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LFE on stereo downmix
Posted: 17 Dec 2019, 08:46
by Uryupinsk
Hi,
I’m using MrMC with an Apple TV 4K connected through an AirPort Express on an analogue stereo system with a subwoofer. I have no possibility to connect the subwoofer to the system other via high impedance inputs. So, with this in mind I have to choose 2.0 as audio output.
My question is does the LFE channel is included in the stereo downmix when 2.0 output is selected? If not, would it be possible to add an option to add it, and the amount of LFE, like in Kodi?
Thanks.
Re: LFE on stereo downmix
Posted: 21 Dec 2019, 12:51
by davilla
When multichannel audio sources are downmixed to 2.0, all channels are included in the downmix. It does not just take the r,l channels and ignore the others.
Re: LFE on stereo downmix
Posted: 21 Dec 2019, 12:56
by Uryupinsk
I just ran some tests with a 5.1 M2TS audio test file, the LFE channel is completely discarded in stereo downmix. This is the default in Kodi too, and Infuse is acting the same.
On OSMC and CoreElec, they added an option to include the LFE channel, and its amount in stereo downmix. I can confirm this is working, because I have a S912 device on CoreElec.
So maybe you could do the same by making it optional, because it could damage the speakers if the user doesn't know what is he doing.
Re: LFE on stereo downmix
Posted: 21 Dec 2019, 13:04
by davilla
Uryupinsk wrote: 21 Dec 2019, 12:56
On OSMC and CoreElec, they added an option to include the LFE channel, and its amount in stereo downmix. I can confirm this is working, because I have a S912 device on CoreElec.
Where is their patch for this ?
Re: LFE on stereo downmix
Posted: 21 Dec 2019, 13:11
by Uryupinsk
The patch originated from OSMC, here is the link to it :
https://github.com/osmc/osmc/blob/c10c4 ... -LFE.patch.
Re: LFE on stereo downmix
Posted: 21 Dec 2019, 19:24
by movdude
I noticed the LFE channel missing too on stereo downmix. The same thing happened in Infuse so not sure if this is an apple thing. This is a good test file if it helps.
https://www.demo-world.eu/download-2d-t ... ssless.jpg
Re: LFE on stereo downmix
Posted: 09 Jan 2020, 14:57
by movdude
I seem to be having some issues after further testing and using 3.9.4. When I select 2.0, I am missing channels, mainly the left side channels, but I do get LFE. When I select 2.1, I get all channels, but do not get LFE with or without the new setting.
I have been testing with the sample I linked in the previous post.
My setup is ATV4k > TV (Sony X900F) > ARC > SoundBar.
I will do some more testing and upload debug logs. Right now, my best option seems to be to set the ATV to output DD5.1 and set MrMC to 5.1 and I seem to get all channels.
Re: LFE on stereo downmix
Posted: 09 Jan 2020, 16:50
by davilla
movdude wrote: 09 Jan 2020, 14:57
I seem to be having some issues after further testing and using 3.9.4. When I select 2.0, I am missing channels, mainly the left side channels, but I do get LFE. When I select 2.1, I get all channels, but do not get LFE with or without the new setting.
I have been testing with the sample I linked in the previous post.
My setup is ATV4k > TV (Sony X900F) > ARC > SoundBar.
I will do some more testing and upload debug logs. Right now, my best option seems to be to set the ATV to output DD5.1 and set MrMC to 5.1 and I seem to get all channels.
waiting for a
debuglog
Re: LFE on stereo downmix
Posted: 10 Jan 2020, 00:01
by movdude
davilla wrote: 09 Jan 2020, 16:50
movdude wrote: 09 Jan 2020, 14:57
I seem to be having some issues after further testing and using 3.9.4. When I select 2.0, I am missing channels, mainly the left side channels, but I do get LFE. When I select 2.1, I get all channels, but do not get LFE with or without the new setting.
I have been testing with the sample I linked in the previous post.
My setup is ATV4k > TV (Sony X900F) > ARC > SoundBar.
I will do some more testing and upload debug logs. Right now, my best option seems to be to set the ATV to output DD5.1 and set MrMC to 5.1 and I seem to get all channels.
waiting for a
debuglog
When testing tonight, it is working properly with 2.0, and the LFE setting is good too. I'm not sure what trouble I was having before, but I restarted the ATV and everything is still good. I apologize and I'll upload a debug log if I see anything odd.
Re: LFE on stereo downmix
Posted: 10 Jan 2020, 14:15
by Uryupinsk
I am looking forward to test the 3.9.4 TestFlight version. I sent an email this morning.
