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Lumagen VisionDVI confusion.

Discussion in 'Projectors, Screens & Video Processors' started by Canoehq, Jun 2, 2005.

  1. Canoehq

    Canoehq
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    I’m about to embark on a new plasma purchase, a Pioneer 50MXE1, but before I hand over the cheque, just want to double check something about my scaler, so would be really grateful for some help here !

    I’ve been quietly collecting some nearly new bits of kit for a few months now and so far, have a Lumagen Vision DVI and a Dtronics DVI splitter (to give the new MXE1 some extra ***cough*** functionality ;) ;) ) all sitting in a box ready to go. From my reading here, I think all of these bits should work well with the Pio.

    However, what I need to know relates to film detection / 1080p deinterlacing, which I know is not something handled by the Vision DVI nor is it likely to be via future upgrades.

    But as we tend to watch a lot of SKY (esp footy) in our house rather than DVD’s, should I worry about the VisionDVI not being able to offer this higher level of deinterlacing (bearing in mind the Pio’s native is only 1280x768) or have I missed a trick here and should upgrade to a HDP ? Basically, what programming is on it's way that I will need 1080p for and will my Pio be able to display it if I did upgrade to a HDP.....or should I just stick with the DVI ?

    (Have also obviously based my plans on Sky HD being 720p / 1080i or have I got that wrong as well !!)

    Cheers for all or any help with this. :smashin:
     
  2. kurtz

    kurtz
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    I think you're confusing program source with scaler output. I don't think there's any 1080p source imminent - 720p and 1080i will be the Sky HD standards.

    The extra 'oomph' an HDP offers is to deinterlace 1080i - or scale a lesser source - to 1080p output. The 1080p output would presumably be fed to some 1080 line native device (like a Qualia projector).

    Your 50" MXE-1 would be a 768x1280 native device, so you would use the scaler to output 768x1280.

    So I'd reckon it would need to handle:
    • 480i deinterlacing and scaling to 768x1280 (for NTSC DVD)
    • 576i deinterlacing and scaling to 768x1280 (for PAL DVD and current Sky)
    • 720p scaling to 768x1280 (for future Sky HD)
    • 1080i deinterlacing and scaling down to 768x1280 (for future Sky HD)

    Therefore the VisionDVI just needs to be able to output 768x1280 @ 50Hz and 60Hz - and I think it can just manage that because on page 1 of the manual it says the VisionDVI goes up to 768p (which is 768x1366 so it would have bandwidth to spare).
     
  3. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Kurtz has got it.

    As for the 1080i to 1080p film detection. The footie is likely to be broadcast by Sky at 720P so no need for that, at least on their Sports channels.

    Gordon
     
  4. Canoehq

    Canoehq
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    Ah, the mists are clearing !

    Thanks guys for the help, but to finalise things, let me see if I have got things right with these final quick Q’s

    1. Would I be right in thinking that a 1080p output from a HDP (scaled down to 768p by the MXE1) would somehow be a significantly higher pq than if the plasma was fed 768p native by the VisionDVI …..or am I just chasing diminishing returns and, as an average punter, probably wouldn’t notice the difference ?

    2. Again, would 768p out of a HDP be significantly better than 768p out of a DVI or is the difference just a few % at the top end which, while nice to have, is not really a huge step up ?

    3. In not having 1080i/1080p film detection, what will I be missing by staying with the DVI. How will this show itself on the VisionDVI or is there a simple workround I could use ?

    4. Finally, am I being shortsighted in staying with the DVI. For example, is 720p just a temporary resting place ahead of a general industry wide move to 1080p or do I not need to build in some headroom this early?

    Again, huge thanks for any help you can give me.

    Cheers
     
  5. Joe Fernand

    Joe Fernand
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    Canoehq

    With the MXE1 the best results are achieved when you set the Video Processor to output a 'Native' signal at 1280x768 and then ensure the display is not over or under scanning the image; many folk call this 1:1 pixel mapping.

    Your not going to see a 1080P Broadcast source for a long time yet - the Infrastructure costs to the Broadcasters will keep that at bay for a while yet.

    With the most recent Firmware updates were starting to 'see' the difference between the capabilities of the VisionDVI and VisionHDP - that's not to say your DVI is poor or needs replacing just that you can now A-B them and 'see' differences.

    Best regards

    Joe
     
  6. kurtz

    kurtz
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    Canoehq,

    Your Q1 may be theoretical because I don't think the MXE-1 can input 1080p in the first place, but even if it could you would be tampering with one of the basic rules of picture quality which is to have as few steps in the video chain as needed; just stick with a few quality components and cables. In your example you would be using the HDP to upscale the signal to 1080p (from 480/576/720 anyway) only to have the Pioneer chuck away over 300 lines worth of it! Minimise the amount of A/D, D/A conversion and rescaling to preserve as much of the original picture as possible. I would think its best to try and keep it a 'one-stop shop' and let the Lumagen do the deinterlacing and scaling in one place.

    Your second question is harder because the HDP has more horsepower available for enhancement. (I have an HDP). Certainly when they implemented the sharpness filter and early 10bit datapath on the HDP (don't think they've done it on the VisionDVI) they made a noticable improvement. I think there's more 10bit developments to come amongst others so things may get even better. Gordon may be able to comment on future development plans for the VisionDVI vs. the HDP. There's more to picture quality than resolution - such as retention of detail when scaling or minimising colour banding and so on.

    By not being able to output 1080p from your scaler, you're not going to miss out on anything unless you buy a 1080 line (or more) display that can accept 1080p.

    In terms of 720 lines being a temporary resting place, there will certainly be 1080 line and higher resolution displays out in the future. It's a question of whether you envisage buying one in the next few years. If not, the VisionDVI will handle the MXE-1 fine.

    As far as "short-sighted" goes, that's a bit harsh on yourself; it's more unquantifiable because of the potential improvements to the HDP. I'm not really up with what's on the horizon; all I can say is the sharpness/10bit software release back in April brought a smile to my face. The change probably was a few percent, so it depends how hard you're looking. Unless you can objectively compare "before-and-after" frames you end up talking in subjective terms like an audiophile referring to "depth", "clarity", "solidity", "smoothness" etc. I can't do that, all I can say is that it was like at Event II when Nic Rhodes was showing us different scalers back to back with the same scenes and you could spot the differences. You'd need to judge for yourself - but don't beat yourself up for having a Lumagen DVI!
     
  7. Canoehq

    Canoehq
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    Sincere thanks to everyone. Pro's and con's are now extremely clear to me now, so will go away and have a think !

    Thanks again.
     
  8. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Just to add some stuff here.

    DVI: The basic architecture of the HDP and DVI are the same so there are improvements to the HDP which may affect DVI. The last firmware release was one. The 10 bit path wont happen on the DVI so when future enhancements come to HDP with that on board the difference in image quality will probably be even more noticeable. As KURTZ says though until the first of the 10 bIt stuff went in there was essentially no difference between them....and they weren't shabby then!

    Next up I believe is GENLOCK and all models will benefit from that. The 1080i film detection will be beneficial for outputting at ALL resolutions, not just 1080P. The benefits of reconstructing the original 1080line frame and downscaling to 768P should be obvious with film material over the simple methods used in displays and many scalers currently (incl DVI).

    The DVI is ideal for current plasma and fixed pixel displays. The HDP is more futureproofed and will most likely be beneficial with the inevitable 1080P resolution displays we'll see over next 2-3 years.

    Gordon
     

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