Can't play 5.1 PCM

[crusher11 851]

Just tried playing the 2009 Royal Rumble, which has a 5.1 PCM soundtrack. My receiver did display "PCM" on the front display, but there was no sound. Forcing a lower quality got me Dolby Digital audio and I could hear it.

 

Why won't this correctly direct play? If it can't, why doesn't it transcode the audio?

[Luke 37064]

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

https://emby.media/community/index.php?/topic/739-how-to-report-a-problem/

Thanks !

 

@@SamES

[crusher11 851]

Here's the log.

embyserver.txt

[SamES 890]

If it is DirectPlaying, and the receiver is displaying PCM, but no sound, this sounds like the TV is not sending the data correctly or it's not supported.  Are there any audio PCM/pass through settings in the LG TV settings you can adjust?  Otherwise, we need to disable the PCM support so that it always remuxes the audio.  If I recall, 5.1 PCM will be a large, uncompressed bitstream which might not be supported via ARC/HDMI so this may need remuxing.

 

If you've got a remux or transcode log for this file, could you please attach it as well.  Alternatively, please provide the mediainfo for this file from the bottom of the details page on the server for this item.  Thanks.  Feel free to send me a sample file as that will definitely help

Edited December 27, 2019 by SamES

[crusher11 851]

@@SamES 5.1 PCM must obviously be capable of transmitting over HDMI, or the Blu-ray wouldn't work. But as it stands, I have an optical audio cable running from my TV to my receiver. There are three transcoding logs, not sure why. I think I've attached the correct files.

 

I started playback from a chapter point, not the start of the file, in case that's relevant.

ffmpeg-transcode-d69fbd39-e30f-461e-82b0-a26dc094c2a8_1.txt

ffmpeg-transcode-0699ec58-95a7-47a4-88f3-3eb64df429b8_1.txt

ffmpeg-transcode-142341b1-46bf-4bf2-9640-05359db2cad7_1.txt

[SamES 890]

Don’t confuse audio from the bluray to the TV via HDMI with audio from the tv to the receiver which uses the audio return channel (ARC) over HDMI. ARC can’t support the same bandwidth and bitrate as the other way around.

 

5.1 uncompressed PCM is too high a rate for ARC, Sonu expect this is the issue but will look at the files tomorrow

[crusher11 851]

@@SamES Like I said, I'm using optical, not HDMI, from the TV to the receiver.

[SamES 890]

I think you will find optical has similar limitations

[SamES 890]

https://www.lifewire.com/digital-optical-connection-1846881

[crusher11 851]

So there's no way to get 5.1 PCM from my TV to my receiver? Shouldn't it be transcoded by the app then, rather than forcing me to also transcode the video, decreasing the quality, in order to hear anything?

[Luke 37064]

Well yes it should be transcoded, but not for users on HDMI. We'll have to see if LG provides a way for us to detect that.

[crusher11 851]

I don't believe HDMI out supports 5.1 at all on my C6 OLED, so the TV would downmix to stereo anyway.

[SamES 890]

If you have a HDMI input on the TV that supports ARC, I would suggest trying that connection to your receiver and see whether that helps.  Generally I've found better support via arc than optical.  But you're right, you still may not get 5.1 PCM, but overall I think it will be a better outcome.

 

https://www.lg.com/ca_en/support/product-help/CT20098005-1437136302910-others

 

I think you won't get DD+ via optical, but you will via ARC/HDMI.  If you use Netflix this is a big advantage

[crusher11 851]

What do I need Netflix for? I have Emby.

 

I tried remuxing it with new audio myself in MKVToolnix, and replaced the file. Now it won't play at all.

 

I didn't realise initially that when I bumped down the quality settings last night, in order to force a transcode and allow the audio to play, that it applied a new server setting rather than simply applying it temporarily (as I did it via the OSD during playback). So I tried to play Royal Rumble 2009, it didn't work, I bounced around a few other WWE events to see if they worked, realised my settings were wrong and that they were all transcoding, changed my setting back to "auto", verified that a Blu-sourced WWE event would direct play, the tried the Royal Rumble again. So, apologies, the log will be a bit of a mess.

 

All I got was a black screen. Had to kill the TV to get out. Then had so many instances of ffmpeg tying up my computer I couldn't do anything - even opening Task Manager took a minute or two - and had to kill them manually after a while because they didn't seem to be going away on their own, even after restarting the server.

embyserver-63713252514.txt

[crusher11 851]

Actually, scratch that. I redid the audio, muxed it, tested it on my PC in VLC, it worked fine. Messed around with the headers to set default tracks etc, imported into Emby, didn't work on my TV. Went back, didn't work on my PC either. Obviously screwed up something with the headers.

 

Redid the new audio mux - thankfully I'd kept the files - and re-imported to Emby, and it works fine now. Full audio on my LG TV while direct playing.

[Luke 37064]

Well done.

[SamES 890]

Great job, thanks for the feedback. Yes, be aware that if you change the quality setting during playback it is a device/user setting that sticks and is applied in subsequent playback on that device. You need to manually change it back to auto. I can see why this setting sticks, and for some use cases that makes sense, but I know for myself if I have change it, it’s really something I want changed just for that title. I’ve been caught out with that as well. Maybe for TV devices, especially on the local network the change should only be temporary (as compared to a user on a mobile device that is roaming) but I guess two different modes of operation would cause a whole new level of confusion.