December 9, 2019 at 08:39 #24717
Recently I notice an issue on color shift & pixelation. It only becomes very noticeable when the screen on server side has bright colors e.g. visiting Reddit. Anything with bright red on a dark background is a good test like the one below. Screenshots to demonstrate the issue I saw:
- NX with H264 at max quality: nx_h264_max.png
- Apple Screen Sharing at max quality: apple_vnc_max.png
- The test image (a screenshot of the live website): “Screenshot 2019-12-09 at 12.58.23 PM.png”
- URL of the live webpage tested
Note the pixelation of small features in red such as words and the dullness in bright colors.
Server is Catalina 10.15.1 (I saw the same on Mojave before upgrade). It runs AMD GPU with Metal support at 2560×1440 resolution. H264 software encoder. NX display quality at maximum. I’ve also tried VP8 and MJPEG encoding. See the same problem.
Client is Mojave. Also played with different combinations available on NX display settings to no avail.
Cheers & thanks
Attachments:December 9, 2019 at 17:24 #24739December 12, 2019 at 12:23 #24846
Thanks for the logs. Please check if any of the these helps:
1) turn off UDP (Edit connection -> Advanced -> uncheck ‘Use UDP communication for multimedia data’);
2) uncomment and set the EncoderMode key (in /Applications/NoMachine.app/Contents/Frameworks/etc/node.cfg) to the following:
(then restart the server)December 13, 2019 at 08:58 #24851
Thanks for the prompt help. I tried your suggestion but no difference unfortunately. Based on in-line comments in the file, I also tried ‘EncoderMode quality’ but no difference either.
CheersDecember 19, 2019 at 18:09 #24930
I wasn’t able to reproduce your problem. Could you send a screenshot of the scaling options from the display settings of both your client and server Macs?January 2, 2020 at 09:20 #25070
Server side has four items listed under “Scaled” resolutions:
Client side has exactly the same items.
I tried to set server to different scaled resolutions in macOS. I also realized that NX client can request custom resolution as well as setting to match client. Played with them individually or in combination. Make no difference.
I believe the issue may be before the encoder (as it happens in h264, VP8 and MJPEG). Perhaps a common setting applicable to all of them in the encoding pipeline.
I’m no expert in video encoding. Google pointed me to discussions about color space. In particular, some people mentioned YUV 4:4:4 vs YUV 4:2:2. The latter hurts bright colors in non-video materials (such as graphics and text). Don’t know if it’s relevant but worth checking.
CheersJanuary 14, 2020 at 15:59 #25230
You must be logged in to reply to this topic.