this isn't a multiple of 24. Do 48Hz TVs exist? Thats all we really need isn't it? Our human eyes can't distinguish beyond that can they?

2. I was thinking of getting Virgin Media (V+ box). This has iPlayer HD and streaming movies HD on demand I believe. Will it be ok with my current TV ? Since its impossible to display even-pulldown at the original film speed on my TV, what would I see from that service ?

Thanks again!
 

YellowSphere

Well-known Member
"100Hz" is just a name applied to frame interpolation processing features for marketing purchases. Put another way, if you put something shot at 50Hz into an LCD TV with 100Hz it uses guesswork to interpolate what the camera would have shot at 100Hz by creating one intermediate frame for each pair of source frames. Obviously, because it's guessing, it can sometimes get it wrong, and different manufacturers processing fares differently in this area. In my opinion, Sony are the best, followed by Toshiba and Panasonic, then Samsung, with LG and Sharp way behind. The other problem with 100Hz is that stuff looks inherently different when shot at a higher frame rate, i.e. it will make (in the vast majority of cases) material shot an film look as if it was shot with video. A lot of people liken it to making a high budget movie look like it was shot on a cheap hand held camcorder.

At any rate, 100Hz TVs are still not fixed to 100Hz. They will most likely refresh at either 96Hz or 120Hz when fed 24Hz input.

Re: V+ HD stuff, anything on BBC iPlayer will definitely be 50Hz, as all of their own programming is shot at this speed. I would imagine that other On Demand is also at 50Hz, but don't know for sure.
 

mdo

Standard Member
A refresh rate of 48Hz, with interpolation of one frame inbetween each of the 24fps film frame, would do that. Why do we need higher refresh rates than 48Hz ?
I thought the 96Hz might do 4:4 pulldown (in which case you still see the film as it is on disk which many film buffs like and recommend) OR it might do interpolation as an option (which film buffs don't like, depending on the film). But you seem to say 96Hz *means* interpolation.
 

Avi

Distinguished Member
1. Am I right in thinking I should avoid "100Hz" TVs then? Since this isn't a multiple of 24. Do 48Hz TVs exist? Thats all we really need isn't it? Our human eyes can't distinguish beyond that can they?

2. I was thinking of getting Virgin Media (V+ box). This has iPlayer HD and streaming movies HD on demand I believe. Will it be ok with my current TV ? Since its impossible to display even-pulldown at the original film speed on my TV, what would I see from that service ?

Thanks again!


Usually the "100hz" term applies to PAL broadcast material. I think originally it was a features of the later CRT based displays to overcome the perception of flicker. I'm not sure if it means the same across different display techs that use the 100hz label. My guess is it may also be associated with the reduction of motion smear/blur on some display techs particularly with interlaced video material. 100hz shouldn't be applied to 24hz Blu-ray and the display should switch to a different refresh rate that is a multiple of 24. Some display techs work fine at 48hz whilst others may no look so good largely due to the physiology of human visual perception.

Some displays techs use a refresh rate that is multiple of the input rate. Often this is to help overcome some issue with the display tech. Providing the refresh rate is an integer multiple of the input most people won't have an issue from simple frame repeat. Obviously frame interpolation is something different and may have undesirable results.

AVI
 
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