Hi everyone, yesterday I've finally got my first Zidoo product, a Z9S. Setup was incredibly easy, and most things worked fine out of the box, even better than I expected... but HDR movies look absolutely horrible: washed out, very dark, with a yellowish tint. My Z9S is hooked to a projector, a Sony VW500ES. It's a native 4k projector, but it's quite "old": no HDR, only bt.709 color space. I've bought the Z9S 'cause I knew it could do an excellent HDR to SDR conversion, but it seems something's wrong here. Pre-converted movies in SDR, both X264 8bit and X265 10bit, work absolutely fine. My firmware is 2.2.82; I've tried most combinations of Deep Color Mode (but only Auto and Priority 8bit work); HDMI is set on Auto; I've tried all Color Space Modes; both Mode HDMI (16.235 and 0-255); all HDR options (including Auto and SDR Rec.709, which I guess should work with my projector). Just to make sure it wasn't my HDMI 2.0 cable's fault, I've used the short one included in the box, but still no luck. I really don't know what to do anymore, unless it can be fixed with a firmware update (but I don't want to update yet, unless it's absolutely crucial). Maybe I'm missing something here, like a particular combination of settings? Thanks a lot in advance!
Thanks, I'll try as soon as I can. The only option I see with Rec.2020 is under HDR -> "SDR Rec.2020", I guess you're referring to this one? In the HDR to SDR menu I can only choose the Gamma.
Tried (once with deep color mode Auto, once with Priority 8bit), didn't work. All HDR options give me the same result. P.S. Just to leave no stone unturned, I've tried enabling all Color Space Mode priorities (RGB 444, YCbCr 422 and 444, YCrCb 420) on both HDR -> SDR Rec.709 and SDR Rec.2020. No change at all.
>Just to make sure it wasn't my HDMI 2.0 cable's fault, I've used the short one included in the box, but still no luck. This could be the issue, the HDMI cable that comes with the z9S is absolute rubbish and defective, causing problems in my case. try to use a decent one instead.
I wouldn't say that the Zidoo HDR>SDR conversion is excellent, but it's not bad although it does suffer from a certain amount of posterisation. Your description of “washed out” would usually apply to viewing HDR content on an SDR monitor – this would be due to trying to view a wide colour gamut (BT.2020) inside a narrower gamut (BT.709) – so colours look washed out, almost monochrome. You also say the image is dark – this would usually be a gamma issue. Gamma is the how luminance (brightness) is mapped input to output So, when the Zidoo converts HDR to SDR, it does two things: 1. It converts the BT.2020 colour space into a smaller BT.709 colour space. It does this quite well. So red is still red, blue still blue etc there are just not as many hues in between – I certainly wouldn’t call the conversion “washed out”. Slightly inaccurate maybe, but certainly not washed out and as I said there is a certain amount of posterisation which is really dependent on the source material encoding. 2. It converts the PQ encoded ST.2084 gamma curve of the HDR encode into a standard power gamma such as any SDR material is encoded with. Again, it does this quite well, but it can look a bit dark on some monitors, so on your Sony, look for the Gamma setting and try lowering it – you’d usually expect a gamma of 2.2 for SDR but you may need to lower it to 2.0 or even 1.8. I’m assuming you’re watching UHD BluRay rips ,so the correct settings as far as I can see should be: Playback: Automatic Frame Rate: Switch Frame Rate & Resolution Display: HDMI Mode: 3840x2160p 23Hz HDR: SDR Rec.709 HDR to SDR: Vivid Advanced Settings: Deep Colour Mode: Off (8-bit) Colour Space Mode: YCbCr 444 HDMI Range Mode: 16:235 You definitely don’t want to choose SDR Rec.2020 since you projector doesn’t support BT.2020 so the image would lose a lot of colour as explained above as it tries to show a wide colour gamut signal in a narrower gamut. SDR2020 is for those who want to convert gamma from HDR to SDR but keep the wide colour gamut and have a projector that will allow BT.2020 with a standard power gamma. I think you need to get to the gamma controls of the PJ and fiddle with those. At the above settings the bandwidth required at 4K is only 8.9GHz, well into HDMI 1.4 territory, so any old HDMI cable should work.
Thanks Markswift, I'll try following your settings! I don't know if I can make things better with PJ gamma controls, since the image is clearly compromised at the source, but I'll also give it a try. Of course I'm not expecting a miracle from HDR to SDR conversion, but the gap between pre-converted SDR UHD BD rips and the HDR versions is like night and day; I'll post a couple of photos when I have the time.
Yeah, it'd be interesting to see what's happening, but I can tell you from experience that the HDR to SDR conversion is pretty good. As I said, not perfect, but pretty good. It's such a shame about that projector - it's such a good model, it just came out a year too early... a bit like my JVC - came out with HDR but before any decent HDR content so they took a stab at the EOTF and got it badly wrong. Fortunately there are ways around, but it took a lot of effort to get HDR right.
Yeah, I know what you mean Well, I think we're still in the middle of a big change, and we should see our machines as fantastic 1080p projectors (Sony's 4k matrix with Reality Creation and JVC's E-Shift4 really make a huge difference) with the added bonus of 4K. In my opinion, this is not a good time to buy a new projector. The key word here is Laser: both the JVC Z1 and the Sony VW760ES are laser projectors, and it's pretty clear we're goin' in that direction, since HDR is so light-hungry (in a couple of years, I'm sure we'll have incredible laser projectors on the 7000 USD/EUR range... and we'll never have to change another lamp). Goin' back to my problem, I'm sorry to say nothing changed with the settings you've suggested. Here's a quick comparison: keep in mind I took the pictures with a smartphone, and the HDR images look much brighter and contrasted than they really are (I guess the camera is compensating); I've set the Gamma to 1.8 in both cases 'cause it's the brightest, and the posterization and yellowish tint of the HDR become more visible that way. So, here's the Zidoo Z9S output of a pre-converted SDR rip. Pretty nice. And here's the Zidoo Z9S output of an HDR rip. Notice the severe posterization, and that horrible yellow tint (as I wrote, the real image is even darker and more washed out). Final comparison: I really don't know what to do anymore... The Sony VW500ES even has a Color Space setting with Rec.709, I've enabled that and it doesn't make any difference.
Your case is not good but seems a bit better than mine (see my samples). Can you test with a more colourful scene?
Ok, so I understand what you're seeing now... When the Z9S was first released, prior to firmware v1.9.7 the HDR to SDR settings were simple - either on or off. At this early point in the firmware development the conversion was very dark with standard gammas (2.2, 2.4) so in order to get the picture anywhere near where it should be you had to up the gamma in the projector to about 1.6. I even tried 1.4. I was able to do this in the JVC with a bit of maths and an imported custom curve, but even then it wasn't great. But there was no posterisation. With the introduction of v1.9.7 new gamma settings were added and along with this the posterisation seen in your images above. You'll see I posted about this at the time: http://forum.zidoo.tv/index.php?thr...-7-beta-version-for-zidoo-z9s-released.43240/ I also talked to support about it on numerous occasions but nothing was done about it. I'm not convinced that they understood what the problem was but by that time I'd given up on HDR to SDR and was using custom gamma curves in the projector with the Zidoo spitting out HDR. Later on I was involved with tweaking the new SDR.2020 settings which were introduced recently. This is something that really helps projector owners (unfortunately not yours because of the lack of BT.2020). So SDR.2020 does the HDR to SDR gamma conversion but leaves the colour space alone and does not exhibit any posterisation. So it seems the posterisation comes from a bad colour space conversion and not in the HDR to SDR conversion (it's not as simple as that since the both are intertwined, but it's a sort of top level way of looking at it). The problem you would have in using SDR.2020 is that your projector will map the BT.2020 colour values into Rec.709 space without scaling and so the images will never hit the correct saturation and will look grey and lifeless. So sad to say, your kind of stuck with it although I seem to remember one of the gamma settings "vivid" on the Zidoo really minimised the posterisation but I presume you've already tried this. It's definitely worth sending those images to service@zidoo.tv with an explanation - maybe an image in each gamma mode, bright, cinema and vivid.
Your pictures look like HDR is not kicking in on the projector - particularly the first one - assuming the top one is SDR and the bottom one is HDR, that would suggest that the HDR image is not being processed either in BT.2020 colour space or a PQ gamma curve - that's exactly what HDR looks like when pushed into Rec.709 at ST.2084. Also, looking at the second one, why is the SDR image at 4K and the HDR one at 2K and why are both at 60Hz (I'm assuming these are film source)?
That's very unfortunate, now I'm in a tight spot... I'll be sure to write at that address, but I don't have much hope. I'm still in time to send back the Z9S to Amazon, but the SDR content looks good - and yet, I'm afraid those SDR conversions will become quite rare in the future, since basically every TV has HDR now. Thanks a lot for your help Markswift, I really appreciate it!
You're very welcome and I hope you get a solution. I've also emailed them so will post any replies here. At the moment, I would say the only devices to provide excellent HDR to SDR conversion are as follows: 1. Panasonic BluRay players - Pros - excellent conversion, plays discs. Cons - no jukebox (video wall), no HD Audio on network playback (so no Atmos or DTS-X) 2. Oppo 203/5 - Pros - excellent conversion, plays discs. Cons - no jukebox, discontinued and damn expensive! 3. Oppo Clone M9702 - Pros - excellent conversion. Cons - no jukebox, not got great support, a bit expensive. 4. MadVR - Pros - superb conversion and flexibility. Cons - needs a well designed costly PC and a lot of time and patience to maintain - has to be a hobby. 5. Lumagen Radiance Pro processor - Pros - superb conversion, can be used with any source, excellent support. Cons - Cost! It's also worth noting here that you may want to try a Zidoo X9S if you can get one - this is the predecessor to the Z9S and has ALL the functionality of the Z9S with the exception of the new HDR gamma settings - I don't think the SDK allows it so I doubt that will change either. It is very marginally slower than the Z9S but you'd never notice and I have to admit it does a pretty decent job of HDR to SDR without the posterisation. I don't recognise that film you have screen shotted, but if you want to tell me what it is and what the time code is, I'll see if I've got it and send comparisons of HDR vs SDR on the X9S - I have one hooked up to a 75" Samsung TV here...
Thanks, that'd be very helpful! The movie is Alien ("no blood... no Dallas.", when Parker finds Dallas' flamethrower, around 1:29:00... it's right at the beginning of a chapter, so it'll be very easy to find) By the way, I'm seriously considering your X9S idea. I've never compared the systems, but it might be a very good "solution"! I don't need any of that poster wall stuff, so I don't think I'll be bothered by the difference in speed.
Ok, not as good pics as yours, but they serve their purpose- same scene, first in HDR, second in HDR to SDR - this is on a Samsung 75" 4K LCD so apologies for crap slightly overexposed iPhone images! Subjectively, there's not a great deal of difference between the two in reality. And of course, there's no posterisation. HDR: HDR > SDR HDR > SDR Closeup I think the results are much better than the Z9S - so much for progress!! (Guys, I hope you're seeing this ) Mark
Seems like the X9S is doin' a fine job! Of course most of the apparent posterization comes from the overexposed smartphone shots, in the closeup everything's much nicer. Color space on the Samsung is Rec.2020, I guess? Well, it all comes to the final question: if the X9S outputs a good, simple rec.709 color space that won't confuse my Sony VW500ES. I still have until November 20th to send back the Z9S to Amazon, so in the next few days I'll have time to try more settings, but I'll probably switch to the X9S. It's really a shame, this kind of problem could be easily fixed with a firmware update... but I don't have that kind of time. By the way, thanks a lot Markswift, without your kind help I'd never had thought about the X9S! All your posts have been incredibly helpful.
