Color Ghosting with OBS

[ArctiCMooN]

Hi there,

I am recording with a VisionSC-UHD2 card, but basically the problem exists with all my capture cards. When I try to record from that card with lossless settings, I get color ghosting in my video files. The color ghosting only appears while recording in 3840x2160, and not in FullHD recordings.

I use standard settings for OBS which means: simple mode, lossless quality, 3840x2160. From what I know OBS uses UT.video as codec for lossless recording.

The captured sources are video game consoles connected via HDMI.

The ghosting looks like this, look at the doctors head.


[Attachment 48137 - Click to enlarge]

Can anyone help me, this is driving me mad. Thanks in advance, I appreciate every tip.

[jagabo]

Are you capturing an interlaced source?

[ArctiCMooN]

No, it's standard consoles like PS4 Pro and Xbox One X. Their signal output is set to 2160p RGB. When I capture with an Elgato Device using their proprietary software it works. But the software only outputs h.264 which I can not use.

When I capture with my BMD Decklink 4K Extreme 12g, there also is no color ghosting, when I use Media Express (the software from Black Magic Design).

I played with some settings in OBS, I actually can set OBS to record in RGB (NV12 is standard), then there is NO ghosting but tearing.

[jagabo]

Still sounds like an interlaced vs. progressive chroma problem. Do yo have YV12 as an option? Can you upload a short sample (that clearly shows the problem) for analysis?

[dellsam34]

If BM software and card works why don't you just stick to them? It can do lossless. Did you try capturing YUV instead of RGB with other cards?

[KarMa]

Looks like some kind of improper YUV decoding or encoding, like something is getting NV12, YV12, i420, or YUY2 mixed up. As NV12, YV12, and i420 should all output the same exact video but the actual information is stored in different order between them.

[jagabo]

Looking closer, it doesn't look like the usual interlaced/progressive chroma problem. The errors appear to be limited to the U channel:


[Attachment 48140 - Click to enlarge]

You can see the ghosting in the U channel but there doesn't appear to be any in the V channel.

[amaipaipai]

To me looks like you system can't handle lossless, try MJPEG or something else.

[KarMa]

To me looks like you system can't handle lossless, try MJPEG or something else.

An under powered system doesn't cause this ghosting.

[amaipaipai]

An under powered system doesn't cause this ghosting.

This is caused by a ProRes codec my system can't process.


Good luck, hope you find a solution for him.

[ArctiCMooN]

Still sounds like an interlaced vs. progressive chroma problem. Do yo have YV12 as an option? Can you upload a short sample (that clearly shows the problem) for analysis?

I have uploaded it to WeTransfer. The file is quite huge for being only 4 Seconds longs: https://we.tl/t-7vsQ1uJVdX (I hope this doesn't break any forum rules).

To me looks like you system can't handle lossless, try MJPEG or something else.

My system is a AMD Ryzen Threadripper 1950X (16 cores @3.4 GHz, 32 threads), 64 GB DDR4 3200 RAM, 1TB Samsung Evo 970 PRO PCIe M2 (which is one of the fastest SSD cards). It should be prepared for lossless capturing I think.

...Do yo have YV12 as an option?...

[Attachment 48143 - Click to enlarge]

[Attachment 48144 - Click to enlarge]

[Attachment 48145 - Click to enlarge]

If BM software and card works why don't you just stick to them? It can do lossless. Did you try capturing YUV instead of RGB with other cards?

The BMD DeckLink 4K Extreme 12G doesn't work well with the Xbox One X. That's why I switched to the VisionSC card.

Do you think the problem is OBS? Might there be another good recording software?

Thanks for all your input so far!

[amaipaipai]

My system is a AMD Ryzen Threadripper 1950X (16 cores @3.4 GHz, 32 threads), 64 GB DDR4 3200 RAM, 1TB Samsung Evo 970 PRO PCIe M2 (which is one of the fastest SSD cards). It should be prepared for lossless capturing I think.

This doesn't mean anything if the software you are using can't handle a RAW 4k capture. Virtualdub can't handle a 1080p capture with my BM card.

I also use Blackmagic cards and the ghosting you are seeing is a signature that something in there can't handle the capture, something there is off, in my case any Apple ProRes cause ghosts in the captures.

Blackmagic has a software to handle capture, use it.

By the way, you know what you are doing?
Have you tested this settings before?

My MB card doesn't work with RAW capture and I'm sure any BM card will work either, you have to choose any "uncompress" formats BM provides, otherwise you'll have problems.

[ArctiCMooN]

My system is a AMD Ryzen Threadripper 1950X (16 cores @3.4 GHz, 32 threads), 64 GB DDR4 3200 RAM, 1TB Samsung Evo 970 PRO PCIe M2 (which is one of the fastest SSD cards). It should be prepared for lossless capturing I think.

This doesn't mean anything if the software you are using can't handle a RAW 4k capture. Virtualdub can't handle a 1080p capture with my BM card.

I also use Blackmagic cards and the ghosting you are seeing is a signature that something in there can't handle the capture, something there is off, in my case any Apple ProRes cause ghosts in the captures.

Blackmagic has a software to handle capture, use it.

By the way, you know what you are doing?
Have you tested this settings before?

My MB card doesn't work with RAW capture and I'm sure any BM card will work either, you have to choose any "uncompress" formats BM provides, otherwise you'll have problems.

This is not about my BM Card. It works fine with MediaExpress as I stated before. This is about chroma shadows / ghosting / blending in OBS.

[amaipaipai]

This is not about my BM Card. It works fine with MediaExpress as I stated before. This is about chroma shadows / ghosting / blending in OBS.

Of course not, my card also works fine with ME and if you noticed in the ME setup, you can't capture in RAW format as OBS do, you need to choose any of the uncompressed codecs.

If you are having problems with OBS there is nothing we can do here, go to the OBS website and ask for support there, they are the only people that can solve your issue.

[poisondeathray]

Chroma delay in your recording. Cb,Cr are temporally and spatially aligned, but not with Y'

Not sure of underlying cause, but you can offset either the chroma, or luma to match . But test on longer sample , because a variable delay would pose problems . You should debug the underlying cause

eg.

a=ffvideoSource("2019-02-19 17-57-10 (2).avi")
u_chroma = UToY(a)
v_chroma = VToY(a)
YToUV(u_chroma, v_chroma)
mergeluma(a.trim(2,0))

[jagabo]

I agree with poisondeathray. The luma is lagging two frames behind the chroma. A simpler fix:

WhateverSource()
MergeChroma(last.Trim(2,0), last)

Also, every pair of frames in the sample are the same. You might as well have captured as 30p. Maybe the source is really 60p at other times?

[ArctiCMooN]

Also, every pair of frames in the sample are the same. You might as well have captured as 30p. Maybe the source is really 60p at other times?

Thanks for your inputs. The source output is 60 fps, the video game itself only 30 fps, that's why every second frame is a duplicate. And that's why I do all this: I have a software, that searches an uncompressed video file for duplicate frames. Sometimes, there are more duplicate frames in a row so the game has frame drops which can be a hint for performance issues. So I basically try to visualize the frame rate of a console video game by analyzing uncompressed or lossless video footage.

Other than that, my knowledge about this topic (especially color spaces, channels etc.) is very very limited

Where do I need to enter the code?

[JVRaines]

Have you tried updating the OBS software? As I recall, it uses FFmpeg under the hood. Perhaps there is a programming error in the FFmpeg library or in the way OBS is calling it.

[jagabo]

Other than that, my knowledge about this topic (especially color spaces, channels etc.) is very very limited

YUV video is a rotation of the RGB cube so that the greyscale values fall along one axis (Y) and the U and V axis represent colors added and/or subtracted from that greyscale image. (The origin of this is in the transition from B/W television to color television. Engineers wanted to keep a greyscale signal for existing B/W TVs and encode colors separately on side channels for color TVs.) For some reason in your cap the greyscale channel consistently comes from one frame and the color channels from two frames later. The given scripts simply re-sequence the channels so that they all come from the same frame.

Where do I need to enter the code?

Those are AviSynth scripts. You'll need to install AviSynth and an editor/encoder that supports AviSynth scripts as input (VirtualDub, for example). My "WhateverSource()" was symbolic -- use whatever source filter works for your source, AviSource("filename.avi") for example.

Of course, a better fix would be to find the cause and stop it from happening there. The fact that the colors lag by two frames, and every pair of frames is identical, suggests to me that the problem is happening in the capture device. Have you tried capturing at 30p? Does that show the same problem?

[amaipaipai]

The cause is that Blackmagic Cards doesn't work well outside BM software and other software are incompatible with BM codecs, simple as that. The OP won't even be able to do a simple 480i capture with Virtualdub using any BM card.
Outside this environment you'll get ghosting, audio delay, video interruptions and other side effects.

If the OP wants to capture game footage get something else instead, BM cards are not build for this and there tons of people complaining about game capture at the BM forums, Google it:

game capture site:http://forum.blackmagicdesign.com/

https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=11268

There's nothing we can do here unless the OP are willing to avisynth process EVERY capture he does to fix this BM mess.

[ArctiCMooN]

Thanks to all of you to make me understand the problem, especially @jagabo for the detailed explanation.

@amaipaipai This problem is not only caused with my BM card, it is all cards (I have a Magewell Pro Capture HDMI 4K Plus, the BM Card and a new VisionSC-UHD2). No matter which card I use, the color ghosting appears in OBS, only with 2160p60 and only with lossless settings that uses the UTvideo codec.

I will try to work myself into AviSynth and VirtualDub.

[KarMa]

What exactly do you have your card outputing, as it appears to have many different output options. Which UT Codec are you picking from, as there a many. You could try other lossless options with FFMPEG which is included in OBS. Like Lagarith or Huffyuv.

[ArctiCMooN]

What exactly do you have your card outputing, as it appears to have many different output options. Which UT Codec are you picking from, as there a many. You could try other lossless options with FFMPEG which is included in OBS. Like Lagarith or Huffyuv.

I tried other options, but huffyuv for example causes a very unstable image with tearing or even worse:


[Attachment 48205 - Click to enlarge]


[Attachment 48206 - Click to enlarge]

My config is normally like this:


[Attachment 48207 - Click to enlarge]


[Attachment 48208 - Click to enlarge]


[Attachment 48209 - Click to enlarge]


[Attachment 48210 - Click to enlarge]

[jagabo]

Did you try changing the color format from NV12 to YV12, YUY2, or some other YUV format?

[ArctiCMooN]

Did you try changing the color format from NV12 to YV12, YUY2, or some other YUV format?

Yes, the result stays the same. I get the same tearing and so on with every color format, some color formats deliver wrong colors in addition. I thought this was easy just plug and play (install the card, install the driver and go), but except from h264 nothing really works. For my normal comparison videos I use an Elgato card, it works well enough without any problems, but i cant do frame rate tests with h264 files, the compression ruins everything. Sorry to be so annoying...

[KarMa]

In post #23, on the 5th picture there is a drop down menu called "Capture". It's in auto mode, what other options are there? As the output from something like a Playstation or a Xbox over HDMI is going to be RGB, not YUV. So capturing in YUV might be a problem.