Hooray! Hardware decoding is fixed in 4.6!! (Update: Not really)

[C.S. 93]

For the longest time I had to disable hardware decoding for h.264 under Advanced transcoding settings in order to avoid the occasional green line artifact at the bottom or sometimes right side of the screen. (Quicksync UHD 630) But now since upgrading to 4.6.4, everything just works when I set Transcoding to Yes instead of Advanced. Awesome! Thanks guys!

Somewhat related question: I assume the h264 encoding preset and CRF settings only apply to software transcoding. Correct?

Edited August 2, 2021 by C.S.

[Carlo 4561]

Hi, yes correct on the presets.

You can change the option from Yes to Advanced if you like.  Advanced will show you which encoders/decoders it choose to setup for you.

[C.S. 93]

Dang. Spoke too soon. Green line is still there, just not with the particular title I was testing with before. Oh well, back to software decoding. Not a big deal.

For some reason the green line goes away when I set the bitrate (client side) to 3mb or less.

Anyway like I said not a big deal since decoding is not super resource intensive.

[Happy2Play 9785]

I would have to say media specific as I do not see this behavior on my UHD 630.  But I leave mine on Advanced with only QuickSync Intel(R) UHD Graphics 630 - D3D11 options enabled as I RDP into my headless servers a lot and mess up the yes option.

[Luke 42085]

2 hours ago, C.S. said:

Dang. Spoke too soon. Green line is still there, just not with the particular title I was testing with before. Oh well, back to software decoding. Not a big deal.

For some reason the green line goes away when I set the bitrate (client side) to 3mb or less.

Anyway like I said not a big deal since decoding is not super resource intensive.

Hi there, can we please look at an example?

Thanks.

[C.S. 93]

6 hours ago, Happy2Play said:

I would have to say media specific as I do not see this behavior on my UHD 630.

Yes for sure this only happens with a limited number of files, and I've almost only seen it happen when playing through an android tv client. (I say almost because I'm sure I saw it happen on a roku, but only once that I can think of.)  4:3 and 2.4:1 files are really the only ones where it's even possible to show up, since overscan hides the edges of 16x9 files. The green line is only a pixel or two wide, always on the bottom edge for a 2.4:1 and on the right side of a 4:3. The thing that threw me is that the movie I saw it happen with most consistently is now fine since the 4.6 update; I can't get the green line to show up again at any bitrate, so I thought the issue must have been fixed. But then yesterday I just happened to see it with a different file.

4 hours ago, Luke said:

Hi there, can we please look at an example?

Yeah I was afraid you'd ask for that. I really appreciate the offer to help, and I'd love to assist in squashing a bug, but for me the workaround is so simple (disable both QS options under H264 decode) that I just can't see spending any real time on it. But short of a log file or screenshots, I'm happy to provide any info I can. Maybe if I went through my collection I could put together a list of affected files and find some commonality in them, but I just ummmmm... don't see that happening.

[softworkz 5073]

The green that you're seeing is kind of "the black in yuv formats".

QSV needs image sizes to be multiples of 16 or 32 ( depending on case and API version) for internal processing.

Normally this is handled automatically, but there might be an edge case bug. What you could look at for identifying a pattern associated with that problem are the image sizes. Check whether width and height modulo 16 is equal to zero and otherwise note the result. Compare the modulo results from working and non-working videos. 

It's a test that might get interesting but it could also be a dead end..

[C.S. 93]

17 hours ago, softworkz said:

It's a test that might get interesting but it could also be a dead end..

For the past couple years I've been using a certain file (1920 x 816, green line appears on bottom) to check to see if this issue persists. Since the 4.6 update, that file is perfect with QS decoding turned on. Then the other day I started a transcode with a different file (1520 x 1080) and it showed the green line on the right side. Since your post I've gone through a couple dozen more files, most divisible by 16, some not. I haven't seen any more green lines, but one file (1280 x 546) shows some distortion at the bottom of the image - it looks like one line is being repeated and covering the last 20 or so lines. And once again, turning off QS decoding turns it back to normal.

So I think I've hit my personal dead end with this issue. QS decoding will stay off from now on. Maybe next CPU/GPU I'll give it a try again, but either way it's not a big deal since the hit to the CPU is not that bad.

Thanks everybody Emby still kicks ass.

[softworkz 5073]

Thanks for your reply. I'm glad to hear that you are satisfied with the Emby experience

 

If anybody is experiencing the same and able to submit a sample video, we could further look into this, though.

[C.S. 93]

If you want I can send you the 1520 x 1080 file as it's only 2GB (high bitrate short film). The green line shows up on my android tv box (Mi Box) with QS decoding turned on at any setting above 3 mbit.

[softworkz 5073]

Sure, you can PM me a dl link. Thanks!