4K video playing at 1080p

[kaledi 41]

HEllo - not sure this is the correct sub-forum to place this issue.

I have Emby Server on a Synology NAS and the main clients we stream to are a Shield TVs.  I have refresh rate and resolution switching on and for pretty much all my media this works perfectly.  I have however got a couple of 4k videos that for some reason play fine, but cause a resolution switch to 1080p.

I've attempted to remux and even re-encode e.g. from AVC to HEVC, but it makes no difference.  One of the files is Depeche Mode 101 (official download as part of a recent release) that is in 4:3 aspect ratio.

Any other reported issues of this kind?

[ebr 16169]

 

Hi there, let's look at an example. Please attach the information requested in how to report a media playback issue. Thanks!

 

[kaledi 41]

Thanks.  Apologies for the slow reply.

Here is part of one of the problem files.  This plays fine, but only at 1080p.

I've also transcoded into HEVC the same file and the same behaviour is apparent.  I can upload a log file if that helps.  Do you need the server log, or media player log file?  Should debug mode be on for a the server log file?

180193392_DepecheMode101(1988)-(4Kmkv).mkv

[visproduction 315]

The test video shows 2880 x 2160.  This is a a little larger than the inbetween size 2K. I thought 4K is recognized when the resolution is, at least, 3840 wide.  I assume the label of 4K is pulled from the width in Emby.  That seems to be how it works for all the other sizes.  I think maybe the situation is the video can play back properly at it's full resolution, depending on your monitor, but it does not get the label of 4K at 2880 width.  On a TV, there may be some other issue.  Unless it is really 3840 wide, then it snaps back into 1080P because the TV is just not interested in playing back content in between, or it is set to auto upscale and then calls the original content 1080 in the playback info.  I hope that makes sense. Ha!

Edited December 15, 2021 by visproduction

[kaledi 41]

Thanks for the response. I thought 4k was defined by the vertival resolution. This is a 4:3 video hence the shorter horizontal resolution. It's not as if the 1080p resolution plays at 720p. More to the point 2880 is still considerably larger than 1920 so emby should still treat it at 4k in my view 

[kaledi 41]

Regarding the TV. There is no issue. This is to do with the output from the shield. I can't claim that the shield is doing something it shouldn't. I'll see if I can test on an alternative device to output to a TV 

[ebr 16169]

Can you please play that item for a few seconds and then follow the instructions to send a log from the app?

 

[kaledi 41]

From the shield TV app - correct?

 

[kaledi 41]

As an additional piece of information.  I played this video back successfully via PLEX (with refresh rate switching and resolution switching both enabled) - the other video I have a problem with also plays correctly on PLEX.

[RanmaCanada 494]

Although this is a 2160p resolution, it is not a 4K resolution, so it is possible your TV is unable to play it back and thus that is why it is being shrunk down to 1080p.  I would strongly suggest you check your TV manual for supported resolutions. 

As for PLEX, we already know they screw around with things during playback.  

Edited December 14, 2021 by RanmaCanada

[kaledi 41]

TV is fine.  This is a 4:3 4K video as far as I am concerned.  It is a 4K tv and I have no issue playing any other video with resolution switching and I've just shown that it plays correctly via PLEX

[kaledi 41]

19 minutes ago, ebr said:

Can you please play that item for a few seconds and then follow the instructions to send a log from the app?

 

Thanks.

I've submitted logs.  First with this video playing and then I played the other video that drops to 1080p and also submitted a log for that one.

[RanmaCanada 494]

Just because it "plays fine in PLEX" means nothing.  Again this is not a standard 4k resolution and is not even in the spec.  

[ebr 16169]

27 minutes ago, kaledi said:

then I played the other video that drops to 1080p and also submitted a log for that one.

Quote

Then add the following information to your report in the forum:

 

• Exactly what you were doing and what happened.  Include the name of whatever you played if it is a playback problem
• The time you sent the log (in Eastern Time please - UTC -5)
• The name of the Emby user on the local server that was logged in at the time

 

[ebr 16169]

Hi.  I may have found your logs but, if so, neither one shows the start of playback.  Please just start playback for a few seconds then send the log directly from the OSD during playback and provide the above information.

Thanks.

[kaledi 41]

Sorry for that. I've now resent two sets of logs one for each video 

[ebr 16169]

Yeah, this is a tricky one.  It is because it is 4:3 so it is fooling the system into thinking it is less than 4K.  It is very rare to have 4K content in a 4:3 aspect.  I can see that the system is already running in 2160/23.97 so you can probably just turn off the auto switching and be good.

[kaledi 41]

36 minutes ago, ebr said:

Yeah, this is a tricky one.  It is because it is 4:3 so it is fooling the system into thinking it is less than 4K.  It is very rare to have 4K content in a 4:3 aspect.  I can see that the system is already running in 2160/23.97 so you can probably just turn off the auto switching and be good.

Thanks - yes I thought that may be a solution.  I agree it is rare, but not completely unknown.  Other than some old material being encoded at 4:3, you also can set some DLRs/Mirrorless cameras to shoot in 4K 4:3, which would produce the same resolution.  Is this something can could be logged to improve the playback behaviour.

 Could you also check the second log file.  That one is supposed to be 16:9 and is 4K but plays at 1080p.

[ebr 16169]

57 minutes ago, kaledi said:

Is this something can could be logged to improve the playback behaviour.

Since you are already in 4K/23.97 I don't think you need to do any refresh rate or resolution switching at all.  What are you trying to accomplish by having that turned on?

[kaledi 41]

I have material of different resolutions and frame rates so frame rate matching is critical.  I'd also rather allow my TV to do any upscaling therefore match the resolution too.  I can set resolution matching to off in order to watch this video of course but that is annoying, and certainly would not want to have it switched of permanently

[ebr 16169]

5 minutes ago, kaledi said:

I have material of different resolutions and frame rates so frame rate matching is critical.

Have you tried without it?  Since you appear to be running in 23.97 by default, it may not be as critical as you think...

[kaledi 41]

Yes, I have, and indeed one of the great features of EMBY is that it does support frame rate switching.  Living in Europe a great deal of material is in 25 or 50 fps and playing such material at any other framerate is dreadful.  Streaming apps don't support framerate switching internally on the Shield TV, and it is very noticeable.  There is a practical work around using a third party app, but this can cause HDMI handshake issues in some apps on changing frame rate but it is still far more preferable than not having it.

[hjason7812 34]

On 12/14/2021 at 10:59 AM, visproduction said:

The test video shows 2880 x 2160.  This is a a little larger than the inbetween size 2K. I thought 4K is recognized when the resolution is, at least, 3840 wide.  I assume the label of 4K is pulled from the width in Emby.  That seems to be how it works for all the other sizes.  I think maybe the situation is the video can play back properly at it's full resolution, depending on your monitor, but it does not get the label of 4K at 2880 width.  On a TV, there may be some other issue.  Unless it is really 3840 wide, then it snaps back into 1080P because the TV is just not interested in playing back content in between, or it is set to auto upscale and then calls the original content 1080 in the playback info.  I hope that makes sense. Ha!

this is a 4k resolution 2160p is 4k the 2880 is due to being a 4:3 frame and not a 16:9 and so on. here is an example of 4k resolutions.

 

"As things stand, the majority of 4K displays come with 3840 x 2160 pixel (4K UHDTV) resolution, which is exactly four times the pixel count of full HD displays (1920 x 1080 pixels). There are also 4096 x 2160 pixel (DCI 4K) displays for the film industry that are referred to as 4K displays."

[hjason7812 34]

On 12/14/2021 at 1:35 PM, RanmaCanada said:

Just because it "plays fine in PLEX" means nothing.  Again this is not a standard 4k resolution and is not even in the spec.  

As things stand, the majority of 4K displays come with 3840 x 2160 pixel (4K UHDTV) resolution, which is exactly four times the pixel count of full HD displays (1920 x 1080 pixels). There are also 4096 x 2160 pixel (DCI 4K) displays for the film industry that are referred to as 4K displays.

4k is 2160p but his had the freak 2880 for the width it is still 4k resolution though even though it is 4:3 and not 16:9