OBS Multi-Channel Audio Support

[EnterNoEscape]

I was wondering how the OBS project was coming along and I found a really useful commit. Someone has added multi-channel audio support and even more generously posted a compiled version you can try before the next OBS release with support.

I set up a spare computer with WMC, set the audio to 5.1 using the digital output of my sound card (I don't have anything actually connected to it). I then configured the software to use 5.1 channel audio and Custom output so I could stream over my LAN using UDP. Sure enough I was streaming HBO WMC live playback using H.264 (1280x720), AC3 (5.1) in an MPEG-TS container over UDP.

I want to test this a little more, but if this really works that well, I plan to add direct support for MPEG-TS over UDP to OpenDCT so you don't need to using Generic Pipe and FFmpeg similarly to how people are using it for webcams.

I just wanted to share my exciting findings and if this intrigues enough people, I can post a how-to so you can try it out yourself.

[trk2]

I'm intrigued.

[EnterNoEscape]

Originally Posted by trk2

I'm intrigued.

I guess that's enough people. It's not too hard and OBS even has a mode that can capture the WMC playback without it even being the foreground window; meaning you might be able to use the computer for other things. The only downside at the moment is that you would need to leave capture on 24/7 because I don't have a mechanism at the moment to turn it off when you're not streaming, but I have a feeling that's not going to be very hard given how flexible OBS is. I'll try to get something up this evening.

[trk2]

This sounds awesome. I'm already using your WMC Live TV Tuner setup with an extender to capture premium channels. This would greatly simplify the whole setup and get me 5.1 audio. Do you think it would be possible to run multiple instances of WMC in VMs for additional tuners? If so, I may upgrade to the new 6 tuner HDHR Prime...

[wayner]

What is OBS and does this just apply to CableCARD tuners?

[UgaData]

I am also interested. Where can an overview of what OBS is be found?

I did find this might help with starting and stopping an OBS stream.


EDIT: OBS - Open Broadcaster Software.

[wayner]

Originally Posted by UgaData

EDIT: OBS - Open Broadcaster Software.

Where it says:

Free and open source software for video recording and live streaming.
Download and start streaming quickly and easily on Windows, Mac or Linux.

But I still don't know what that means. Does this give functionality that VLC does and which (I think) is still used by some to stream SageTV content remotely? Does OBS allow you to capture and stream content that has DRM, like Netflix. Could you use this to stream "PC content" like Netflix into something like SageTV? Would this replace ffmpeg for things like SageTV Placeshifter to allow Placeshifter to work properly with 1080i content, and maybe even higher rez content like 2160p?

[Telecore]

I am interested - I have both a SageTV and a WMC Server and could test this.

[UgaData]

Link to the OBS PDF

The impression I am getting so far this is a tool for video podcasters, it can grab video from various sources on a computer, manipulate it and then stream it.

[KryptoNyte]

Definitely interested

[EnterNoEscape]

Originally Posted by trk2

This sounds awesome. I'm already using your WMC Live TV Tuner setup with an extender to capture premium channels. This would greatly simplify the whole setup and get me 5.1 audio. Do you think it would be possible to run multiple instances of WMC in VMs for additional tuners? If so, I may upgrade to the new 6 tuner HDHR Prime...

I've tried things like this, but haven't had much success. You can technically run multiple instance between different user profiles, but you would then need a sound card for each one or they will mix their audio. There are some virtual sound cards that could fill this need, but it starts to get really complicated. Also, I think I remember having some DRM related problems with this approach.

[EnterNoEscape]

First, we want to set up and test streaming from OBS to a player that can deal with UDP broadcast. I will be using VLC. The WMC computer is Windows 7. I don't know if this works on other OS's.

1. Download and install OBS multi-channel beta on the computer you have Windows Media Center installed on using OBS-Studio-MC-20.1.3c-win-x64.exe from here. The defaults are fine.

   If you have another version of OBS installed, I recommend uninstalling it first or the shortcuts get weird. Like-wise when multi-channel support is added to the mainstream distribution, you'll want to uninstall this beta before installing the normal version of OBS.

2. If you accepted the defaults, OBS 20.1.3-104-gf08569f-modified should open after the install.

   If it doesn't you can find it on the Start Menu by searching for OBS. If it's not on the Start Menu, you'll have to navigate to C:\Program Files (x86)\obs-studio-MC\bin\64bit and run obs64.exe.

3. Click No to the auto-configuration dialog if you see it. Then OK.
4. Open Windows Media Center (WMC). You do not need to start live playback at this time. We just need the application open.
5. Switch back to OBS.
6. Click on the + (Add) under Sources in the lower left.
7. Select Game Capture
8. Make sure Make source visible is checked. Click OK.
9. Next to Mode, select Capture specific window from the dropdown.
10. Next to Window, select ehshell.exe from the dropdown.
11. Next to Window Match Priority, select Match title, otherwise find window of same executable from the dropdown.
12. Uncheck Multi-adapter Compatibility.
13. Check Force Scaling. Set Scale Resolution to 1280x720.
14. Uncheck Allow Transparency.
15. Uncheck Limit capture framerate.
16. Uncheck Capture Cursor.
17. Click OK.
18. You should now see WMC without window borders inside of OBS even though OBS is in the foreground.
19. Click Settings in the lower left.
20. Click on the Output tab.
21. Next to Output Mode, select Advanced from the dropdown.
22. Click on the Recording tab.
23. Change Type to Custom Output (FFmpeg)
24. Change FFmpeg Output Type to Output to URL
25. Enter UDP://<player_ip>:<port> in the File path or URL text box. (e.g. If the computer you want to stream to has the IP address 192.168.1.2 and you want to use port 60001, you would enter: UDP://192.168.1.2:60001)
26. Change Container Format to mpegts
27. Check Show all codecs
28. Change Video Encoder to libx264
29. Change Audio Bitrate to 480
30. Change Audio Encoder to ac3
31. Click on the Video tab.
32. Change the Base (Canvas) Resolution to 1280x720.
33. Change the dropdown next to Common FPS Values to 60.
34. Click OK
35. Click Start Recording (not Start Streaming)
36. Start live playback on WMC.
37. Open VLC on the computer you are streaming to.
38. Open a network stream and use the port you chose like this udp://@:<port> (e.g. udp://@:60001)
39. You should now be streaming WMC with stereo audio.
40. You can stop recording at any time by clicking Stop Recording on OBS.

    There are some color washed out issues to be dealt with, but this should give you an idea of if this will work for you or not.
    

To enable multi-channel audio, first you need to configure your default playback device to 5.1. In my case, I got very crappy sound using the 5.1 analog output. I had to use the digital output set to 5.1 for the sound to be good. If you change the default playback device, you will need to re-open WMC and OBS.

1. Open WMC if it isn't open already.
2. Open OBS if it isn't open already.
3. Click Settings in the lower right.
4. Click the Audio tab
5. Change Channels to 5.1.
6. Click Yes to the warning.
7. Click OK.
8. Re-open OBS.
9. Start live playback on WMC.
10. Switch back to OBS.
11. Click Start Recording (not Start Streaming)
12. Open VLC on the computer you are streaming to.
13. Open a network stream and use the port you chose like this udp://@:<port> (e.g. udp://@:60001)
14. You should now be streaming WMC with 5.1 audio.

This is as far as I've gone. My time is very limited and this took at least an hour to write up. I hope to post more soon. It doesn't take too much imagination to see how you can use ffmpeg.exe to feed a stream like this into OpenDCT.

[trk2]

I was able to trial this and somewhat verify it worked. For some reason I wasn't able to get any sound while streaming, but it did record in 5.1 if I recorded instead to file. My server struggled to keep up with the encode, so that may be the issue.

Also OBS will throw an unspecified error if "UDP" in the UDP address is in capitals. So use udp://192.168.1.2:60001 instead of UDP://192.168.1.2:60001.

[EnterNoEscape]

Ok. After playing around a bit more, I realized that it's not hard to get a copy of nginx compiled for Windows with RTMP support and I followed this tutorial. The bonus is that I can now use QuickSync, so that makes me a lot happier. I would still prefer the webserver to output RTP or HTTP, but this is closer to what OBS does best and you only need one nginx server because you can just point all of your other WMC computers to that same server with different streaming keys. I suspect I can get something working nicely out of this arrangement.