why does dark scenes in videos look bad?

[aleks170880]

I have not used netflix, or other video streaming sites, until today - but when I watch the movies, and there are dark scenes - the video looks bad when there is movement in the screen.

Are there any way to fix this?

 

[Keith White Jr]

I have not used netflix, or other video streaming sites, until today - but when I watch the movies, and there are dark scenes - the video looks bad when there is movement in the screen.

Are there any way to fix this?

What phone are you using?

 

[aleks170880]

Sry, forgot to mention it. Its on the Lumia 950. Everything looks great on that fantastic screen - but dark scenes in Movies look weird.
The black is really black, but dark Brown and dark Objects, does not look great -

 

[aleks170880]

Am I the only one with this trouble? Movies are unwatchable at this moment. Grabbed some screens - will post them tomorrow.

 

[ashram]

post them when you get a chance. sounds like compression artifacts, which could be in play depending on the resolution netflix is using for windows phone. it could also be the movie. i have seem some AWFULLY bad compressed movies on netflix, but they matched the crap quality on their DVD or Blue-ray.

 

[cristixxxlog]

i seem to have the same problem. Happening while streaming (youtube in edge, mytube) and also downloaded samples in various resolutions and frame rates. It is happening also on a FullHD 60fps video. This doesn't happen on any other screen: my laptop, my asus tablet (win10) or my wife's Sony Xperia Z3Compact. It looks like some banding issues...




This happens only on the Lumia 950 screen.
For comparison, it was playing the Star Wars trailer on youtube inside Edge. The link to the clip: https://m.youtube.com/watch?v=sGbxmsDFVnE

Can anyone test and see if the dark scenes - especially the transition scenes, from one scene -> make the screen progressive dark, then go to next scene and from dark go progressive to the scene.... Hope I made myself understood...

Also, there is something weird happening if, from lockscreen, I rapidly turn off/on screen. See the video below. This happens ONLY with glance activated (set on 30 sec). If I completely turn off glance this does not happen. Link: https://youtu.be/nmrqmARMJoo

Can someone make some test for both problems and tell us if they have the same problems? I'm on .39 version of OS.

 

[ashram]

pics you posted seem more like poor video compression. I wonder if it's the decoder or the video itself. only way to find out is to DL a high quality video on a PC and copy it over to the phone and play it back. if it looks fine, then it's the video stream being fed to the phone. if it looks bad, then it's the video decoder being used, nothing can really be done with that.

on my end, i haven't noticed video artifacts that bad on my 950.

the video you posted is something I get too sometimes. reminds me of an old windows video driver crash, but since it comes back up so quickly, i wasn't bothered by it.

 

[920Walker]

I have not used netflix, or other video streaming sites, until today...

This is quite common when streaming with any device large or small. Stream the same movie again and artifacts may appear in different scenes during round two. Bandwidth traffic and buffering will cause changes, even with what one perceives as a fast connection.

 

[cristixxxlog]

these happen on videos downloaded in high quality, hd, full hd (24 and 60 fps). videos that look good on any other screens. also that video streamed in chrome on android (Sony Z3Compact) on the same network looks good.
Please bear in mind that those screens are photographed, otherwise they look good on other screens. Also, look at the video in a darker/dimmer room. in day conditions it is almost impossible to spot these "stains/artifacts/bending"....

 

[uselessrobot]

The blockiness is due to compression. AMOLED displays tend to have a wider color gamut, so you see some artifacts that wouldn't be as apparent with LCD displays. However, I have noticed that AMOLED also tends to drop off below a certain threshold. So instead of a smooth transition to black, you get an obvious jump.

 

[cristixxxlog]

I understand this and the fact that it is somewhat normal for an Amoled to have this "Mura effect" in some degrees.
However, I tend to believe on my display is too pronounced. I'll try and play with some other 950's and see if/to what degree they have this problem.

Some other users say they have the problem, other don't.

Anyone elese experienced these problens on their 950/XL?

Sent from mTalk

 

[uselessrobot]

The mura effect is something very different than what is being described here. That's cloudiness due to manufacturing processes and can affect both LCD and AMOLED. That doesn't cause the odd contrast or blockiness seen in those screenshots. Those issues are related to compression algorithms and the nature of AMOLED.

As for the background flashing when unlocking the phone, I experience similar things. That is almost definitely software related. I'd say it's sloppy code. Along those lines, I've noticed recently that in settings, when the open animation plays the grey background flickers faintly. Again, poor code.

 

[mariusmuntean]

why on earth aren't you using a youtube app?? there are plenty in the store which are more than great: mytube, tubecast,metrotube etc

 

[cristixxxlog]

what is the relevance of your post?

how does that help us?

before these type of posts please read the previous posts.

I clearly mentioned "mytube" and "high quality videos downloaded in Hd, fullHD (24 and 60fps), 2k/4k.

to answer your question though, we use edge because we need a standard test to see if we have the same results. a youtube app has different user settings, not to mention having different youtube apps that could output different results...

now... going in edge, at that precise video, in a poorly lit room/dark environment, do you experience the same things? The most obvius are stains/spots on dark brown/grey gradients....

 

[mariusmuntean]

Notice it aswell on edge youtube and mytube. Weird though, looks like more of a color rendering problem which is clear a driver issue.

 

[cristixxxlog]

I checked a Vodafone unit inside a mall the past days and also another Orange one inside another shop.
Didn't see the "spots" in dark scenes on any phone (mine included) inside those shops probably because of too much light around.

The screen bug on quick on/off though was there on those phones.

I suspect that video is not rendered on GPU, but on CPU. Did some testing on browsers though, to see how and if edge drains more power than some others and it seemed to me that on video playback the GPU wasn't used. Or at least haven't seen a difference in usage.
Testing was on a laptop inside the browser with the device portal.
I'll re-download some high quality samples, including 4K and see what it is used to render them, gpu or cpu...

PS: Edge uses between 40-65% of cpu with 1-4 tabs opened.

 

[cristixxxlog]

Just to update on this.
Went to another Vodafone store the past days and found both 950 and 950XL on display and working. Also the shop was very bad lit, so the perfect scenario for testing this bug.
The 950 on display and my 950 suffers the same things. Black spots in dark scenes in videos, no matter the sorce.
Funny thing is the same video, in the same Edge, on the XL runs flawlessly. No problems at all, no pixelations, spots or anything.

Upon heavy digging the problem seems to be related to screen calibration, specifically the gamma curve. Simply the gamma level is set too high, making the different shades of dark grey be rendered either lighter than it should or simply black. I managed to replicate this behavior on the laptop, setting the gamma level some steps highe than normalr. The same pixelation/spots appear both videos and photos.
I also ran onto some veeeeery long topics on xda about the Note 1 that suffered the same things, albeit much worse.
Later today I'll come up with a solid testing to see if everybody has the same problems. Also I'll post samples from a different phone.

To me this is clearly a problem of screen calibration. What I do not know is if this is hardware or software. Since the AMOLED screen comes factory calibrated, and based on that we have further software calibrations in the OS and possibly apps....