OBS Decklink Output - 8 Audio Channel Support?

[regstuff]

Hi,
I'm trying to output a multichannel audio source via a blackmagic decklink mini monitor. It support upto 8 channels of embedded audio. However, when I try to "play out" a multi-channel source, I only seem to be able to output the first 2 channels. The decklink is outputting via an SDI cable to a Blackmagic mini recorder which can handle 16 channels of audio.
OBS Audio settings are set to 4.0. The audio source also has 4 channels of audio.
Is there any restriction in the OBS Decklink to just stereo?

 

[sudogamer]

I thought i was going crazy with this question alone.

Its 2025 and 7.1/8 channel audio is still not supported by OBS for decklink devices. I was able to get 8 channel audio to work with ffmpeg but it uses way too much resources and practically unusable for long time streaming / recording.

#below command converts 8 channel input to 6 channel output
ffmpeg -hide_banner -format_code 23ps -rtbufsize 2G -channels 8 -f decklink -i 'DeckLink 8K Pro (1)' -filter_complex "[0:a]pan=5.1|FL=FL|FR=FR|FC=FC|LFE=LFE|BL=BL+SL|BR=BR+SR[a]" -map 0:v -map "[a]" -vcodec hevc_nvenc -vprofile main -preset p7 -pix_fmt yuv420p -multipass fullres -2pass true -tune hq -rc constqp -qp 19 -rc-lookahead 40 -lookahead_level 3 -c:a eac3 -ar 48000 -ab 768k -ac 6 -f matroska - "out.mkv" | ffplay -hide_banner -

 

[rockbottom]

Surround has worked fine for me with OBS for years. I must be doing something right.

Decklink is sending "matrixed" surround to OBS so your results are expected. Step up to discrete audio & you won't have that problem.

Taken right from the Decklink specs.

HDMI Audio Outputs​

8 Channels embedded in TMDS.
32 Channels embedded in FRL

Understanding TMDS and Its Role in High-Speed Data Transmission

Learn how TMDS encoding reduces EMI and improves high-speed data transmission for digital video signals.

www.jtechdigital.com

Surround Sound Guide | OBS

OBS Knowledge Base. Learn how to make streams and recordings with surround sound

obsproject.com

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