Question / Help Which capture cards for surround sound recording

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TO4DM4N

New Member
I've been doing quite a bit of digging, and from what I have read, it seems that my Magewell Pro Capture HDMI card will not allow me to capture surround sound (5.1/7.1) with the latest OBS release and this new feature. I have only seen a few comments on this topic, so my questions:
  1. Is this an accurate statement, that the Magewell card is not supported in OBS for surround sound recording? Seems like Magewell is skimping on driver support for DirectShow and only enabling recording through their SDK? As a few others have confirmed, the card does support 8 channels and I have verified this. But the software is not showing the channels in the mixer.
  2. If correct, which cards are supported by OBS to take advantage of the new surround sound functionality? I'm fairly new to this tech, so open to any suggestions. The only card that seems to support this is the Blackmagic Intensity Pro 4k - and then only at 5.1?
Thanks to all!

Todd
 
M

___Maggi___

Member
Don't get me wrong, but why do you want to stream with 5.1 surround sound? Imho only a handful of users have a 5.1 surround system. It's like streaming in 4k. Some could do it, but nobody can watch it in this quality (unless they have a 4k Monitor of course).
 
T

TO4DM4N

New Member
Sorry, should have been more clear in my post. I’m looking to record in surround sound, minimal streaming and when I do it would be in stereo.
 
Boildown

Boildown

Active Member
I don't have a Magewell or a Blackmagic, but generally speaking it'll work with OBS if its done in DirectShow, it won't if it isn't. The other possibility is someone writes a plugin for a particular vender's SDK/API.

What I do is send my audio separately via a sound card's inputs in my encoding PC (Sound Blaster X-Fi). I haven't attempted to record surround on it though, but it seems like I probably could, as it has an optical input that is capable of it.
 
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TO4DM4N

New Member
Thanks, Boildown. I was thinking the same thing, that if I run optical into a pc sound card I should be able to pull the audio off that and use the sound card as an input recording device in OBS.

I also received a comment back from Magewell confirming that it does not support surround sound in DirectShow. They suggest using their SDK/API which is fine, but that doesn't help in using OBS at this time. As you mention, someone would need to write the plugin...well beyond my capabilities or capacity.
 
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Bensam123

Member
Running into the same problem right now. I own a Magewell HDMI Pro 4k Plus and it does support a LOT of different formats, the problem seems to be getting it out of the capture card. I've figured out how to force LPCM of up to 7.1 from the sending computer and in the audio signal status on the receiving PC it's showing all 8 channels connected, however it's unable to actually produce audio from more then two channels. So the card is receiving the channels correctly it just seems as though it's not doing anything with them.

On the receiving PC looking under sound settings > recording > audio device > advanced it only allows up to 2 channels to be configured, so it seems as though Magewell isn't properly supporting it in their drivers. I've not figured out a way to force more then 2 channels on the Magewell drivers.

A work around would indeed be a digital input/output setup, but if I can get the card to work like it's supposed to that would be nice. If anyone knows a workaround for encoding digital streams to send over HDMI from PC to PC I would be interested in that. All the guides I've looked at are pretty convoluted and a bunch of band aids on top of each other.


As a side note I've been waiting for OBS to add surround sound support for years.
 
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Bensam123

Member
Edit to the above, I also talked to Magewell support and they confirm that 'Windows doesn't support surround sound', but the card does, so they're basically just passing the ball on that one to whoever wants to work with the API and make a custom plugin for LPCM surround sound support.

Attempting to find a sound card that supports surround sound input is very... very... difficult. I have a old X-Fi card that does, but it's PCI, new stuff unless I want to plop down $150 doesn't really exist. You can find cards USB or PCI-E that support optical input, but that's just for a PCM connection and it doesn't support surround for multi-channels. They often times wont tell you whether or not it supports a surround sound input unless you do digging or contact their support.

Does anyone know of a capture card that supports digital optical or coaxial input for surround sound? That essentially would do the same thing.
 
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Harold

Harold

Active Member
The blackmagic Decklink cards may offer what you want.
The decklink mini recorder supports up to 8 channels of audio on hdmi. You'd need to use the blackmagic device source type.
 
T

TO4DM4N

New Member
Bensam123, thanks for your input and confirmation of my issues. Misery (well maybe not that bad) loves company.

Anyway, I ordered the Blackmagic Intensity Pro 4k. I'll post my results, but based on other posts, I'm thinking that this will work. The reviews on this card have been mixed, which is why I went the Magewell route. I really like the performance of the Magewell cards, so I'm disappointed to have to find an alternative card.

I'll test a few other solutions - sound cards with optical in, multiple capture cards, etc and see if something falls into place.
 
Harold

Harold

Active Member
Both Intensity (pro 4k and shuttle) also have 8 channels over hdmi.
Definitely use the blackmagic source and not video capture device source.
 
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Bensam123

Member
I actually own a pro intensity 4k... I wonder if I could use it for LPCM 8 channel input over HDMI and then use the Magewell for video. Not exactly what I intended, but I have them on hand. I'll take a look at this some time soon.

As far as reviews go, the card worked perfectly till when I pulled it from my system. I thought the same thing when I ordered it, it worked fine. Not sure if people didn't set it up right or what. You just have to make sure you swap some things in the blackmagic software (such as HDMI source sometimes). It's pretty easy to figure out, just poke at the switches till you get what you want.

Harold can you personally confirm that surround sound works over it? Not that it just can do it. The Magewell cards can do it, but they don't have drivers to do it, which sorta defeats the purpose, but this is something that doesn't seem is very well developed in the capture world... yet.

Decklink mini is $150, a little pricey just to get a surround sound signal to my capture PC. I'm currently looking into other options including sound cards. Hopefully I can figure out a intermediary solution that isn't as expensive.

Other option that doesn't seem to be very well explored is Dolby Digital encoding over HDMI (or any of the other encoded formats). I haven't found a solution yet that would do this. Naturally receivers and TVs do it, but computers just passthrough DD information through the HDMI interface for the most part and don't do encoding. Some sound cards, like Creative, do DD encoding over optical, but that's a different interface type then something we already use for video and getting a optical input that supports it seems pretty rare.


Good to see there are other people venturing into this area. I thought I'd just be able to flip some switches and this would work, but has turned into a bigger ordeal. Definitely interested to try the pro 4k now that you guys think it works.
 
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Bensam123

Member
Update on this, the Intensity Pro 4k is showing up to 7.1 (8 channels) on the sending PC. On the receiving PC it does not show up as a recording device in sound settings in windows. There is a device for it, but that is the analogue input for the breakout pins and not the HDMI input.

I used to stream with this card and you can get HDMI stereo in OBS, however, OBS does not seem to recognize surround input from it. There is little in the way of tweaking in the OBS control panel as well. Turning on 5.1 output only shows 6 channels for the windows audio desktop and not for the capture card. The capture card only shows up as stereo.

Not sure how to fix that besides OBS fixing it on their end. I'm not sure how much testing Jim or the devs did with surround sound as well (especially with capture card input). I will be contacting Blackmagic and see if there might be something they're working on or can fix in a driver update. They may play the pass the ball card like Magewell did with this. So for now the Intensity Pro 4k seems to be a dead end even though it's once again supposed to work.
 
T

TO4DM4N

New Member
Bensam, thanks for testing and sharing your findings. I should receive the Intensity Pro 4K today...hopefully I'm not just packing it up and sending it back. I'm pretty sure Harold is correct that you need to add it as a blackmagic device or OBS will not pick up the full functionality of the card. Maybe that's the trick?
 
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Bensam123

Member
Nope, I added it as a video capture device. I added it as a blackmagic device and surround sound options are now showing up as multiple channels in the mixer. However when setting the sending computer as 5.1 and the BM properties as a 5.1 in OBS the channels do not seem to play properly. They seem messed up. It seems as though only front left, right, center, and LFE play, even though surround plays on send it doesn't on receive. It also seems as though it doesn't have the right number of channels in OBS either (5 instead of 6, one for LFE).

I tried listening to a practice cast and the sound came out all chirpy, garblie, and stuttery. Usually this means there is a bit-mismatch somewhere (16 bit to 24 or something, different sample rate), I tried tweaking the send computer, but it never fixed it. The front left, right, and center worked in their garblie state, as well as sub, surround left and right didn't come through at all.
 
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Bensam123

Member
No I didn't follow that guide, however it didn't change anything after looking at it. It seems as though there is some sort of issue either the BM device isn't reproducing the right channels, OBS isn't seeing the right channels, or it isn't transmitting the right channels (while not showing them properly on the meters). Surround channels are completely missing from both the meters and the stream when I play test tones from the sending computer.

To4 try playing around with yours before you send it back, it could be I don't have something tweaked right or my setup is slightly incompatible.

The chirping may have been caused by too low of a bitrate, I will test it again later, but the missing channels isn't something that can't be fixed on my end.

Suslik I'm not recording locally. I'm not sure of the technical details of that commit, but it looks like it relates to local codecs. I just live stream so host > BM > OBS > Twitch
 
Suslik V

Suslik V

Active Member
Commit affects any stage of the encoding. It is about bit-map for the speakers layout. I think, @Jim don't want to make standards by making OBS code more strict (for example by cutting off loose ends - 2.1, 4.0, 4.1, 5.1 and 7.1 with sides speakers). Anyway, the changes were made is just part of the fixes, it is new feature for OBS Studio and thus it has bugs. According to the log handling changes, there should be bugfix release soon (v21.1.0 or so). I recommend to keep OBS Studio up to date.
 
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Bensam123

Member
Yup, not something I expected to work right out of the gate. Since it is a niche feature I doubt it will garner much priority, but one can hope!

Some other testing. Obviously if your computer that's running OBS has a surround speaker setup it will transmit properly, IE 5.1 > OBS > 5.1 comes out of twitch.

With the Black Magic Pro Intensity 4k card I experimented a bit more and it seems sound is messed up in general. I was using it as a video capture device before and the sound only works properly when you set it up to output to desktop instead of through the stream. If you just try to output it through the stream it's all garblied up, it doesn't matter if it's stereo or surround. Using the Black Magic source it does the same thing, it's all garblie and you can't output it to desktop in the first place, only to stream. So something is messed up in the Black Magic plugin or I don't have something setup properly.

Would be nice if someone else can verify this with their own card.
 
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