Question / Help Streaming video to local TV's...?

joelgraff

New Member
So I'm trying to use OBS to provide video to TV's located in the same building, connected using HDMI-over-ethernet units. Thus far, I've had reasonable success simply putting OBS in projector mode and passing through the audio.

However, we recently networked our video camera over RTSP and latency suddenly became a much larger problem - on the order of 2 seconds. I'm trying to sort that out, as there's no good reason it ought to be that bad, but it put the issue of being able to add latency to the audio front and center.

From what I can tell, there's no way to get that done in OBS when simply using projector mode... The only other thought I had would be to try to set up a fake stream from OBS to take advantage of the 'Sync offset' option in the audio source preferences.

Any ideas how I can handle audio syncing when I'm not streaming to the internet?
 

Narcogen

Active Member
There isn't really a good way to do this because OBS isn't made for this kind of application.

As you're noticing, audio monitoring in OBS is *input* monitoring. You don't get the same output timed the same way as you would as outputting a stream. OBS considers the projector to be a confidence monitor, not an output.

The problem is that OBS doesn't consider an HDMI output to be a 1st class output target, the way it does an RTMP stream or an FFMpeg session. Other software does, but not OBS. You can use OBS for this if you set up an NGINX/RTMP server to output to from OBS, but that means your clients can't just be TVs with HDMI ports connected to adapters, they need to be client devices that have RTMP capable players or web browsers in them.
 

joelgraff

New Member
Hmm. I'm also dealing with really long latency - something on the order of 2 seconds. I get the impression that OBS isn't great at RTSP...

So I'm kicking around various options. For example:

1. Run the mixer line out to the camera so it's all encoded at the source. Adding more cameras in the future may prove problematic, though. Plus, it's a 50' run from the mixer to the camera - not crazy about that idea.
2. Embed the audio on a converted HDMI signal at the mixer, then hand it off to OBS using a capture card. Problem is, capture cards are a bit pricey.
3. Use VLC to handle the RTSP... maybe mix the audio in at that point and feed it into OBS? Don't know anything about that, but I read somewhere that VLC seems to do well with RTSP. Well, 60 ms beats 2000+, anyway.
4. Shell out $60 for vMix... assuming it's able to treat HDMI as a first class target. Not my preferred option, to be sure.

edit: #5 - Maybe output to a multicast address via UDP as suggested here? That would still allow me to output HDMI locally and stream...
https://obsproject.com/forum/resources/obs-studio-send-an-udp-stream-to-a-second-pc-using-obs.455/
 
Last edited:

Dihelson

Member
So I'm trying to use OBS to provide video to TV's located in the same building, connected using HDMI-over-ethernet units. Thus far, I've had reasonable success simply putting OBS in projector mode and passing through the audio.

However, we recently networked our video camera over RTSP and latency suddenly became a much larger problem - on the order of 2 seconds. I'm trying to sort that out, as there's no good reason it ought to be that bad, but it put the issue of being able to add latency to the audio front and center.

From what I can tell, there's no way to get that done in OBS when simply using projector mode... The only other thought I had would be to try to set up a fake stream from OBS to take advantage of the 'Sync offset' option in the audio source preferences.

Any ideas how I can handle audio syncing when I'm not streaming to the internet?

Your setup looks so complex... Here in my home, I have 5 TV's connected through HDMI receiving the signal from one computer, broadcasting from OBS, and on this computer, all kinds of sources. No latency problems. I just use a good HDMI splitter and send the signal through HDMI to any distance. If you just need to send the signal through HDMI, even for an entire building, what's the problem using splitters ?
 

Narcogen

Active Member
OBS is not a particularly good RTSP client. It's not intended for that at all. VLC as a client and capturing that in OBS works better.
 

scaesare

New Member
Hmm. I'm also dealing with really long latency - something on the order of 2 seconds. I get the impression that OBS isn't great at RTSP...

So I'm kicking around various options. For example:

1. Run the mixer line out to the camera so it's all encoded at the source. Adding more cameras in the future may prove problematic, though. Plus, it's a 50' run from the mixer to the camera - not crazy about that idea.
2. Embed the audio on a converted HDMI signal at the mixer, then hand it off to OBS using a capture card. Problem is, capture cards are a bit pricey.
3. Use VLC to handle the RTSP... maybe mix the audio in at that point and feed it into OBS? Don't know anything about that, but I read somewhere that VLC seems to do well with RTSP. Well, 60 ms beats 2000+, anyway.
4. Shell out $60 for vMix... assuming it's able to treat HDMI as a first class target. Not my preferred option, to be sure.

edit: #5 - Maybe output to a multicast address via UDP as suggested here? That would still allow me to output HDMI locally and stream...
https://obsproject.com/forum/resources/obs-studio-send-an-udp-stream-to-a-second-pc-using-obs.455/

For the mixer audio input I'm capturing, I add ~1250ms audio delay within OBX to sync to my RTSP cam stream.

Click the gear icon for that channel in the mixer dock, go to Advanced Audio Properties, and add Audio Offset delay.
 

Sam Hones

New Member
So I'm trying to use OBS to provide video to TV's located in the same building, connected using HDMI-over-ethernet units. Thus far, I've had reasonable success simply putting OBS in projector mode and passing through the audio.

However, we recently networked our video camera over RTSP and latency suddenly became a much larger problem - on the order of 2 seconds. I'm trying to sort that out, as there's no good reason it ought to be that bad, but it put the issue of being able to add latency to the audio front and center.

From what I can tell, there's no way to get that done in OBS when simply using projector mode... The only other thought I had would be to try to set up a fake stream from OBS to take advantage of the 'Sync offset' option in the audio source preferences.

Any ideas how I can handle audio syncing when I'm not streaming to the internet?
Rtsp: at a church we have a PTZ IP CCTV camera and rtsp into OBS is very unpredictable, though the camera viewing software, running still under IE is very stable and window capture that is stable in OBS. We also use Manycam which will take the rtps and make it available as webcam, NDI source which will also happily go into OBS.
As far as lag is concerned in our case 535ms which we adjust to in advanced sound settings. As we also run virtual cables all input is monitored on cable A then output through mic/aux3. In order to not have to mess with the sound, sources without lag have renderdelay filter added to bring it up to the camera's lag and then all syncs.
 
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