yashsingh1/xdaforums huggingface dataset:
[Windows Phone 7 General] pat_pad:
worked partially for me

I have the Samsung Focus and the banding was a problem in some images especially with the HTC Hub that I side loaded. When the animation starts in HTC Hub the banding is clearly visible. I tried the registry entries given here (the keys were not present earlier), the banding disappeared in the HTC Hub but not in the image posted by WMPoweruser.com (Yes, I have downloaded the image and not viewing in the browser :)).

However, the interface lags in scrolling sometimes. It is kind of irritating. :(
[Windows Phone 7 General] Endeavour1934:
This one works perfectly on the HTC Trophy without losing any performance :D
[Windows Phone 7 General] vangrieg:
Sorry for probably stupid (and maybe off-topic) questions, but

a) what are default settings for these registry values if I want to revert things, 16 for each value or what?

b) how exactly do I go about changing these? I'm using "Registry Editor" on my Mozart, and it doesn't show these keys/values. I can only enter things manually. I'm okay with that, but what's the syntax? In "Path", should I start with HKLM or HKEY_LOCAL_MACHINE? In "Type", should I just type "dword"?

Maybe you all are using some better registry editor?
[Windows Phone 7 General] Depechie:
Any luck for the Trophy? These reg keys don't exist on it!
[Windows Phone 7 General] vangrieg:
They do, you just don't see them in some (all?) registry editors. Some keys are write-only.
[Windows Phone 7 General] tchimev:
They exist. But there is no difference if you change them.
[Windows Phone 7 General] bbakermai:
Hmm. Using WP7 Root Tools, which shows more reg entries than the original Samsung Focus Registry Editor, and I do not see these keys under HKLM/Drivers/Display/Primary. This is a post-NoDo Samsung Focus (AT&T). And yes, I need to edit my sig :).
[Windows Phone 7 General] bkaul:
Same here. But after adding them and setting to 32, there is definitely improved color depth. (For example, fire up the Messenger by Miyowa app and set the background to the default gradient that was so hideous before: it actually renders smoothly now.)
[Windows Phone 7 General] bkaul:
As for performance, I haven't noticed any problems yet, but it's only been a few minutes since I applied this. I set all three values to 32. Got 22 FPS in WP Bench before, 21 after.
[Windows Phone 7 General] sensboston:
Such a nice and very useful hack! +1, thanks!

P.S. Small tip: official XDA app is a very good banding tester ;)
[Windows Phone 7 General] bkaul:
Update: setting all three to 24 causes serious performance degradations; PanelBPP and BPP being 32 while PrimBPP is 24 seems to be the best mix here. Gradients are still nice and smooth with those settings.
[Windows Phone 7 General] nok_fusion:
thanks for u experience,can anyone else can tell us what value is the best?

i do not want perfomance crashes with this tips
[Windows Phone 7 General] Sebo1985:
Wow, i just created these values (all three to 32) and the banding is much much less visible.

Samsung Focus here.

No performance issues in the first minutes.
[Windows Phone 7 General] leo44:
Any solution for locked phone users ?

Maybe the Diagnosis Samsung app could be used for that ?
[Windows Phone 7 General] nardii:
I tried this out on a pre-nodo Omnia 7 with these settings:

HKLM\Drivers\Display\Primary\PrimBPP dword 24

HKLM\Drivers\Display\Primary\bpp dword 32

HKLM\Drivers\Display\Primary\PanelBPP dword 32

and now my screen is completely red and won't display anything else. So don't do that. Going to try to update now to see if it fixes it (otherwise I'm afraid I'll have to hard reset :(?)
[Windows Phone 7 General] spliffmonkey187:
I used this fix on my NoDo Omnia 7 (Orange UK: forced update via disconnect trick). My banding issue has all but disappeared it sems. Alot of my higher color depth images no longer band. I used these settings:-

HKLM\Drivers\Display\Primary\PrimBPP dword 32

HKLM\Drivers\Display\Primary\bpp dword 32

HKLM\Drivers\Display\Primary\PanelBPP dword 24

I input them into the registry using the WP7-RootTools.
[Windows Phone 7 General] nardii:
I just updated to 7008 (the February update) and it's working fine now. Gradients look better as well.

So, again, don't try this if you have not updated your device yet (at all)!
[Windows Phone 7 General] bkaul:
Pull your battery for a couple seconds and reboot. Did the same thing to me, but running like a dream after booting fresh.
[Windows Phone 7 General] bkaul:
So I guess the big question is, what do these registry settings mean, specifically?

BPP is presumably Bits Per Pixel; not sure on the prefixes though. Do we know what the effect of changing PanelBPP vs PrimBPP is in reality?

I have mine set as:

HKLM\Drivers\Display\Primary\PrimBPP dword 24
HKLM\Drivers\Display\Primary\bpp dword 32
HKLM\Drivers\Display\Primary\PanelBPP dword 32

while I've seen others suggest:

HKLM\Drivers\Display\Primary\PrimBPP dword 32
HKLM\Drivers\Display\Primary\bpp dword 32
HKLM\Drivers\Display\Primary\PanelBPP dword 24

Both settings seem to be working well, with no performance degradations, for many people. I think the consensus is that we want the root BPP (no prefix) to be 32. But is it Panel or Prim or both that it's best to degrade to 24? Degrading all 3 causes seriously laggy performance here.

I was speculating, purely from the names, that BPP might be the native OS bit depth, PanelBPP might be what the drivers for the display panel are set to use at the output, and PrimBPP might be a "primary" start screen, etc. setting, which is why I downgraded Prim rather than Panel. But I don't really know what the distinction between the three actually is, so couldn't say whether that's really the optimal choice based on underlying principles, only that it works well on my phone in practice.

I did have a red screen on shutdown after changing the settings, as nardii indicated he ran into on his Omnia. Pulling the battery and then booting back up fixed that problem. (And I've since rebooted again to swap to a fresh battery, with no further crashes on shutdown or other issues.)

Visually, on my Samsung Focus (AT&T), banding had been evident from the beginning (everyone had assumed it was something unique to Samsung's SAMOLED screens since it affected the Focus and Omnia but not HTC & LG devices) and was still present after NoDo; it seems HTC's firmware update caused some of their devices to join the crowd - NoDo has nothing to do with it, so far as I can gather. After these registry changes, gradients render smoothly with the increased color depth.

So far as I can tell, that's the current state of things. Is anyone able to shed some light on which registry setting effects precisely what?
[Windows Phone 7 General] Endeavour1934:
No idea, but on the Trophy (one of the slowest WP7 devices) if you use the first combination it lags a lot. With the second (PanelBPP 24) it works smoothly and without any banding at all.
[Windows Phone 7 General] tchimev:
Even with PanelBPP=24 I still have banding in pictures gallery.
[Windows Phone 7 General] Jin187:
A good test to check performance the performance difference is to play music in the background (using zune), then navigate around the home screen. I have found that All changes have performance issues so far.
[Windows Phone 7 General] Endeavour1934:
PanelBPP=24 and the other two set to 32, of course. Changing only one of the three values does nothing.

I don't even need to zoom into the pictures, there is no banding after loading them. :D

Using

HKLM\Drivers\Display\Primary\PrimBPP dword 32

HKLM\Drivers\Display\Primary\bpp dword 32

HKLM\Drivers\Display\Primary\PanelBPP dword 24

and navigating around the OS, scrolling etc. with music on the background = 0 lag and no sound distortion (on HTC Trophy with FW 12000)
[Windows Phone 7 General] Depechie:
Thx Endeavour1934, those settings helped my Trophy too!!

And I must agree with others on this, it was NOT visible after the Nodo, but the problem occured only after the HTC update ( what arrived few days after the Nodo )
[Windows Phone 7 General] ryotgz:
Great find.
[Windows Phone 7 General] rdsjuggalo:
works very well on my focus also..:D
[Windows Phone 7 General] ScottSUmmers:
Oh man, thanks for this combo. I'll have to play with it some more my HTC Arrive, but this combo definitely fixed it. Now I just have to fix the lag on the home screen.

ETA: On second glance and after spending a bit of time, looks like it was a bit of a placebo effect combined with the ever so slight difference in speed.
[Windows Phone 7 General] ScottSUmmers:
On a related note, would anyone please tell me if the performance with this registry edit is the same as it was pre-NoDo?
[Windows Phone 7 General] Serjio_Z:
HTC Mozart. Not working.
[Windows Phone 7 General] tchimev:
Of course I changed the three values but still have banding in gallery.

If I use a picture as Wallpaper the banding issue is gone.

HTC Trophy.
[Windows Phone 7 General] hinds:
How did you edit the registry? I don't see those keys so I manually added them but still can't see the entries and I observe no change.
[Windows Phone 7 General] kendallj:
HTC Mozart: against the flow, changing values to either 32 or 24

causes

an obvious deterioration resulting in significant banding. Setting all values to 16 definitely gives the smoothest transitions. Why???
[Windows Phone 7 General] Kana-chan:
Hello,

I have made some tests changing the values from 16 to 32 or 24 but there is no difference into the pictures, even if I zoom on them.

I have a HTC 7 Mozart.
[Windows Phone 7 General] Necroman_AI:
Are you guys sure this is caused by NoDo and not HTC updates or HTC bootloader versions?
[Windows Phone 7 General] tchimev:
The banding issue start showing after i installed the htc update.

Its not after the nodo update.
[Windows Phone 7 General] seraphin54:
On my HTC mozart , Banding is still here even after tring all combinations.

:(
[Windows Phone 7 General] stan2:
Hello all,

So I tried this back and it works like a charm. I do notice some performance issue, but no biggie. One problem is flickering screen on white-filled screen (rarely happen though). I also notice this is a constantly problem for the LG Optimus 7. This reg hack does not apply to IE. IE still work in 16bit.

Now I have one question, how do I revert to original value? Just change all the dword back to 16?
[Windows Phone 7 General] amtrakcn:
Just revert to the original value. For me, my Focus does not have PrimBPP key originally, so I changed it to 0.
[Windows Phone 7 General] stan2:
I changed mine to 16 and it seem to be back to 16bit now. I think those keys are there, it's just hidden because of restricted access.
[Windows Phone 7 General] tslany:
What to try just delete these 3 keys? For me it looks like working
[Windows Phone 7 General] weijoon:
7 Mozart,

Asia ROM, Bootloader Version 1.28.2250.3 (stock)

Even in stock build (7004), banding already exist,

updated to Feb & March update,

Banding still there,

Reg fix make it less visible, but confirm still exist.
[Windows Phone 7 General] bkaul:
FWIW, I checked the registry on my old WM6.5 device (an HP iPAQ 614 w/ custom ROM) that I haven't got rid of yet, and it has the bpp value (set to 16), but not the Prim/Panel ones, so no insight on what they do from that front, other than that they're apparently new to WP7.
[Windows Phone 7 General] mmuntean2:
Panelbpp is 24 an the rest are 32. you got them wrong.
[Windows Phone 7 General] bkaul:
That's about as useful as Steve Jobs' comment "you're holding it wrong."

I've seen both sets of settings suggested in this thread. On my Focus, I set panel to 32 and prim to 24 and it performs better than with all at 32 (which was barely worse than the default) or all 24 (which was terribly laggy). Other people (with other devices) have lag issues if they do this, but not if they swap panel & prim. What I think would be useful is somehow determining precisely what the PanelBPP and PrimBPP settings do, so we understand the distinction. "You got them wrong" is not terribly helpful in trying to compare and distinguish between the effects of the two settings.
[Windows Phone 7 General] Omega Ra:
Did these on my NoDo AT&T Focus and the banding is much better (used XDA app as test.
[Windows Phone 7 General] tiny17:
Applied the third value change to no effect on an HTC Arrive.
[Windows Phone 7 General] Mr_Waffle:
Registry tweak did the job for me :) It's still slightly noticible on some pictures, but overall a great improvement.
[Windows Phone 7 General] byobge:
I've had the "Hungarian" NoDo on a dev-unlocked Samsung Focus since last week - I definitely saw the banding in WPBench, applied the suggested changes, and the banding went away - awesome.

Today, the "real" NoDo became available, so I re-branded my Focus back to AT&T and installed it.

The install went fine, except that after the final reboot, I got the "Bright Red Screen" that others have alluded to. Pulled the battery, waited for a magical-thinking amount of time, restarted, and all was fine.

The odd thing is that, post-"real"-NoDo, PrimBpp, PanelBpp, and Bpp are all 24 - and yet, WPBench shows no banding. All the Color tests pass.

I have no explanation for this, beyond "huh."
[Windows Phone 7 General] byobge:
Spoke too soon on that "all was fine" above.

I still get the Bright Red Screen reliably after turning the phone completely off and back on. Pulling the battery always fixes it, but still, that's not cool. (Although now that Marketplace doesn't crash, I'll likely be turning the phone off less?)
[Windows Phone 7 General] bbakermai:
I got the bright red screen after the update was completed. I just restarted the phone and have not seen it since. I also checked my banding registry settings and they were not changed from 32,32,24. I #walshied my update and so, was never unbranded. Funny. Now I have a NoDo backup before NoDo :). Actually, I think the only update I got today was the Samsung firmware and Camera update.

Yes, he said to the observant, I will change my sig...just not now.
[Windows Phone 7 General] byobge:
bbakermai, just to be clear - if you power off the phone completely, do you get the Red Screen on startup, or was it just that first time after the update?

(Also, I just checked WP Bench on a friend's Samsung Focus which hasn't been updated ever - it definitely has the banding issue. It had been my impression that the lower bit depth had been introduced in NoDo, but that doesn't seem to be the case, at least on the Focus. Though this might be old news, already covered in the 11 pages of this thread.)

Thanks,

bob
[Windows Phone 7 General] byobge:
OK, never mind...

(1) after a little basic research, I learned that "banding" has been an issue on the Focus since launch - nothing to do with NoDo; and

(2) after deleting and re-creating the PrimBPP, PanelBPP, and bpp registry values, I've stopped getting the Red Screen after a complete shutdown. Feels like voodoo to me, but I'm not opposed to superstitions that work :-)

So now I have full color depth, "real" NoDo, and no Red Screen - life is, if not good, at least better.

bob
[Windows Phone 7 General] bkaul:
I've seen the red screen about 10% of the time on reboot since making the registry changes on my Focus, and it's happened no matter which of the two P___BPP settings is 24 with all else being 32. Pulling the battery always works. I haven't found a consistent predictor of when it will/won't red-screen on boot after shutting down, but 9 times out of 10 it doesn't have a problem here.
[Windows Phone 7 General] circleofomega:
I too have the banding issue..HD7...if only we could have ONLY the NODO and not the HTC firmware update...???

Is there a way to do it...??
[Windows Phone 7 General] bkaul:
More testing:

I deleted all three values to get back to the original state (16-bit), and the banding was (obviously) back.

I added in just the bpp=32 value, without the P____BPP values, and banding remained in the WP7 Bench gradient display test. I then added in PanelBPP=24, but did not add PrimBPP, and the banding remained. I deleted the PanelBPP value and added PrimBPP=24, and the banding was cured. So, PrimBPP has an effect on the display quality in apps while PanelBPP does not. I'm not sure yet what either prefix means, and I've yet to discover what (if anything) the PanelBPP value actually affects on the Focus.

Presently I've got bpp=32, PanelBPP=24, and PrimBPP=24, and haven't encountered a red screen, or any lag, or any banding. Still not sure what all the values actually do though.
[Windows Phone 7 General] ScottSUmmers:
those values work on my arrive too along with bpp=32; panelbpp=24 and primbpp=32
[Windows Phone 7 General] bbakermai:
bob,

Funny. I just rebooted based on your question, and got my first red screen since updating. I had rebooted several times in between without incident. Very strange. I did not delete and recreate the three registry settings. They were there before and after the update. When I got the red screen, I just rebooted, and it came right up. Rebooted again, and got a red screeen. Did the battery removal, count to 30, reinsert and got a good boot. oiy.
[Windows Phone 7 General] byobge:
bbakermai,

I think the delete/re-create was a red (ha ha) herring - what I'm really seeing is what bkaul, slightly upthread, is seeing - *any* registry changes I make might (not always, but pretty often for me) cause a Red Screen.

Strange and irritating, but pulling the battery always fixes it, so it doesn't bother me a LOT. (What does bother me is that taking the back off the Focus makes me feel like I'm breaking something... I don't know how many snap-off/snap-on cycles this chassis is spec'd for :-))
[Windows Phone 7 General] bkaul:
Hmm ... What I meant was that since making these registry changes (bpp=32, PanelBPP=32, PrimBPP=24), about 10% of the time I reboot I got a red screen. Usually when I reboot w/o swapping batteries it's either to toggle between tethering/zune sync mode or because I was experiencing the 10-SMS-received problem (I think that's resolved now), not due to making other reg changes. 9 times out of 10, it did fine, but occasionally, it'd red-screen.

I haven't had a red screen since setting both P____BPP values to 24 with bpp at 32, but I've also only rebooted a couple of times, so who knows ...

I'm not saying your hypothesis of any registry changes being a possible trigger is incorrect, only that I hadn't made such a connection myself. I haven't tracked when I change the registry closely enough to know whether some of those intermittent red-screens I got were due to changes there.

As for snapping the back cover on/off the Focus, I've gotten used to that - I carry a spare battery with me and swap out on heavy-usage days if necessary.
[Windows Phone 7 General] Anthonok:
my focus is now beautiful as well. i used 32 32 24
[Windows Phone 7 General] arm_jstp:
It works

The setting works great to my official NoDo Samsung Focus! I didn't ware of the banding before update. After installation, the banding looked terrible. Thanks a lot!
[Windows Phone 7 General] nok_fusion:
someone can post in 1st page the value to put in devices HTC/Samsung/Lg/Dell who run smoothly,i want to change the 16 bit of my mozart but most of people got different results
[Windows Phone 7 General] thenewperson:
Pardon my noobness, but how do you change these keys?
[Windows Phone 7 General] ScottSUmmers:
chevron or developer unlock your phone first, then edit with the appropriate registry editor depending on the manufacturer of your phone.
[Windows Phone 7 General] kainy:
I have Samsung Omnia 7 I didn't have the keys so i made them. I'm using:

PrimBPP dword 32

bpp dword 32

PanelBPP dword 24

And everything is just perfect!!!!!!!! :) Thanks all!
[Windows Phone 7 General] circleofomega:
Sigh...WHy is it only for the unlocked devices...isn't there a trick for the locked ones?
[Windows Phone 7 General] ScottSUmmers:
That's just the design of the platform. Ideally developers should be the only other group of people outside of MS that should have access to make system changes. Of course that's not the case with the people that were able to get in with the Chevron unlocker.

Other than that, according to the design of the platform there really isn't much reason for the consumer to access the registry.

With that said, sorry no trick for the locked ones other than to hit up MS or your carrier to hit up MS.
[Windows Phone 7 General] thenewperson:
Thank you so much everyone. This fixed an issue that was bothering me so much.
[Windows Phone 7 General] Omega Ra:
I was getting the Red screen on reboot a lot. But my screen cracked and now I have a new phone. Trying to decide if I should put them back in or not. The banding is back (obviously) but the red screen on reboot causing me to have to reboot again was a little annoying...
[Windows Phone 7 General] nok_fusion:
i install the tool of julien schapman "config advanced 1.2.0 xap" & I check to active 32 bits mode on my mozart,just reboot & all working fine until now (i do it yesterday) no lagging,no speed decrease,so try it
[Windows Phone 7 General] munkeyphyst:
my banding experience

I have an att-us focus, running nodo with the samsung update. I am unlocked.

I have significant banding with the XDA App splash screen and have been reading up here on how to solve my banding problem. I downloaded the landscape picture from here: http://wmpoweruser.com/has-the-htc-update-caused-some-windows-phones-to-go-16-bit/

When viewed through IE, obvious banding

in thumbnail view in the photo hub, banding is obvious

once zoomed in even a little bit, no banding whatsoever

used it as wallpaper, obvious banding.

I haven't made any of the proposed registry changes as yet.

I believe I will set the following when i get home.

HKLM\Drivers\Display\Primary\PrimBPP dword 32

HKLM\Drivers\Display\Primary\bpp dword 32

HKLM\Drivers\Display\Primary\PanelBPP dword 24
[Windows Phone 7 General] munkeyphyst:
Ok. Did the registry changes.read settings before writing and they were set to 0. After restart:

Banding still shows in IE (I know that's expected)

Thumbnail still shows banding in photo hub

Zoom in and banding is gone

Set as wallpaper, banding gone

Xda app splash screen banding gone

No perceived performance downgrade thus far

I like :)
[Windows Phone 7 General] Strike_Eagle:
Nothing. No issue on my T9292 HD7 T-Mobile

I have flashed my HD7 back to 7004 for 2 days, and then re-updated through Zune both pre and Nodo)

Firmware version: 2250.09.12001.531

Version WP7 7390 (no-do)
[Windows Phone 7 General] Omega Ra:
tried, app doesn't work on my focus.
[Windows Phone 7 General] munkeyphyst:
I used the Samsung registry xap on my focus
[Windows Phone 7 General] Omega Ra:
Oh, I can do it, I have the WP7 root tools so I can get it in there no problem, just deciding if I want to again. With the previous phone I Was getting the red screen on just about every reboot, and don't know if I feel like doing that again
[Windows Phone 7 General] circleofomega:
Thanx but there is just one small error with what you said, its NOT MS this time, its HTC who have screwed up this time...its the HTC firmware update that has gone awry and brought us this Oh SO NOT needed banding issue...

Otherwise I quite buy your point...
[Windows Phone 7 General] bioan:
I cannot find those three registry entries on my Omnia 7.

HKLM\Drivers\Display\Primary\PrimBPP dword 24

HKLM\Drivers\Display\Primary\bpp dword 32

HKLM\Drivers\Display\Primary\PanelBPP dword 32

Any ideas ? I'm on Pre-NoDo
[Windows Phone 7 General] munkeyphyst:
Write them anyway
[Windows Phone 7 General] bioan:
Thank you ! They did the trick !
[Windows Phone 7 General] vel0city1:
I didn't have this issue before, but since my Surround got the updates the other day I've had the banding problems. Has Microsoft announced this as a known issue that they are working on? It sucks that the only way to fix this is to unlock and mess around with the registry.
[Windows Phone 7 General] munkeyphyst:
Cool. :)
[Windows Phone 7 General] ScottSUmmers:
Really now? From what I've been reading in the thread the problem was on some people's Samsung Focuses and Omnia 7's
[Windows Phone 7 General] giciorek:
This hack doesn't work on HTC Mozart with 7.0.7392.0