LG TV Capability - Does Emby have to Transcode Live TV?

[PeteD 2]

My LG Smart TV (OLED65B8SLC) is able to take the same feed from our terrestrial areal that I send into TVHeadend.

I'm wondering why Emby transcodes channels that the TV is quite clearly capable of supporting?

The profile from TVHeadent to Emby is Passthrough 

In all instances that I've seen Emby transcodes the audio from AAC_LATM to AAC.

Is there any way to tell Emby the TV supports AAC_LATM so I can test if it works without transcoding (or am I missing something here)?

 

Thanks

[Luke 37094]

Hi, you could temporally restrict user access to transcoding in order to test this. Just make sure to undo the change because it will likely cause playback failures with other content. Please let us know the result. Thanks.

[PeteD 2]

Thanks for the advice... I've tested and can confirm that the TV plays audio without the need for transcoding: @SamES

Before...

 

After...

 

I'll keep testing a little longer but looks positive. Is there a 'next step' available to stop transcoding just this codec?

Many Thanks!

[SamES 891]

Actually, something to be aware of.

Specifically to LG, if the TV doesn't support the selected audio track - regardless of the settings in Emby - the TV will automatically select the next supported audio track if there is one.  It doesn't inform Emby of that, so we aren't aware that it has occurred in the player and we will still report the originally selected track

So, if you have AAC_LATM and an AC3 track and select AAC_LATM in Emby, if the TV detects it can't play it then it will automatically play the AC3 track.  We will assume the selected track (AAC_LATM) is the one being played, but that will be incorrect.  This happens with Emby and the built in player as well.

The only way to really test this is using a file with only a single AAC_LATM track.

If you make a recording with these tracks, can you please send me a short sample (a few minutes) to test?  For your own test, try removing any non-AAC_LATM from the recording and check that it still works for you.

FWIW, on Samsung we have had to recently disable AAC_LATM as it doesn't appear to be supported (or doesn't work correctly) on recent models.

This is something that may also be the case on LG, which is not so easy for us to check and confirm.

[PeteD 2]

I'm a little confused with this. If a transmission has multiple audio channels, I see the music icon within Emby and get to choose what channel to listen to - usually one is NAR (Audio description for sight impaired) and the other for the standard audio. As I select this within Emby how can the TV get to select the other track if it doesn't support the codec?

Anyhow, it's fair to say that within TVHeadend I have a filter to remove the NAR audio so only a single track is delivered to Emby at that point (and I don't see the music note icon as there isn't anything to select).

I've checked a recording I made the other day (this recording would normally be transcoded but is I disable the ability to transcode it still plays without issue) and it shows just a single audio AAC_LATM track:

[SamES 891]

2 hours ago, PeteD said:

I've checked a recording I made the other day (this recording would normally be transcoded but is I disable the ability to transcode it still plays without issue) and it shows just a single audio AAC_LATM track:

Then it's probably supported - at least on some models.

2 hours ago, PeteD said:

As I select this within Emby how can the TV get to select the other track if it doesn't support the codec?

The app will always show all audio tracks - but if it's not supported it will transcode rather than direct play when you select one of those tracks

[emveepee 112]

Don't know about the LG or this broadcast source ,but one of the issues I have found with with various players and AAC and HE-AACv2 was the lack of support for multi-channel audio.  This isn't something that a PVR can auto detect with a sample at the beginning since it varies by show and commercial.  Same sort of issue with the stupid BBC interlaced/progressive feeds.

Martin