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Lumagen stutter on pans...

Discussion in 'Projectors, Screens & Video Processors' started by SimonO, Nov 11, 2003.

  1. SimonO

    SimonO
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    Hello Gordon...

    Many thanks again for a fantastic day on Saturday... I was really interested in the MXE/Lumagen demo as I'm trying to decide which 50" plasma/processor to go for (95% R2 PAL disc collection)...

    How was the Lumagen set up on the MXE and why was there stuttering on the pans (I didn't see it on the other MXE)..? In all other respects I thought the Lumagen was incredible, especially for the money..!

    [Edited due to incorrect use of terminology - judder not stutter :lesson: ]

    [Edited again due to incorrect use of terminology - stutter not judder..! :suicide: ]
     
  2. Jeff

    Jeff
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    Hi Simon,

    There was good reason for it, but I'll let Gordon fill you in with the details, you were right the first time, what you saw was essentially stutter not judder.

    Jeff
     
  3. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Hi Guys,

    Took a long time to get through all these threads but here I am.

    With any display and source you have to compromise somewhere. The stutter was due to teh fact I set the scaler to output 1080P@60Hz from an incoming signal of 576i@50Hz. Frame rate conversion from 50 to 60 is what caused it.

    Why did I do it though is another interesting question. Well, because if you go on to a MXE at 768P@50 it thinks it's a PC signal and does it's own frame rate conversion up to around 7X Hz. This causes tearing in image at times and is VERY noticeable on that long pan shot. In normal use that stutter is hardly seen. Unfortunately that pan really shows it up. Given time (and I set that demo up around 9.00am on Saturday morning!) we would have tried some other resoltuions and refresh rates.

    Cheers,

    Gordon
     
  4. Dutch

    Dutch
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    Hi Gordon,

    Is it possible to have the Lumagen output a 1080p/50Hz signal from a 576i/50Hz incoming signal? Wouldn't that get away from the 50 to 60 frame rate conversion?

    One more thing, any news on my Lumagen, yet? ;)

    Steve
     
  5. SimonO

    SimonO
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    Thanks Gordon...

    So the stutter seen was a product of 25fps being shown 60 times per second rather than a multiple of 25..? If so why not use a 75Hz refresh rate..? Or is that what the MXE doesn't like..?

    The reason I ask is that I've been looking at the supported refresh rates on the new Panasonic 50" and it looks like it will do no more than 60Hz and it's 'quasi 100Hz' feature, I assume, kicks in at 50Hz, so not much room to manoeuvre (not sure I fully understand the 100Hz thing but from what I can see it will reduce grey scale..?)...

    I was going to wait to see if the new MXE supports 75Hz, however from what you have said this may not work...

    I'm convinced that the Lumagen is the way to go... Just not sure which is the most suitable plasma.!?

    Obviously I understand if you don't want to get into which plasma you prefer, however you could explain which is technically better suited to the Lumagen...

    PS I'm stuck with plasma for 'family' reasons so please don't suggest the PJ route 'cos I'll just get depressed..!

    Cheers...

    Simon
     
  6. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The problem with 50Hz at most resolutions is that many plasma's will not allow you to get geometry correct (even using a combination of Lumagen and panel sizing) . Pioneer plasma's seem to only NOT do refresh rate conversion internally if fed NTSC, PAL or ATSC HD rates. As I say, I happened to use a clip that really shows up panning issue. I could have played a clip form Bourne Identity and no-one would ever have mentioned anything.


    DUTCH. It arrived today and I am trying to contact your supplier to get it to him...or you.

    The Pannies are most forgiving in regard to this issue (afaik so far) I'm going to order a D6 for myself but not sure whether to go HD or SD.....

    Gordon
     
  7. Dutch

    Dutch
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    Cheers, Gordon. Looking forward to it! :smoke:

    Steve
     
  8. SimonO

    SimonO
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    Thanks Gordon...

    I'm not bashing your demo, I'm glad you showed the clip... Like I said, I thought the Lumagen was fantastic and I preferred the direct Panasonic 50" to the 503MXE (I preferred all the 'softer' looking demos rather than the SDI stuff, possibly due to the panel/projectors rather than the source/processing..?)...

    Okay, if you are going for the Panasonic, what about the 'quasi 100Hz' on all 50Hz stuff and the 60 Hz maximum refresh rate..?

    Maybe I'll just wait for you to play with it... Please get one soon..!

    Cheers...

    Simon
     
  9. SimonO

    SimonO
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    Out of interest, why can't you do 768p @ 75Hz into the Pioneer for PAL stuff..? This wouldn't add any frames would it..?

    Please tell me if I'm way off track here..!
     
  10. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The issue with 75Hz is that the panel MUST recognise the signal to show it. Then once recognised you need to be able to adjust the geometry to make things correct shape (which is often not possible). Also as I have said with an MXE it will just try and convert this back to it's native refresh of around 70Hz...creating more artifacts.

    Then there is the fact that by going at 75Hz you are trying to create a 3:3:3:3 sequence. However with anything bar a Rock or HTPC just now (and they may not even do this all the time) you might get, 3:3:2:4:2:4:3:3:2:4...resulting in judder again

    It's a tricky business this scaling lark!
     
  11. SimonO

    SimonO
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    This is good stuff... So basically both the Panasonic and Pioneer try to return everything back to 60 and 70Hz respectively (presumeably why I see flicker on the Panasonic and not on the Pioneer..?), neither being that great for PAL... And even if they could do 75Hz at their native resolution, the processor may struggle to do it anyway..?

    So it's seven of one, half a dozen of the other...

    Am I correct in saying that the Panasonic, fed with anything other than 50Hz will disable the 'quasi 100Hz'..?

    Sorry to bang on, but if the 04 MXE works like the current MXE, I might just go for the Panasonic now (even with the dodgy DVI card)... Agree..?

    Cheers...

    Simon
     
  12. SimonO

    SimonO
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    Thinking about it, if the new HDE does 75Hz for PAL then there is a chance that the 04 MXE will also... Maybe I will wait... But then the processor might not do 3:3:3 reliably...

    Oh I don't know... I think I'll just wait to see what Gordon does..!

    tbrar... I've just upgraded my 14" to a 21"... :smoke:
     
  13. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    I hope to have my D6 next week. Will know more when I have mine. I'll get a DVI card as well I suppose to test.

    Gordon
     
  14. SimonO

    SimonO
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    SD or HD..?
     
  15. Gordon @ Convergent AV

    Gordon @ Convergent AV
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  16. SimonO

    SimonO
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    Okay, I've done some more geek'in... Am I right in saying that the Lumagen does an okay job of the 50Hz to 60Hz conversion and therefore, though not ideal, should work well with the Panasonics 60Hz internal rate..?

    I'm just trying to talk myself into the Panasonic 'cos the picture was much better than the MXE IMO...
     
  17. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    I'm going to try a few resolutions on Panny at 50Hz. Remember that Lumagen can auto load different resolutions on the fly for PAL and NTSC. So a starting point would be 576P@50 for PAL and then 720@59.94 for NTSC. Then I'll start upping output res to see what is achievable. Hope to have my own D6 on Monday or Tuesday.

    G
     
  18. SimonO

    SimonO
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    That will be interesting, but won't 50Hz kick in the Panasonic's 'Quasi 100Hz' circuit..? May not be a bad thing for stutter etc., but doesn't this circuit reduce grey scale..?

    Actually the original reason I started looking at refresh rates was that I really suffer with 50Hz on a CRT TV (it gives me a headache after a while)... It's also the reason I was so anti Panasonic (pre Event II), as the flicker on the 5 series I assume is down to the panel running at 50Hz on PAL..?

    Can't wait to see what you get... Maybe I'll have a plasma for Christmas after all..!
     
  19. Gordon @ Convergent AV

    Gordon @ Convergent AV
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  20. SimonO

    SimonO
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    Waiting patiently... ;)
     
  21. SimonO

    SimonO
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    ... :smoke:
     
  22. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Simon,

    I've got my D6. I am going to play with DVI, rgbhv refresh rates and resolutions today.

    Gordon
     
  23. SimonO

    SimonO
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    ... :) :smoke:
     
  24. Nic Rhodes

    Nic Rhodes
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    I thought you want the Pioneer, Melanie won then ;)
     
  25. Gordon @ Convergent AV

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    No, other way around. She wanted Pioneer and I wanted Panny. Of course I've just broken my feed from SkyPlus box so I'm having to do some soldering.

    G
     
  26. SimonO

    SimonO
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    ... :cool: :smoke:
     
  27. SimonO

    SimonO
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    Is it so good that you just can't tear yourself away, or are you still fixing the Sky+..? ;)
     
  28. Gordon @ Convergent AV

    Gordon @ Convergent AV
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  29. SimonO

    SimonO
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    Yes, thanks... Did you get mine..?
     
  30. Cool-hand

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    Hi

    Can you easily switch the lumagen between 50hz output and 60hz output via the remote, or even better, can it autodetect an incoming signal via component or sdi and then switch?

    Thanks

    CH
     

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