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Audio: LFE and Center channels being switched

PostPosted: Wed Mar 18, 2015 10:45 am
by Faris Ruhi
Hey there, I have a Decklink 4k Extreme Card and I've just begun to capture games.

I've noticed that when capturing from the PS4 (using HDMI), the LFE and Center Channel seem to be switched. Now I know I can switch the channels after capturing, but the thing is the output coming from the card is also doing the same thing, meaning when I'm playing, I can't hear the stuff that should be on the center channel at all, which means all dialogue, many sound effects etc, which is a problem. If this was one of the surround channels I probably wouldn't have any issue with it, and fix it in post.

When my PS4 is connected to an AV receiver or TV, audio is perfectly fine, I can hear all the contents of the center channel, Decklink seems to be interpreting the 5.1 audio wrong. I tried capturing in stereo as well, but that doesn't fix the problem, and I've tried both the 7.1 and 5.1 options in the ps4.

This is through both Blackmagic Media Express and Adobe Premiere Pro CS 6.

I figured that maybe this was discovered already and updated, so I tried to update my desktop video version, but the thing is doing that seems to cause problems, and just shows a black screen for the ps4, but outputs the video to the tv okay.

So currently I'm using the latest version that allows me to capture video properly, which is Desktop Video 9.9.6.

So any way to adjust or fix this somehow.

Edit: Also for the heck of it, installed the new desktop video software, captured a clip (meaning a black screen) with the audio, the audio still has the same issue, LFE and Center channels are switched, and the output through Media Express also seems to have the issue since again I can't hear any dialogue (which I know is there when I can obtain it in Premiere by switching the LFE and Center channels).

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Mar 20, 2015 3:24 pm
by Tony Rivera
I'd suggest sending an email to your regions support office so we can take a closer look into this.

Re: Audio: LFE and Center channels being switched

PostPosted: Thu Mar 24, 2016 2:36 am
by Rob Cork
I'm having this exact same issue while trying to capture video from my Xbox One. Center and LFE are swapped. I've emailed support and they just say that it must be coming out of the Xbox that way and my Denon receiver is somehow interpreting it correctly but the Intensity Pro 4k isn't. Seems fishy because if the Denon is hooked up to the Xbox directly, the audio is correct. If i connect the Denon to the HDMI-out of the Intensity Pro 4k, the channels are swapped. For now i'm using ffmpeg to remap the audio channels correctly but it's a pain in the process and the product should just work as advertised.

Re: Audio: LFE and Center channels being switched

PostPosted: Thu Mar 16, 2017 11:33 pm
by Erwan Robert-Thomasson
hi,
the problem is still here. i just got a 5.1 setup and can't use nor the sdi nor the hdmi audio embeded for 5.1 audio, center and lfe are swaped...
gonna have to get a dac...

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Mar 17, 2017 8:42 am
by Xtreemtec
You could run it trough a decimator MD-HX. In this box you are able to swap audio channels in the hdmi or sdi..
Even can use this box to loop trough to your receiver and Go SDI Out to your decklink Card..

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Mar 17, 2017 8:53 am
by Erwan Robert-Thomasson
thanks xtreemtec,
that's what i need indeed, but feel a bit pricy just to correct a bug...

Re: Audio: LFE and Center channels being switched

PostPosted: Sat Jan 19, 2019 2:29 pm
by KatieKate
I'm having the same problem with a UltraStudio 4K and Media Express 3.5.7. After much searching, I found that I can use ffmpeg to create a new file with the LFE and C channels swapped (i.e. corrected).

Code: Select all
ffmpeg -i input.mov \
-filter_complex "pan=6c|c0=c0|c1=c1|c2=c3|c3=c2|c4=c4|c5=c5[out1]" \
-map 0:0 -c:v copy \
-map [out1] -c:a pcm_s24le \
output.mov

Notes:
- The input.mov and output.mov file names must be replaced by hand in the command.
- The command assumes output written by Media Express. If the file was manipulated and written anew by Final Cut X, change the -map 0:0 to -map 0:1. This is required because ME writes audio as stream 0, whereas FCX writes video as stream 0 and audio as stream 1.
- The command assumes a 5.1 input file, and will write out a properly ordered (L, R, C, LFE, Ls, Rs) file. The actual magic happens with the c2=3|c3=2 part of the --filter_complex flag.

On macOS, ffmpeg can be installed using Homebrew.

Re: Audio: LFE and Center channels being switched

PostPosted: Thu May 02, 2019 5:10 am
by Mike Wolf
This is still an issue.

Just bought an SDI to HDMI 6G Mini Converter.

LFE and Center swapped when sending SMPTE Surround L/R/C/LFE/LS/RS.

I can route 3 to 4 and 4 to 3 in my output matrix, but that's just for monitoring/playback. Obviously need correct routing for mastering.

BMD please fix!

Re: Audio: LFE and Center channels being switched

PostPosted: Thu May 02, 2019 10:36 am
by Xtreemtec
Mike Wolf wrote:This is still an issue.

Just bought an SDI to HDMI 6G Mini Converter.

LFE and Center swapped when sending SMPTE Surround L/R/C/LFE/LS/RS.

I can route 3 to 4 and 4 to 3 in my output matrix, but that's just for monitoring/playback. Obviously need correct routing for mastering.

BMD please fix!

Send it in as a support ticket! Because this is a user forum.. Only if a lot of people have the same issues it is picked up from here. ;) But things this rare need a support ticket to get on the bugfix list.

Re: Audio: LFE and Center channels being switched

PostPosted: Mon Oct 28, 2019 5:55 am
by Tom Jones
Mike Wolf wrote:This is still an issue.

Just bought an SDI to HDMI 6G Mini Converter.

LFE and Center swapped when sending SMPTE Surround L/R/C/LFE/LS/RS.

I can route 3 to 4 and 4 to 3 in my output matrix, but that's just for monitoring/playback. Obviously need correct routing for mastering.

BMD please fix!


Yep 6G converter doing the same thing here too. Center channel playing through the LFE and vice versa. Blackmagic QC obviously not what it use to be.

Re: Audio: LFE and Center channels being switched

PostPosted: Tue Nov 26, 2019 2:42 am
by Tom Jones
I love how this thread is over 4 years old and this problem is still an issue.

I have no idea why the default is to keep it as SMPTE L/R/C/LFE/LS/RS when outputting through HDMI, when 99.9% of HDMI devices people will be using it on require CEA L/R/LFE/C/LS/RS.

For those who need a timely solution, I have been in contact with AJA and they are far more helpful. They are totally aware of this and have convertors that are switchable between the 2 standards. We are currently in the process of changing out the 10 Blackmagic edit suites we have with AJA hardware.

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Dec 13, 2019 1:23 pm
by videotonart
Brand new Decklink 12G extreme.

HDMI input (or at least the inputs in Media Express) switches channels 3/4 around at the input.
Somewhat embarrassing that this bug is already so old.

Whatever the standard, channels should be mapped straight, 1->1, 2->2, 3->3 etc.
Now channels 3 and 4 are being reversed, which is not helpful.

Can this be fixed finally please?

Carl.

Re: Audio: LFE and Center channels being switched

PostPosted: Wed Jun 17, 2020 3:37 am
by Jonathan Spafford
Did this ever get fixed? I was thinking about getting a AVR with multichannel in and use my HDMI 7.2 audio breakout box just so I can physically switch channels 3&4.

Re: Audio: LFE and Center channels being switched

PostPosted: Thu Jun 18, 2020 4:45 am
by Peter Chamberlain
Carl, did you check the admin utility? I recall there is a tick box in the admin utility to enable/disable swapping audio channel 3 and 4 on HDMI in/out and i think this is also documented in the user manual.

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Jun 19, 2020 2:23 am
by Jonathan Spafford
Peter Chamberlain wrote:Carl, did you check the admin utility? I recall there is a tick box in the admin utility to enable/disable swapping audio channel 3 and 4 on HDMI in/out and i think this is also documented in the user manual.



It was an option in the manual and only for the ultrastudio. There wasn’t that option on decklink or intensity. Why it’s a bug. Someone forgot to include us. I imagine it’s a cut and paste of a handful of lines of code.

Re: Audio: LFE and Center channels being switched

PostPosted: Fri Nov 13, 2020 10:17 am
by rodoworks
This is a really annoying bug even with an Ultrastudio; switching works only on HDMI but not on the SDI.
And with 20meters between the machine room and my suite, 12G SDI is the only solution that makes sense..
I tried the 12G Cross from Decimator but you can only switch audio pairs...so that doesn't solves it either..
As I doubt this bug will be fixed in the near future, are there any other solutions to swap embedded audio by channel ?
Any help appreciated; thx !

Re: Audio: LFE and Center channels being switched

PostPosted: Sat Nov 14, 2020 5:16 am
by Peter Chamberlain
It’s not a bug. There are two hdmi standards and the utility lets u switch those.
No switch for SDI as there isn’t conflicting standards.

Re: Audio: LFE and Center channels being switched

PostPosted: Thu Dec 10, 2020 6:59 pm
by lanoso_grande
Peter Chamberlain wrote:It’s not a bug. There are two hdmi standards and the utility lets u switch those.
No switch for SDI as there isn’t conflicting standards.


Where is that option? I'm not seeing it in the "Blackmagic Desktop Video Setup"
[Mini Monitor 4K, Desktop Video 11.6, Mac OS 10.14.6]

Edit: Or in 11.7 (or the 12 Beta which, incidentally, would prevent Media Composer from loading)

Re: Audio: LFE and Center channels being switched

PostPosted: Sun Feb 14, 2021 4:13 am
by oneamadio
Encountering this now in Blackmagic Media Express on Mac with a Decklink Quad HDMI recorder. The channel mapping is super annoying as the default Quicktime export options I've been using for quickly compressing down to H264 results in a file with completely incorrect mapping, and Compressor supports many different channel mappings but NOT the specific one with 3&4 swapped that comes out of the Blackmagic software. Now I'm basically redoing my own channel mappings and having to rebuild the file every single time.

Really wish Blackmagic Media Express had some audio options like channel mapping and sample rates (recording in any 44.1k music source over HDMI gets interpreted as the 48k default and ends up pitched up in the final file), but at least just switching the channels would be a massive improvement to my workflow

Re: Audio: LFE and Center channels being switched

PostPosted: Wed Feb 17, 2021 5:13 am
by lanoso_grande
Yep. Please address this guys... This is not the only thread on this issue - Clearly a problem.