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[jmone]

MC12 can be configured to change resolutions when playing Video files.  It would be great if you could select DIFFERENT video settings pending the type of video content being played.  While I can make a script to do this manually (will post an example here later), I'd love to be able to specify in MC for it to change the outputs between
1) 1920x1080/50hz (for DVT-B, PAL DVD's, and 25p / 50i files),
2) 1920x1080/60 (for NTSC Disks and 30p / 60i files), and finally
3) 1920x1080/24hz (for Blu-ray, HD-DVD and 24p files).  This could be done by reading the existing Meta Data or by having a new field such as "Output Resolution".

Thanks
Nathan

[Matt]

Not really an answer, but a related FYI because I don't think many people know it exists:

Media Center launcher can be used to switch monitor layout, configuration, etc. which is useful for theater configurations. (run MC12.exe /MonitorSwitch for instructions)

[jmone]

It's interesting that I have never experienced any refresh rate problems.

I don't have a digital video projector or big screen LCD or plasma television units yet, but our CRT televisions (through S-video) and LCD PC displays (through analog VGA, DVI or internal on laptops) can show all video types perfectly fine at the default 60 Hz refresh rate.

The type of the video file doesn't matter at all - 23.97, 24, 25 or 29.97 fps, interlaced or progressive - everything seems to work without problems, but maybe I am missing something that should be obvious.

I have only the CCCP codec pack and standard display drivers installed. All related settings are at the default values.

I have very few HD resolution files, but I suppose the pixel resolution is not a related factor.

The obvious sign of frequence mismatch is apparant on content with steady movement, you will see a slight but regular pause/jerk/jitter when the duplicate frames are inserted breaking the smooth flow of the movement (eg most noticable on a ticker tape running at the bottom, people/cars moving steadly across the screen, sports when you a following a ball etc) .

While you will have the issue on your screen you may not have noticed it (but it really distracts me!) but the issue will be less visible on smaller format screens (actually the ratio of screen size to seating distance).  While physical resolution plays little part, the "perceived resolution" does - the further you sit away from a screen (or the smaller it is or both) the less issues you will see).  There is a discusion here on perceived resolution ( http://www.carltonbale.com/2006/11/1080p-does-matter/ ).  On a 60" screen at a 2m veiwing distance it is unfortunatly very noticable for me (and was just as annoying on my 42"). 


Thanks
Nathan

[jmone]

Not really an answer, but a related FYI because I don't think many people know it exists:

Media Center launcher can be used to switch monitor layout, configuration, etc. which is useful for theater configurations. (run MC12.exe /MonitorSwitch for instructions)

Likewise under "Display Settings" you can select a Resolution/Bit Debth for playback but not a Refresh Rate.  I think that issue of mismatched timings from HTPC will become more apparant as:
1) HTPC's are becoming more common for playback of multiple source media types
1) Bigger format TV's are now common
2) Different frequency format media is becoming common (eg 24p Blu-ray & HD-DVD Disks, PAL / NTSC media from the net or imported on disk from other countries)

Thanks
Nathan

[glynor]

The obvious sign of frequence mismatch is apparant on content with steady movement, you will see a slight but regular pause/jerk/jitter when the duplicate frames are inserted breaking the smooth flow of the movement

One tiny little nerd-niggle...  Duplicate "frames" are effectively never inserted with any commonly-used pulldown pattern (excepting some really wonky ones used on freakish ultra-low framerate anime stuff).  Duplicate "fields" are inserted in most pulldown patterns.  A "field" is not equivalent to a "frame".

There really is no such thing as a "frame" in interlaced video.  There are only fields equally spaced in time.  In relation to interlaced video, the term "frame" is an artificial construct that makes it easier for us mere-mortals to relate interlaced video to film sources.  The video stream and receiving device (the TV) don't know or care which field belongs to which frame.  It only sees a string of fields each 1/60th of a second apart (or 1/50th of a second for PAL).  Field 1 is equally distant from Field 2, which is equally distant from Field 3.  Fields 3 & 4 have no special relationship, except that they are next to one another (same as Fields 2 & 3).

The difference is that when an extra field is inserted, it gets displayed on screen simultaneously with a portion of the following frame (because a field is made up of alternating even or odd numbered resolution lines)...  So the "frame" is half the preceeding frame and half the following frame.  Again though, it isn't a full frame (1/30th or 1/25th of a second) that gets inserted, it is one field (1/60th or 1/50th of a second), and it never displays on screen "alone".

Also... I'm a bit confused by why this is an issue still.  On a progressive scan device (such as a computer monitor, LCD/Plasma TV, or a Projector) none of this should matter at all as long as the decoding device used (the DVD player or software program) are properly deinterlacing the feed.  If you are using a progressive scan device, and you are suffering from artifacts related to pulldown, then your decoding filters are not doing reverse telecine properly (often called "3:2 pulldown detection" for us NTSC folks).  If you are using a DVD Player and you are seeing artifacts, then you need to purchase a DVD player that properly supports the pulldown removal for the region you live in (most "progressive scan DVD Players" support both NTSC and PAL pulldown removal anymore).

This issue should be limited to (a) people using interlaced displays (CRT TVs and 1080i-only HDTVs), and (b) people using really weird content.

Jmone... What decoding filters are you using to view this 24fps content, and are you sure you have deinterlacing properly enabled?  Or are you keeping a TV that is only 720p set to 1080i?  If so, then that is your problem.  Except for interlaced content (sports mostly) you don't ever want to "force" your TV into 1080i mode!  Most TVs detect the incoming signal.  If you are using a 720p/1080i TV, you'll want to set your desktop resolution (and display resolution) to 720p (1280x720), not to 1080 (1920x1080), or your TV will display interlaced content and you'll have artifacts.  If set your TV to 1080i "resolution" and then drop the refresh rate to 24hz, that's the same net effect as 720p because the lower frame rate halves the "apparent" resolution on screen.  Not to mention that a "720p/1080i TV" can't "really" display 1080 lines of resolution.  The native resolution is what the native resolution is.  When you set it to 1080i, it only draws 540 lines on the screen at any one moment (it just does it twice as fast so the "resolution" is 540*2 = 1080).

[glynor]

Hmmmm.... I'm wondering if we are talking about two separate things.  What resolutions and refresh rates does your TV support?  Is it a CRT or a LCD/Plasma display?  All this stuff should apply to CRTs, but not really apply to LCDs/Plasma TVs (which are ALWAYS progressive and don't really have a refresh rate at all).  If you do have a progressive-native device, perhaps what you are experiencing is actually Flicker: http://en.wikipedia.org/wiki/Flicker_fusion_threshold

However, I suspect you are using a CRT or other interlaced-native device, because you've repeatedly referred to refresh rate.  Windows XP won't even show you a refresh rate setting for a LCD/Plasma device that is properly connected, because there is no such thing...

As far as HDTV, the standards are:

720p60 (NTSC) and 720p50 (PAL)
1080i60 (NTSC) and 1080i50 (PAL)
1080p30 (NTSC) and 1080p25 (PAL)

There is no 1080p60/50 in the standard broadcast specification on any continent.  It is destined to be used "for future content" but for now, any 1080 signal will be either progressive and 30/25 fps or interlaced and 60/50 fields per second, it will NEVER be progressive and 60/50 fields per second.  Some cameras can record at those speeds, but not many.

So.... I'm wondering what you have your monitor set to normally, and what your resolution settings are on the desktop.  Your computer can't "insert" pulldown on the fly (it must be encoded in the source video), and I don't think it should be an issue for HD-DVD and BluRay content, which should just be progressive.

[jmone]

Ahhh and this is the nub of the issue - its not what the TV receives it is what the HTPC sends and the conversion it has had to do!

My TV is a Kuro Plasma 60" that support the following Video signals over HDMI (there are additional PC ones) and will sync to what ever it recieves automatically from the list below:
720(1440) x 480i@59.94/60hz
720x480p@59.94/60hz
720(1440) x 576i@50hz
720x576p@50hz
1280x720p@50/59.94/60Hz
1920x1080i@50/59.94/60hz
1920x1080p@24/50/60hz

After reading the Modelin/DTD's transmitted from the Kuro over HDMI, the reported supported output frequences from the HTPC's G33 graphics card for 1920x1080 are 23, 24, 25, 30, 50 or 60 hz.  OK - I can now have the HTPC and the Kuro play on any of these freq but given the progressive (not interlaced) nature of the HTPC and res of the Kuro the ones of most interst are 1920x1080p@24,50 or 60hz.  The HTPC's task is then to CONVERT what ever format the media is in eg (480i, 576i, 1080i, 1080p/24 etc) to the output resolution that has been set on the graphics card (eg 1920x1080p/24hz, 1920x1080p/50hz etc).  The impact is if the resolution and/or frequency is different between the media's encoding and the output selected on the HTPC it must scale (to match the resolution) and/or insert(delete) frames (to match the frequences) to the output hence introducing negative visual effects.  The solution is to change the HTPC's output to be the same as that of the media being played as both the HTPC and TV support these common formats.

Thanks
Nathan

[glynor]

That's really odd... I'll have to read up more on Plasma (which I don't fully understand).  LCDs do NOT have refresh rates at all.  They have response times, and flicker frequencies (how fast the fluorescent tube back light cycles -- usually 200hz or higher), but no refresh rates at all (the LCD "shutter" is either open or closed, never half-decayed like a CRT screen).  It seems to me from that list though that the Kuro TV is missing a whole bunch of common frame rates.

What most CRT HDTVs do to get around the problem is have "flicker free" refresh rates.  Bear in mind, to prevent flicker the refresh rate of the display does NOT need to match the frame rate of the source material.  It only needs to be high enough to provide the illusion that no mismatch exists.  For example, if you set that display to 1920x1080@120Hz, you'd never notice any issues at all.  That's how most CRT HDTVs I've seen operate...

That's because the 120Hz evenly divides by 24, 30, and 60.  The only common frame rates that don't work evenly are 25 and 50 (stupid PAL).  However, at that high of a refresh rate, it would be exceedingly rare for you to see any issue even with the worst case (1080i50 source material) because the field rate of 50hz is far too fast for the brain to process the missing fields (in other words, your brain would fill in the missing field here or there the same way that a flip-book animation works).

From what I've read in the reviews of the Kuro TVs, there is a setting in the picture adjust menu (called "Pro Adjust" in US models at least) called ADV which converts film based program material to 72fps.  There is also a "Smooth" setting which does something proprietary in the display that no one could figure out, but which was reported to work quite well.  Does yours not have the 72hz mode?  If so, I'd set it to that and forget it, and set the computer refresh rate to 72 and leave it be.  That should be high enough that you won't see any flicker at all, with any sources.

But.... Like I said... I don't fully understand how Plasmas work.  I assume you've read through some of the Kuro threads over at AVS Forum?

[jmone]

I understand the point about the response times etc for LCD though on Plasma's we have a similar decay rates for each sub pixel as you do with a CRT as they become excited and emit light with the application of a current (I think......)  but my observations are about the changes that are made at the HTPC end.  Here is my example:
1) Play HD DVB-T Broadcast in Australia - The format is 1920x1080i/50hz.  If I've set my HTPC to 1920x1080p/50hz all it has to do is to do is generate the "missing" feilds (to go from 50i to 50p)
2) Play PAL DVD - The format is 720x576i@50hz.  Again if I've set my HTPC to 1920x1080p/50hz it has to both generate the missing fields AND scale the image to 1920x1080

Both those examples look fine, the problem is with the timing mismatch of:
3) Play Blu-Ray - The format is 1920x1080p@24hz.  No scaling is required but it has to take the source material and convert it to 50hz.  In this case you can double the number of frames (to 48) nice and easilly but you still have to add 2 for for every 50 giving you that slight visible "pause" OR speed the playback up by 4% (which I don't think any PC can do).

As there is NO single (available) output setting that is divisable by 24,25 and 30 your best solution is to just change the output you transmit to suit the media's encoding - this is what the PS/3 does.

Thanks
Nathan
 
Note: The TV itself is great and there are all sorts of modes and it has fixed my Jitter problem I had with the previous Hitachi Plasma.  It supports not only the "Video" resolutions and timings I quoted but also a bunch of PC based ones that I did not as they were not relevant to this discussion.

[glynor]

Note: The TV itself is great and there are all sorts of modes and it has fixed my Jitter problem I had with the previous Hitachi Plasma.  It supports not only the "Video" resolutions and timings I quoted but also a bunch of PC based ones that I did not as they were not relevant to this discussion.

Oh, I know.  The Kuros are probably the best consumer (mass produced) plasmas there are out there right now.  To get much better, you need to move to a Pro LCD Studio Monitor (which are an order of magnitude more expensive).

[jmone]

From what I've read in the reviews of the Kuro TVs, there is a setting in the picture adjust menu (called "Pro Adjust" in US models at least) called ADV which converts film based program material to 72fps.  There is also a "Smooth" setting which does something proprietary in the display that no one could figure out, but which was reported to work quite well.  Does yours not have the 72hz mode?  If so, I'd set it to that and forget it, and set the computer refresh rate to 72 and leave it be.  That should be high enough that you won't see any flicker at all, with any sources.

Sort of but we are mixing different things as we are really talking about available video standards that used to all be aligned in one Geographic area but now we are global we have to be able to mix and match -
1) Media:  Simplistically we see main stream video encoded at 24fps (Blu-ray HD-DVD), 25p/50i (PAL), 30p/60i (NTSC) but there are many others
2) Video Signal Transition - Consumer equipment (CE) such as TV's, DVD Players etc traditionally will transmit and accept a 50 and/or 60hz signals that were related to our respective PAL and NTSC countries.  Newer CE devices (like the latest Plasmas / LCD / Bluray & HD DVD Players) will now also transmit / accept a 24hz signal as well - that’s it....there are no 72hz / 120hz / 1,000hz options available (we would need multiple HDMI/DVI in out ports to handle the bandwidth like you do with high resolution / frequency PC's and Monitors!).  The good news is we can use the 50 or 60hz to now transmit and receive a single field (eg interlaced TV) or a full frame such as the output from a PC.
3) TV's internal processing - There have been lots of claims from TV Makers (and there still) are about the internal scan/refresh rates used to energise the screen, we used to have CRT TV's claiming 100hz (probably 120hz in the US) and now we have 72hz in the new flat screens.  I can set the Kuro to 72hz and it will process whatever the signal it receives into 72 frames per second (hz).  I'm with you on this one, if the TV cannot change its internal frequency to match that of the signal it is receiving the next best thing is for a fast internal frequency as it will help minimise any visible additional mismatch frequency artefacts introduced by converting the incoming signal into the displays output scan rate.

The problem is not with the internal frequency or processing by the TV (though some TV’s like my old Hitachi had terrible processing) it is you only have MAX 3 different options for video transmission between your player and TV: 24, 50 or 60hz - Pick One....or hopefully swap between all three as you need!

In the "old days" it would be all 50hz or all 60hz.  PAL countries have always had a bit of a judder problem from mismatched timings with imported 60hz material but that was life.  Now for the first time you going to have real non interlaced 24p source material where the smarter Blu-ray / HD-DVD players (like the PS/3) will be able to read the disk and push out a 24, 50 or 60hz signal as appropriate for judder free playback OR you can choose to stick to either 24, 50, or 60 and suffer judder when there is a mismatch as the transmission device will have to convert the material by adding or removing frames to pad out the difference in the frequencies.

Anyway – I think that’ right! 

So can we please have MC12 either automagically swap between 24 /50 / 60hz by reading the media/disk directly and/or a meta data field?  You’re going to want it as you start playing you HD Disks from your HTPC to you TV….

Thanks
Nathan

[glynor]

Newer CE devices (like the latest Plasmas / LCD / Bluray & HD DVD Players) will now also transmit / accept a 24hz signal as well - that’s it....there are no 72hz / 120hz / 1,000hz options available (we would need multiple HDMI/DVI in out ports to handle the bandwidth like you do with high resolution / frequency PC's and Monitors!).

No.  That's not right.  Computers work differently from CE devices.  It may be that that particular monitor is simply not designed to be a good "computer monitor", or perhaps it does not provide appropriate connections for them because it makes assumptions about the type of device that will be connecting to it (standalone set-top devices that always transmit refresh rates matched to their frame rate).  However, the DVI specification can certainly transmit 1920x1080 at MUCH higher frequency than 24 frames (or 60 or 100 frames) per second.  True, going above 1915x1436 (2.75 megapixels) at 60hz requires a dual-link DVI connection (a single link DVI connection is 165MHz max, which translates to 3.7Gbits/s).  Dual-link does not mean dual connectors though!  Most DVI connections on graphic cards are now Dual-link (or else they cant support higher than WUXGA).  A single DVI link consists of four twisted pairs of wire to transmit 24bits per pixel.  The DVI connector and cable has a provision for a second link, which is supported by the vast majority of high-resolution monitors (and as I mentioned, graphics cards).  Any quality DVI cable should (and all do that I've ever encountered) support dual-link connections.  Its always been part of the spec.  When more bandwidth is required than is possible with a single link, the second link automatically joins in allowing up to 4 megapixels at 60Hz (or allowing much higher frequencies at lower resolutions).

Older HDMI 1.0 devices may be limited to a maximum of 165Mhz (1080p60 or 1920x1200 max), but HDMI 1.3 provides 340MHz which provides much more flexibility.

Now, your monitor might not support those connections.  Or the G33 graphics on the Shuttle system might not (most tier 1 motherboard makers didn't even support DVI or HDMI at all on their G33 boards because an additional chip was required), but it is not the fault of the connector standard.

[jmone]

Now, your monitor might not support those connections.  Or the G33 graphics on the Shuttle system might not (most tier 1 motherboard makers didn't even support DVI or HDMI at all on their G33 boards because an additional chip was required), but it is not the fault of the connector standard.

I still don't understand your point, as my TV (like most) can only accept the following Video signals - there is no other choice only 24 / 50 or 60hz:
720(1440) x 480i@59.94/60hz
720x480p@59.94/60hz
720(1440) x 576i@50hz
720x576p@50hz
1280x720p@50/59.94/60Hz
1920x1080i@50/59.94/60hz
1920x1080p@24/50/60hz

[glynor]

EDIT:  To answer your question... I was not disputing your whole comment, only that one little part that DVI couldn't handle it "without multiple DVI or HDMI in/out ports".  It clearly can, via a dual-link connection which still only requires one port and is part of the spec.

My other point is this... Assuming your graphics card can push it, and your monitor can receive and process it, you are likely going to have very good results for computer-use (including playing back footage at 24p, 25p, 30p, 60i, 60p, and everything else) by pushing the refresh rate as high as possible.  True, you will get best results by using an exact multiple (which is why 100 or 120Hz would be best if possible), but I suspect your problem might be mitigated by forcing the refresh rate to 72Hz if you can (which is at least an exact multiple of 24 and is higher than everything else).

Now, your monitor, not being a "monitor" might not support those rates (and appears not to, but I thought I read that it could do 72Hz somehow), but many monitors can and DVI certainly can.

Of course, this is not to say that your system isn't technically "better".  However, I don't know that it is necessary for the vast majority of people (and therefore would probably not be worth the development effort to switch refresh rates on the fly like that).

The reason is, I think (and I am by no means sure) that you are confusing (and I was at first) telecine (can cause judder) with refresh mismatch (can cause flicker).  I am fairly certain that the computer (or the TV) do not ever insert extra fields (or frames) into content (telecine).  Telecine is a method used during the authoring or recording of media (making the DVD, HD-DVD, BluRay encoding, or recording the footage with a camera onto an interlaced medium or format).  They do detect and remove these extra fields (reverse telecine) but they don't ever add them "on the fly".

Flicker can be caused when the refresh rate of a monitor doesn't match the framerate of the video being displayed on it.  It is caused by delayed frames. This happens when the transmitting device (the software application in this case, not the display drivers) sends a frame and the monitor/GPU/driver is half-way through the previous "scan".  Therefore it can't draw the new frame until the current one is finished.  It queues that frame until it is done, and then draws it, unless it has received a second frame in the interim (then it drops the "middle" frame, causing flicker).  However, flicker is by far most apparent when the framerate is close to the refresh rate of the monitor (which is why most video games include an option to limit the frame rate to a maximum of the refresh rate).  However, as refresh rates increase, your ability as a human to detect the imperfections in the video signal diminishes dramatically.  The reason is simple... At 100Hz, even when playing 60p content (which is exceedingly rare) relatively few frames actually get "dropped".  Some might get delayed by less than 1/100th of a second, but that's all.  Those that do get dropped are only "missing" for 1/100th of a second, and are exceptionally rare.  24p material should effectively NEVER drop a frame at 100hz, only possibly occasionally slightly delay one (and you won't ever be able to tell), which is why they call them "flicker free".

That's why "response time" on an LCD monitor is very important, for the exact same reasons.  Below roughly 5-8ms response time (real black-white response rates, not the cheesy gray-to-gray ones the cheap monitor manufacturers sometimes list), the human eye (and brain) loses all ability to distinguish flicker or lag.  That's also why the "guides" recommend that you disable those framerate limiting options in video games if you run your monitor at higher refresh rates than 60hz (or have a fast LCD monitor).  Because there might be a few artifacts there, but you'll never be able to see them and the higher framerate is better on your eyes!

What I wonder is if the distortion you are seeing would lessen, or go away, if you can force it to receive at 72Hz (again, I don't know exactly what model you have, but I've read those Panny's can do it).  If it is caused not really because of the mismatch between 24fps and 50hz, but because 50hz isn't high enough to hide the distortion from your eyes (which are probably pretty good)!

[jmone]

My other point is this... Assuming your graphics card can push it, and your monitor can receive and process it, you are likely going to have very good results for computer-use (including playing back footage at 24p, 25p, 30p, 60i, 60p, and everything else) by pushing the refresh rate as high as possible.  True, you will get best results by using an exact multiple (which is why 100 or 120Hz would be best if possible), but I suspect your problem might be mitigated by forcing the refresh rate to 72Hz if you can (which is at least an exact multiple of 24 and is higher than everything else).

Agree

Now, your monitor, not being a "monitor" might not support those rates (and appears not to, but I thought I read that it could do 72Hz somehow), but many monitors can and DVI certainly can.

It's a TV and while I could not claim that thier aren't consumer TV's that will take other refresh rates I've never heard of any...

Of course, this is not to say that your system isn't technically "better".  However, I don't know that it is necessary for the vast majority of people (and therefore would probably not be worth the development effort to switch refresh rates on the fly like that).

Mmmm depends on your use of MC - I've got one copy on a standard PC/Monitor and like traditional users I could not care less.  HTPC (as in Home Theater) users are trying to replace dedicated CE devices (TV Tuner, PVR, DVD Player, Blu-ray/HD DVD Player, Media Player) with a single HTPC outputing to a big screen and in this use judder is certainly an issue.

The reason is, I think (and I am by no means sure) that you are confusing (and I was at first) telecine (can cause judder) with refresh mismatch (can cause flicker).  I am fairly certain that the computer (or the TV) do not ever insert extra fields (or frames) into content (telecine).  Telecine is a method used during the authoring or recording of media (making the DVD, HD-DVD, BluRay encoding, or recording the footage with a camera onto an interlaced medium or format).  They do detect and remove these extra fields (reverse telecine) but they don't ever add them "on the fly".

Flicker can be caused when the refresh rate of a monitor doesn't match the framerate of the video being displayed on it.  It is caused by delayed frames. This happens when the transmitting device sends a frame and the monitor is half-way through the previous "scan".  Therefore it can't draw the new frame until the current one is finished.  It queues that frame until it is done, and then draws it, unless it has received a second frame in the interim (then it drops the "middle" frame, causing flicker).  However, flicker is by far most apparent when the framerate is close to the refresh rate of the monitor (which is why most video games include an option to limit the frame rate to a maximum of the refresh rate).  However, as refresh rates increase, your ability as a human to detect the imperfections in the video signal diminishes dramatically.  The reason is simple... At 100Hz, even when playing 60p content (which is exceedingly rare) relatively few frames actually get "dropped".  Some might get delayed by less than 1/100th of a second, but that's all.  Those that do get dropped are only "missing" for 1/100th of a second, and are exceptionally rare.  24p material should effectively NEVER drop a frame at 100hz, only possibly occasionally slightly delay one (and you won't ever be able to tell), which is why they call them "flicker free".

 

I'll stand to be corrected if there is another term other than judder (I don't think it is jitter) from what I'm seeing... be it intoduced by the telecline process of what ever the process is used on the HTPC when it manipulate say 24 frames into a 50 or 60hz stream.  What I see is not a constant jitter but a slight pause each second that seems to relate to the last frame being held for the extra 2 cycles in 50hz

  That's why "response time" on an LCD monitor is very important, for the exact same reasons.  Below roughly 5-8ms response time (real black-white response rates, not the cheesy gray-to-gray ones the cheap monitor manufacturers sometimes list), the human eye (and brain) loses all ability to distinguish flicker or lag.

No argument there

What I wonder is if the distortion you are seeing would lessen, or go away, if you can force it to receive at 72Hz (again, I don't know exactly what model you have, but I've read those Panny's can do it).  If it is caused not really because of the mismatch between 24fps and 50hz, but because 50hz isn't high enough to hide the distortion from your eyes (which are probably pretty good)!

My eyes are OK but the proof is in the pudding, changing the refresh rate works!  While I'm happy to be corrected I've never heard of a defined 72hz or 120hz based consumer video standard (eg 1080p/72, 1080p/120hz) so I'd be surprised to see that any CE devices are capable of such (the 72hz is an internal processing thing to avoid flicker from a 24p source).  The http://en.wikipedia.org/wiki/1080p link is very simplistic but the bottom table does allign with my understanding of what the video standards are supported....

Over to you (if you ever sleep)!
Thanks
Nathan

[jmone]

Ok here is a far more eloquent version of what I'm trying to describe from http://whatsonhdtv.blogspot.com/2006/05/1080p-from-high-definition-dvds.html (bold is mine).

What if the TV can only display 1080p at 30 fps or 60 fps, not at 24 fps, and what's on the disc is 1080p/24? Then either the player or the TV (typically the player) must perform a conversion. Again, as with any type of scan conversion, there is a potential for visible artifacts to result.

In this situation, the main reason for artifacting is that 60 is not an even multiple of 24. Neither is 30, for that matter. If 1080p/24 on DVD is converted to 1080p/60, or 1080p/30, or even 1080i/60, some frames in the output video will necessarily be interdigitated hybrids of two source frames, which can lead to ragged edges on moving objects. Or else the 24 input frames per second will be parceled out to varying numbers of output frames, some to one and others to two, making for jerky motion.

To avoid such motion artifacts, the TV ought to be able to operate at a 1080p frame rate that is an exact multiple of what's on the disc: say, 72 fps. 48 fps would work, too. And incidentally, the rate at which the TV "paints" frames on the screen is its "refresh rate," and is stated in Hertz or cycles per second. 48 frames per second is 48 Hz. 72 fps is 72 Hz.

A 24-Hz refresh rate with a one-to-one correspondence of output frames to incoming 1080p/24 frames would not work well, unfortunately. It would produce annoying flicker on any bright video display screen. (The reasoning is similar to why motion pictures are projected with each frame illuminated twice in 1/24 of a second.)

Ideally, the player would supply the TV with 1080p/24, and the TV could convert it to, say, 1080p/72 (or 1080p/48) to avoid the flicker common when bright video displays use a 24-fps refresh rate. The conversion from 24 to 72 frames per second is straightforward and does not produce visible artifacts.