[VirusKiller]

I hope this post doesn't contravene any forum rule, but I just noticed the following on Gordon's website:

Convergent AV - Audio / Visual / Consultancy - SCALER AMNESTY

"£1000 trade in on any DVDO/ABT, PMS or Lumagen scaler against a new Radiance XD."

I have no connection with Gordon, other than being a happy customer.

[movie_fan]

Anyone needing a VP30?

[eiren]

Must... resist...

Would that also include a DVDO EDGE?

[VirusKiller]

Last I heard, the DVDO Edge was made by DVDO

[eiren]

You're right, it does say ANY DVDO processor

[Eitzel]

I use a Radiance (that I bought through Gordon) and it is a wonderful piece of kit. I wouldn't be without it.

[movie_fan]

Originally Posted by Eitzel

I use a Radiance (that I bought through Gordon) and it is a wonderful piece of kit. I wouldn't be without it.

And this trade-in program makes up for a complete bargain.

[Gordon @ Convergent AV]

Originally Posted by eiren

Must... resist...

Would that also include a DVDO EDGE?

Yep, any scaler...the old line doublers probably not but any of the others. Go on...you know you want to !

[eiren]

Ahhh too tempting... but I love that EDGE processor too much to swap it. Would like to have both though.

[Liam @ Prog AV]

Buy another one for £599, then trade it in for £1000!!! We're doing the offer too, I'm just too lazy to get the website up-to-date.

[Roland @ B4]

Any one rember the Cheese video box?

I'll try gordon for one of those as a trade in

[TopMeTom]

The XD is £3700!!!!

Wow, that's a lot of dosh.......

[Jackass]

Is the XD not HDMI 1.3 capable?

if so then the radiance would be last in the chain before the display?

For this type of money, i'd expect HDMI 1.3

[binbag]

Anyone care to make me an offer on my still in use I-scan HD?

TBF: Lenexpo have always said they'll honour the DVDO trade-in policy if I cover the postage back to the USA.

[Avi]

Originally Posted by Jackass

Is the XD not HDMI 1.3 capable?

if so then the radiance would be last in the chain before the display?

For this type of money, i'd expect HDMI 1.3

Well really we need HDMI 1.4. HDMI 1.3 just isn't good enough anymore.

The XE uses HDMI 1.3 Tx/RX chips but unfortunately there isn't any movie source material i.e. Blu-ray, DVD etc that can provides more real data. Sill may be usefull if you want to witch bitstream HD audio I guess.

AVI

[Gordon @ Convergent AV]

The hdmi 1.3 is as AVI says a pretty pointless thing for the vast majority of folk and is purely marketing lead rather than for any realworld benefit

XD has "virtual input" capability. This means, that should you want to send HD audio undecoded from your multiple HD sources, or for any other reason, you could send 6 hdmi sources direct to your amplifier, put it on pass through and then send the video out to ONE input of the XD. You could then tell the XD that when input 2 command is received it shoulD do all the colour correction, scaling, de-interlacing and image enhancement assigned to INPUT2 but it should actually look at input1 for the video signal. The same for inputs 3,4,5,6....so actually even without 1.3hdmi it's a very, very powerful product beyond any of its competitors.

Here's a quote from a crystallio3 owner who just got an XD...

Yesterday, I tested the radianceXD in 576i and 1080p24 versus Crystalio II 3100.
The winner is : radianceXD. I have never seen such a picture quality both in SD and HD
I'm very very amazed by its performances and its manufacturing quality. LUMAGEN seems to be the best in the world of scalers.

[andrewfee]

Originally Posted by Avi

…
unfortunately there isn't any movie source material i.e. Blu-ray, DVD etc that can provides more real data. Sill may be usefull if you want to witch bitstream HD audio I guess.

It's my understanding that Blu-ray is stored as 8-bit 4:2:0 YCC data. You cannot transmit 4:2:0 data over HDMI, it must be upscaled to a minimum of 8-bit 4:2:2 YCC.

Most (all?) displays use RGB pixels, so this data must end up as 4:4:4 RGB data in the end to be shown on the screen. (whether that is sent to the screen or if it has to do the conversion internally)

It is much better to only perform one scaling/conversion operation, so you ideally want to go from 4:2:0 data directly to 4:4:4, rather than 4:2:0 > 4:2:2 > 4:4:4.

Scaling always results in more data than you began with and requires a higher bit-depth than you started with to avoid introducing artefacts due to rounding.

The most basic example I can think of is this. You have a 4:2:0 video—this means that you only have one colour sample for every four pixels. (2x2)

So while your luma information is 1920x1080, your chroma information is 960x540 and must be upscaled.

To keep things simple, lets say you just had a red image. The red value of one sample is 200, and the next sample is 201.

When you upscale that you need to interpolate between the two points creating an intermediate pixel. In this case, that pixel would have a red value of 200.5 (halfway between 200 and 201)

But you can't have 200.5 —it must be a whole number. So if that scaling was done in 8-bit, your three final values would be 200; 201; 201 because 200.5 has to be rounded.

If you were to do the processing in 10-bit instead of 8-bit however, that gives your four times as many steps of gradation. So your 256 steps become 1024 steps. 200 becomes 800, 201 becomes 804.

With that extra precision, your intermediate value is now a whole number, so you would end up with 800; 802; 804, rather than having duplicated values which show up as banding/posterisation.


So upscaling alone requires greater than 8-bit precision, and must be performed on all Blu-ray content. (at a minimum, going from the stored 4:2:0 data to 4:2:2)

The highest quality signals HDMI without deep colour (pre-1.3) can transmit are:

4:2:2 YCC 12-bit
4:4:4 YCC 8-bit
4:4:4 RGB 8-bit

This means you can either send 4:2:2 YCC data at 12-bit (only half of the upscaling done) or you need to throw away data and output at 8-bit 4:4:4 in either RGB or YCC.

If you want to perform all the required upscaling in a single step and retain all precision, deep colour is necessary as it allows 4:4:4 signals to be transmitted with up to 16-bit precision.


In addition to upscaling the 4:2:0 data, you have to convert it from YCC to RGB at some point. From what I've read, this requires at least 16-bit precision to avoid doing any rounding.

So while you may start with 8-bit YCC data on a Blu-ray disc, it ends up as 16-bit RGB data if you keep things at full precision without any rounding to avoid introducing artefacts.



From my own experience, I would say that the YCC to RGB conversion is the most critical step, as it seems to be the most likely to introduce posterisation into the image if there is not enough precision.

Most displays' internal processing only seems to be 10-bit. I am not convinced that this is enough to properly handle the YCC > RGB conversion without noticeably introducing posterisation, so I would prefer not to send YCC to a display at all.

What seems to produce much better results is if you have a source capable of greater than 10-bit processing do the YCC > RGB conversion, and then properly dither the result to the maximum bit-depth supported by the display panel.


So having something perform the YCC to RGB conversion in 16-bit then dithering that result to 10-bit RGB should look much better than sending 12-bit YCC and having the display do the conversion to RGB internally.



Whether or not you need deep colour support depends a lot on what your video chain is like. If you have a standalone player > video processor > display, I absolutely would want deep colour support.

I'd want to output the highest bit-depth 4:4:4 YCC I can from the source player, have the video processor then do the conversion to RGB (assuming it does this with more precision than the player) and send the best quality RGB to my display.


In my case, I don't actually need deep colour though. I use a HTPC running MadVR which takes the 8-bit 4:2:0 YCC data, converts that to 16-bit 4:4:4 RGB data internally, and then outputs it as a properly dithered 8-bit RGB signal.

The reason I don't need deep colour is because the high bit-depth stages of processing are all done inside the PC, rather than passing them down the line to another device, and I get a dithered 8-bit output from it which goes straight to my display. (this looks better than the output of any stand-alone Blu-ray player I've seen as none of them use 16-bit internal processing)

That's not to say that deep colour wouldn't be beneficial though. PCs can't really output more than 8-bit right now, and outputting 10,12 or 16-bit would mean less dithering was required. (which can add a slight amount of ‘noise’ to the image, but it's negligible in my opinion)



So depending on your display chain, deep colour may or may not be necessary. Processing greater than 8-bit absolutely is necessary, however, and depending on what devices you are using and how capable they are, deep colour may be necessary to retain as much precision from the source all the way to the display and do the best quality conversions. If you don't have deep colour, you may be losing precision before important processing stages are performed. (such as the YCC > RGB conversion)



Whether or not deep colour is of importance to the Radiance is another thing as well. I don't know about the XE—I had an XD a while ago and returned it partly because it downconverted any input to 4:2:2. (an unacceptable loss of image quality in my opinion)

If the XE still does this (and I have no reason to think otherwise, as I believe it's just the input boards that changed and not the internal processing) then that instantly removes virtually any benefit that could be had from supporting deep colour inputs as you may as well just send 12-bit 4:2:2 YCC which any version of HDMI supports. (though, depending on the internal processing you could potentially have greater than 12-bit 4:2:2, but I don't think that's the case either)

Even if it does convert all inputs to 4:2:2, there may still be some benefit to be had from having the radiance do the YCC > RGB conversion and outputting 10-bit or greater RGB to your display which you wouldn't get with an XD. But again, that's something that may or may not be an improvement depending on your setup.


Taking things a step further from that, even if you do output greater than 8-bit from the source to your display, whether or not that ends up being visible is another thing. I have yet to see any modern display (Plasma, LCD, DLP, LCoS etc.) even match up to the quality of gradations you get sending 8-bit RGB to a CRT. They all posterise the image to some degree regardless of what bit-depth you send them. (that doesn't necessarily mean they won't posterise the image less with a better input though)

[VirusKiller]

There's some truth in what you are saying Andrew, but I think you over-estimate the importance of outputting more than 8 bits from the source. Chroma is at lower resolution on disc for a reason: The eye is not as sensitive to it, spatially, than luma. Rounding errors in 4:2:0 to 4:2:2 conversions are probably not noticable as long as the upsampling is done competently (i.e. no CUE) and, strictly, the source could use dither to prevent such errors in an 8-bit signal.

Also, most displays these days, from what I've seen, down-convert from 4:4:4 to 4:2:2 for internal processing, so I try and keep everything at 4:2:2 for as long as possible and send 10-bit 4:2:2 from my XD to my display.

Also, you should be using the term "chroma upsamping" rather than "upscaling".

[choddo2006]

Originally Posted by Gordon @ Convergent AV

XD has "virtual input" capability. This means, that should you want to send HD audio undecoded from your multiple HD sources, or for any other reason, you could send 6 hdmi sources direct to your amplifier, put it on pass through and then send the video out to ONE input of the XD. You could then tell the XD that when input 2 command is received it shoulD do all the colour correction, scaling, de-interlacing and image enhancement assigned to INPUT2 but it should actually look at input1 for the video signal.

That is very neat.

[choddo2006]

Originally Posted by andrewfee

Loooooong post.

I'm not sure that's true.

If you're going to upsample the colour, it doesn't really matter if it was input as 8bit, 10bit or 16bit - they all are effectively the same thing (if you started with an 8bit source) until you start interpolating.

[Avi]

Originally Posted by andrewfee

It's my understanding that Blu-ray is stored as 8-bit 4:2:0 YCC data. You cannot transmit 4:2:0 data over HDMI, it must be upscaled to a minimum of 8-bit 4:2:2 YCC.

Most (all?) displays use RGB pixels, so this data must end up as 4:4:4 RGB data in the end to be shown on the screen. (whether that is sent to the screen or if it has to do the conversion internally)

I think it really depends on the display. What happens if the display truncates the input bit depth and converts to YCbCr 4:2:2 for internal processing prior to converting to RGB. Other products such as the DVDO Edge do this.

I've observed a reduction in chroma resolution using the Spears & Munsil chroma test when using 4:4:4 input compared to 4:2:2 input. I think other have also reported similar using different combinations of products.

Originally Posted by andrewfee

Whether or not deep colour is of importance to the Radiance is another thing as well. I don't know about the XE—I had an XD a while ago and returned it partly because it downconverted any input to 4:2:2. (an unacceptable loss of image quality in my opinion)

Interesting given the Edge also converts all input formats to YCbCr 4:2:2. Do you no longer use the Edge for this reason ?

AVI

[Gordon @ Convergent AV]

The plan is at some point to add the game mode pass through so that if you had a 4:4:4 source it would bypass the genum and go straight through the Lumagen processing. So the issue Andrew has will not exist

[andrewfee]

Originally Posted by VirusKiller

There's some truth in what you are saying Andrew, but I think you over-estimate the importance of outputting more than 8 bits from the source. Chroma is at lower resolution on disc for a reason: The eye is not as sensitive to it, spatially, than luma. Rounding errors in 4:2:0 to 4:2:2 conversions are probably not noticable as long as the upsampling is done competently (i.e. no CUE) and, strictly, the source could use dither to prevent such errors in an 8-bit signal.

Also, most displays these days, from what I've seen, down-convert from 4:4:4 to 4:2:2 for internal processing, so I try and keep everything at 4:2:2 for as long as possible and send 10-bit 4:2:2 from my XD to my display.

Also, you should be using the term "chroma upsamping" rather than "upscaling".

I would have used chroma upsampling but thought it might be easier for people to understand if I say colour is 960x540 when the black & white info is full resolution and that it needs upscaled.

All of my displays show 4:4:4, and if I send them RGB it's untouched, as far as I'm aware. (I may be wrong with my Sony projector though—I don't know if RCP is done in RGB or YCC, but it is still 4:4:4)

With video it's a lot less problematic (though what's the point in something like madVR if a VP is going to undo its good work) but with computer generated stuff it's very noticeable when a display doesn't process in 4:4:4 or a VP downsamples to 4:2:2.


And you're absolutely right—if the display is processing internally with 4:2:2 then there's probably no benefit to be had from deep colour at all. (unless you're potentially ending up with 16-bit 4:2:2 signal rather than 12-bit but that's extremely unlikely)

Originally Posted by choddo2006

I'm not sure that's true.

If you're going to upsample the colour, it doesn't really matter if it was input as 8bit, 10bit or 16bit - they all are effectively the same thing (if you started with an 8bit source) until you start interpolating.

That's exactly my point though—you have to do interpolation because chroma is effectively a quarter the resolution of luma.

It's not simply a case of simply taking what's off the disc and showing it on the screen without doing anything.

Same thing applies to the YCC > RGB conversion, which also has to be done at some point. (assuming the display has RGB subpixels) That needs much more than 8-bit to avoid rounding.

You can dither the result and output 8-bit—which looks great if it's done properly—but most devices just seem to use rounding or do a bad job of it which results in posterisation.

Originally Posted by Avi

I think it really depends on the display. What happens if the display truncates the input bit depth and converts to YCbCr 4:2:2 for internal processing prior to converting to RGB. Other products such as the DVDO Edge do this.

Well then there's absolutely no point to deep colour with that display/device. In a best-case scenario, deep colour will improve things—or at the very least, it will avoid degradation until it reaches the display.

Whether or not it would provide a benefit to your display chain is another matter entirely. It's not simply a case of deep colour = better picture. My point is that there absolutely is a reason for deep colour, even if our sources are stored as 8-bit 4:2:0 YCC, and that it can potentially improve things if you have the right setup for it.

Originally Posted by Avi

Interesting given the Edge also converts all input formats to YCbCr 4:2:2. Do you no longer use the Edge for this reason ?

The only thing I have hooked up to my EDGE now is my Topfield PVR via an RGB + Sync connection. The OSD suffers from the 4:2:2 processing, but not the actual picture. One of the benefits is that the EDGE converts the optical audio to HDMI which makes cabling a lot easier.

That said, I've all but eliminated using the EDGE now. I tend to transfer recordings off the PVR via USB and play them back on the HTPC at 24fps instead to get around the PAL speedup.

[Avi]

Originally Posted by andrewfee

I My point is that there absolutely is a reason for deep colour, even if our sources are stored as 8-bit 4:2:0 YCC, and that it can potentially improve things if you have the right setup for it.

I understood your point. My point is simply that HDMI 1.3 can tx/rx an RGB/4:4:4 at higher than 8 bit precision which may be beneficial in some circumstances. What isn't clear is what a HDMI 1.3 equipped display does after it receives a higher than 8 bit input hence my point about it depends on the display. We know what some products like the Edge do based on info from ABT but I've seen very little from display manufacturers that confirm what happens to the signal once it leaves the HDMI receiver.

AVI

[FrazerT]

Alternative for consideration, sell existing scaler & pick up a used Radiance XD: http://www.avforums.com/forums/tv-pr...processor.html

[Chris5]

Getting back on topic, if your input is SD from a SkyHD box, which produces a superior output, a VP50+Prep or XD?

Thanks in advance.

[Liam @ Prog AV]

VP50 does a better job of deinterlacing from HDMI source purely because it can attain the original fields using PREP which Lumagen does not have. However with say an RGB scart connection the deinterlacing in the Lumagen is equally good I would say, but does mean a softened image.

Upscaling though is clearly better on the Lumagen. With mine I have HDMI and scart connected and use 576p HDMI for idle SD watching and flick it over to RGB Scart when I see the material is being deinterlaced badly by the Sky box and it bothers me enough to reach for the remote!

[Chris5]

Hi Liam,

So if you only ever feed your processor an HDMI feed from skyHD or 1080P24 from bluray, picture quality wise, its not worth upgrading from vp50 to XD?

[Liam @ Prog AV]

The 1080p24 from Blu-Ray will not be being deinterlaced or scaled, but the SD channels from Sky will be upscaled much better. However you have to remember it's not just these two elements in the video processor, even without a professional calibration to make use of the colour management and gamma tracking you will have y/c adjustment, genlock, frame lock, chroma error correction, correct colourspace conversion etc etc.

[Avi]

Originally Posted by Chris5

Getting back on topic, if your input is SD from a SkyHD box, which produces a superior output, a VP50+Prep or XD?

Thanks in advance.

The Radiance can't fix deinterlacing errors that exist in a signal converted to progressive prior to input. SD interlaced output option over HDMI isn't supported by the SkyHD box so you're at the mercy of its deinteralacing if you use HDMI for SD.

It's difficult to answer your output question directly because "superior output" may also involve different factors depending on the requirement for example correcting colour gamut or grayscale issues that can't be fully calibrated on the display. "Superior" may also depend on your scaling preference with regard to characteristics of the different algorithms used.

I use both the Radiance and DVDO product and IMO they offer difference things.

AVI