Pixelated/Blurry/Discolored Playback on Roku when Transcoding

[Xalactic 6]

Emby Server 4.8.8.0 on TrueNAS Scale. Hardware transcoding enabled with Intel i5-13600K. Latest Roku app.

When playing back media while transcoding (due to PGSSUB), the video will often be pixelated and discolored. This is quite noticeable during dark scenes. That's the best I can describe it, so a video is attached. This happens across different movies, shows, and Roku devices. Does not appear to be an issue when watching on my computer. I've tried selecting between auto transcoding options and QuickSync only with no difference. Logs are attached. Not sure if this is a server issue or Roku issue, so please move this if needed. Let me know if I can provide additional information.

Logs/Video: https://www.dropbox.com/scl/fo/ob3l86wwue4w3g6ay4sld/APURuhSuet2h912t3ysvEis?rlkey=chgaofj42qm74g60jeee54rjg&st=vmcv48g4&dl=0

[ebr 16169]

Hi.  That just looks like low-bitrate/poor quality.  Have you tried it without hardware accel?  How about if you turn the subs off and let it direct play?

[Xalactic 6]

31 minutes ago, ebr said:

Hi.  That just looks like low-bitrate/poor quality.  Have you tried it without hardware accel?  How about if you turn the subs off and let it direct play?

I can try software transcoding just to see. It's not low bitrate or poor quality. Looks fine without subs with direct play.

Edited September 3, 2024 by Xalactic

[Xalactic 6]

5 hours ago, Xalactic said:

I can try software transcoding just to see. It's not low bitrate or poor quality. Looks fine without subs with direct play.

@ebrSoftware transcoding did not show the same issue, but the image quality was overall worse and buffered a few times. Switched back to use hardware and am having the same issue as before. Confirmed again that it looks fine with direct play.

[Luke 42077]

@Xalactic

 

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

 

[ebr 16169]

21 minutes ago, Luke said:

@Xalactic

 

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

 

Its all in the first post...

[speechles 2055]

 

• >>>>>> Hardware Decoders for h264
• [ ] VAAPI Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• [X] QuickSync Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• >>>>>> Hardware Encoders for h264
• [ ] VAAPI Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• [X] QuickSync Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)

 

Does it have the same problem with VAAPI?

[Xalactic 6]

3 minutes ago, speechles said:

 

• >>>>>> Hardware Decoders for h264
• [ ] VAAPI Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• [X] QuickSync Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• >>>>>> Hardware Encoders for h264
• [ ] VAAPI Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)
• [X] QuickSync Raptor Lake-S GT1 UHD Graphics - H.264 (AVC)

 

Does it have the same problem with VAAPI?

Yes, same exact issue with only VAAPI enabled.

[speechles 2055]

7 minutes ago, Xalactic said:

Yes, same exact issue with only VAAPI enabled.

https://www.intel.com/content/www/us/en/support/products/219449/graphics/processor-graphics/intel-uhd-graphics-family/intel-uhd-graphics-770.html

Have you gotten the latest drivers as of 8/23/24 and seen if it persists?

 

Oh wait.. linux... let me dig for a minute and find a link to that one.

 

https://www.truenas.com/community/threads/12th-gen-intel-uhd-770-alder-lake-igpu-support.111739/

above is the answer. It isn't supported yet.

Edited September 3, 2024 by speechles

[Xalactic 6]

1 minute ago, speechles said:

https://www.intel.com/content/www/us/en/support/products/219449/graphics/processor-graphics/intel-uhd-graphics-family/intel-uhd-graphics-770.html

Have you gotten the latest drivers as of 8/23/24 and seen if it persists?

As stated, I'm running TrueNAS Scale (latest Dragonfish-24.04.2) so no drivers to install there.

[speechles 2055]

1 minute ago, Xalactic said:

As stated, I'm running TrueNAS Scale (latest Dragonfish-24.04.2) so no drivers to install there.

https://www.truenas.com/community/threads/12th-gen-intel-uhd-770-alder-lake-igpu-support.111739/post-778043

This appears to be where you need to chat to grease the wheels a bit. They are working on it.

[Xalactic 6]

1 minute ago, speechles said:

https://www.truenas.com/community/threads/12th-gen-intel-uhd-770-alder-lake-igpu-support.111739/post-778043

This appears to be where you need to chat to grease the wheels a bit. They are working on it.

Hmm. That's from a year ago and referring to 12th gen Intel. There have been two major versions of TrueNAS Scale released since then and I'm on 13th gen Intel. To be clear, the iGPU gets passed through to Emby no problem. It worked out of the box. Not to say that it couldn't be a TNS issue somehow, but seems unlikely.

[speechles 2055]

If you turn on the stats for nerds in the Roku app it will show if these are dropped frames or stream errors. Once either occurs it starts to count and display them as the media continues playing.

• >>>>>> Video Processing Steps for [0:0]: H.264 (AVC)
• Step HW-Context Format SW-Format Size Next
• H264_QSV >> QSV qsv nv12 1920x1080 >> hwdownload
• hwdownload >> - nv12 nv12 1920x1080 >> format
• format >> - nv12 nv12 1920x1080 >> format
• format >> - yuv420p yuv420p 1920x1080 >> overlay
• overlay >> - yuv420p yuv420p 1920x1080 >> hwupload
• hwupload >> QSV qsv nv12 1920x1080 >>

It has to go through lots of overhead to burn in those PGSSUB. If instead these were SRT the Roku could direct play your media and avoid the problem entirely.

 

I am not sure what the cause is. Does it occur with just software encoding and no hardware encoding used at all? It is definitely something in the pipeline shown above for your hardware transcode.

[Xalactic 6]

5 minutes ago, speechles said:

If you turn on the stats for nerds in the Roku app it will show if these are dropped frames or stream errors. Once either occurs it starts to count and display them as the media continues playing.

• >>>>>> Video Processing Steps for [0:0]: H.264 (AVC)
• Step HW-Context Format SW-Format Size Next
• H264_QSV >> QSV qsv nv12 1920x1080 >> hwdownload
• hwdownload >> - nv12 nv12 1920x1080 >> format
• format >> - nv12 nv12 1920x1080 >> format
• format >> - yuv420p yuv420p 1920x1080 >> overlay
• overlay >> - yuv420p yuv420p 1920x1080 >> hwupload
• hwupload >> QSV qsv nv12 1920x1080 >>

It has to go through lots of overhead to burn in those PGSSUB. If instead these were SRT the Roku could direct play your media and avoid the problem entirely.

 

I am not sure what the cause is. Does it occur with just software encoding and no hardware encoding used at all? It is definitely something in the pipeline shown above for your hardware transcode.

No dropped frames or stream errors. A few posts up, I posted the results of software transcoding (doesn't have this issue exactly, but overall worse image quality and buffering).

[ebr 16169]

This appears to probably come down to the conversion of the original material simply not being very good when using the hardware decoders on that platform.  If you force a web session to transcode by adjusting the bitrate to just below that of the video, does it look the same?

[Xalactic 6]

1 hour ago, ebr said:

This appears to probably come down to the conversion of the original material simply not being very good when using the hardware decoders on that platform.  If you force a web session to transcode by adjusting the bitrate to just below that of the video, does it look the same?

Setting to 1080p 4Mbps in a web session gets it to transcode and looks fine. 720p and 480p look fine, too.

[ebr 16169]

41 minutes ago, Xalactic said:

Setting to 1080p 4Mbps in a web session gets it to transcode and looks fine. 720p and 480p look fine, too.

ffmpeg logs from that to compare?

[Xalactic 6]

47 minutes ago, ebr said:

ffmpeg logs from that to compare?

Created a "Web Transcode" folder in the original Dropbox link. Streamed at 1080p 4Mbps both with subtitles disabled and with them enabled.

[ebr 16169]

Not sure but you are dealing with different display devices in the two instances, correct?

[Xalactic 6]

3 minutes ago, ebr said:

Not sure but you are dealing with different display devices in the two instances, correct?

Correct. Roku is where I'm seeing the issue. You mentioned trying with a web session and I used my laptop for that. However, I will also try lowering the quality on Roku to get it to transcode without the subtitles and see how that looks.

[Xalactic 6]

Interestingly enough, when selecting 1080p 4Mbps on the Roku it looks fine even with the subtitles enabled. As soon as I select Auto and it goes to a higher bitrate, the issue returns. Only had a few minutes to play with it, but I created a "Roku Bitrate Testing" folder with ffmpeg logs from that. I can try other quality settings later if needed.

[ebr 16169]

Interesting.  So it could just be a quirk with the way the hardware encoders are handling transcoding without changing the bitrate.

[Luke 42077]

Hi, are you still able to reproduce this?

[Xalactic 6]

4 minutes ago, Luke said:

Hi, are you still able to reproduce this?

Yep.

[Luke 42077]

OK we're looking into it. Thanks.