Observing tearing artifacts on Roku-4 with 4k @ 60fps HEVC stream

EnTerr:
"It doesn't matter" [img=15x15]https://forums.roku.com/images/smilies/icon_smile.gif[/img] I mean Vsync-ing is a very low level thing in producing video signal (below roScreen, OGL, video decoding). It's not configurable. And if it's that and there were a way to disable the "adaptive" mode of Vsync - mind you that would be worse overall because it will decrease effective FPS.

"EnTerr" wrote:
I understand the annoyance when asked to provide sample for something "obvious" but it may help your case. Metaphorically, you know how "class lawsuits" cover everyone from a group? Well they still need a few real humans as "representatives" in the court proceedings, to represent the plaintiff class. The picture you showed is a simulated("fake") image from wikipedia, not the real effect - it would be good if there is something tangible for a Co' person to look at.

"EnTerr" wrote:
That is a good question, though that by itself would not cause tearing.

"kmayur" wrote:

"RokuMarkn" wrote:
What do you have selected under Settings > Display Type?

--Mark

Thank you, @Mark 🙂 . We have tested with both 4K-8bit and 4K-10bit options under Settings > Display type. Please note, we are using 4K-8bit content for testing.

To give a brief note on our testing,
1) We have tested by connecting Roku to a different HDMI ports on the TV and also tested with different HDMI cables.
2) We have played the same 4K@60fps content on the same TV with a different media player device (Not Roku). It plays without any issues. So, it is not the issue with the HDMI port or HDMI cable.
3) We have also tried rebooting Roku while TV is switched ON.

Please let me know if you think any other tests to be done.

"RokuJoel" wrote:
After chatting with @RokuMarkN I've filed a bug with the media team on your issue, linking to this thread.

 - Joel

1. As you know, Roku4 has two 4K configurations under Settings > Display type.
   (a) 4K UHD TV (10-bit): In this mode, GetVideoMode returns 2160p30. Also call to CanPlay4K() prints "HDCP version too low". I didn't find a way to check current HDCP version so I called IsHdcpActive() with standard HDCP versions. I found that my Roku's HDCP version is 1.4.      
   (b) 4K UHD TV: In this mode, GetVideoMode() returns 2160p60. Also call to CanPlay4K() prints "HDCP 2.2 check passed: ".


2. I have a 4K-UHD-10bit HDR @60fps HLS stream with HEVC video codec stored on a local server. I played this stream using "customvideoplayer" with both the display types.
   (a) 4K UHD TV (10-bit): Video was played at 4K resolution but at around 30fps. Also, the video had tearing issues.       
   (b) 4K UHD TV: Video was played at 4K@60fps. But video quality was not good. It could be because I played 10-bit video in 8-bit configuration.


3. I converted this 4K-UHD-10bit HDR @60fps HLS stream to MP4 and stored it on the same server. I played it using "customvideoplayer" with both the display types.
   (a) 4K UHD TV (10-bit): Video was played @60fps but in a lower resolution. It appeared as if Roku was re-sizing a 1080p video for 4K display. I set Display Type to 1080p HD TV and played the same video. The video quality appeared to be the same.       
   (b) 4K UHD TV: Video was played at 4K@60fps. But video quality was not good. It could be because I played 10-bit video in 8-bit configuration.


4. I copied the MP4 file to a pen-drive. I connected the pen-drive to the Roku and played this content using roku-media-player with both the display types. My observations in this experiment are same as MP4 playback using "customvideoplayer".

1. As per my understanding, HDCP is related to Hardware+Software media pipeline from media receiver to rendering. In observation#1, I am not able to understand how and why changing display type is affecting the HDCP version.


2. From observation#2, #3 and #4, my conclusion is that, Roku supports 4K-10bit @30fps and 4K-8bit @60fps.
   (a) Is this the case?       
   (b) If yes, are there any reasons for that?       
   (c) If 4K-10bit@60fps media is in MP4 format, Roku appears to be re-sizing video to 1080p and playing @60fps. If the media is in HLS format, it appears to be playing at same resolution and frame-rate and failing due to some limitations. Why is there a difference in behavior? Is Roku using different profiles/media engines for MP4 and HLS?


3. I checked GetVideoMode() and found that there are some strings for 10-bit display (Ex: 2160p30b10, 2160p60b10). I don't understand why I am not getting this output even when I set Display type to 4K UHD TV (10-bit).