Trying to locate the bottleneck before buying new hardware

[ryancey 23]

Hi,

I'd like some help to pinpoint the bottleneck when playing 4K HEVC HDR10 files: they don't play well, some start but can't seek, other don't even start.

Regular 4K HEVC files (non HDR10) play well.

Emby uses ~30% CPU when playing, with some rare spikes at ~90%.

The app is Emby for LG 1.0.35 and the TV is a LG OLED55A16LA (with a α7 Gen4 AI Processor 4K that should be able to handle HDR10 according to the specs )

Some specs about the TV:
- https://www.rtings.com/tv/reviews/lg/a1-oled
- https://www.lg.com/uk/tvs/lg-oled55a16la
- https://www.displayspecifications.com/en/model/964f251b

According the the logs, it seems like it is throttling a lot.

What's happening?

I'd be great to understand and known what to look for in the logs so I can debug myself next time!

Thanks a lot.

 

ffmpeg-remux-dc16d90a-ae05-4ea2-a32e-759678c5523d_1.txt

Edited September 27, 2022 by ryancey

[SamES 895]

The issue is that the TV can't play DTS as LG no longer support this format in newer models.  This means that the server needs to convert the audio to a supported format which explains the CPU consumption.

However, 4K/HEVC files, particularly with higher bitrates tend to have stuttering issues during playback.  The limitation here is usually the TV.  Faster server, network, etc will not usually solve it.

Your best option is to select a supported audio track before playback (such as the English AC3 track).  This will allow DIrectPlay of the file with no conversion and all your problems should go away.  If they file does not have a supported track, there are easy ways to create an AC3 track and add it to the file.

[ryancey 23]

48 minutes ago, SamES said:

The issue is that the TV can't play DTS as LG no longer support this format in newer models.  This means that the server needs to convert the audio to a supported format which explains the CPU consumption.

Thanks a lot for spotting this! I didn't know about the LG TVs, good to know. The line in question is

08:08:39.710   Stream #0:1 -> #0:1 (dts (dca) -> ac3 (native))

isn't it ?

49 minutes ago, SamES said:

However, 4K/HEVC files, particularly with higher bitrates tend to have stuttering issues during playback.  The limitation here is usually the TV.  Faster server, network, etc will not usually solve it.

Actually the plan was to get a Nvidia Shield or upgrade my ISP mediaplayer box (both running Android TV).

[ryancey 23]

Quote

DTS-X (pass-through), and DTS-HD (pass-through)

https://www.nvidia.com/en-us/shield/shield-tv/ (Audio section)

What will be Emby for Android TV behavior regarding the fact that Nvidia Shield will pass-through DTS to the TV (that doesn't support it)?

Will it require a transcoding on Emby server? Or the movie will just be muted because the client (Nvidia Shield) does support DTS?

[SamES 895]

32 minutes ago, ryancey said:

Thanks a lot for spotting this! I didn't know about the LG TVs, good to know. The line in question is

08:08:39.710   Stream #0:1 -> #0:1 (dts (dca) -> ac3 (native))

isn't it ?

Correct.

16 minutes ago, ryancey said:

What will be Emby for Android TV behavior regarding the fact that Nvidia Shield will pass-through DTS to the TV (that doesn't support it)?

Will it require a transcoding on Emby server? Or the movie will just be muted because the client (Nvidia Shield) does support DTS?

@FrostByte, what does happen in this case?

[FrostByte 5064]

Currently, the Emby for Android app will do nothing and let the Shield passthrough DTS and hardware convert it to PCM 2.0 if your TV doesn't support DTS.

However, the AndroidTV apps has an option to disable passthrough of DTS and force the server to transcode it to AC3 5.1 for those who have an AVR which supports DD 5.1 and not DTS

There is a feature request to add disabling passthrough of DTS in the standard app also and Luke says something similar will be coming as new development on ATV appears to be winding down.