Bug Report The filter Video Delay (Async) works on display, not on output

B

Barabba

Member
Hi, I've a big problem here, I've an udp audio stream source, and 3 cams connected by rtsp. Of course there are differences of syncronizations between streams, so I used the filter to delay enough the videos to have the result. Looking on the OBS window all seems perfect now, all cameras looking the same scene are syncronized and audio tto, but the output stream is out of sync, it looks the filter is ignored for the encoding, how this is possible?
I think that exactly the image I see in OBS window is encoded yes? So how can I have a different result?
Are filters only "preview" and I need to apply the to the encoder? Strange..
 
OBS audio monitoring does not apply sync settings -- this is only for the output recording. Your video (async) delay filters do apply directly to your preview though.

The only true indication you will have of audio to video sync is via an output recording.
 
Thanks for answer, I think I didn't understand 100% and I would to be sure, so:
- does not apply sync settings = I can't configure delay on audio, only video.
- this is only for the output recording = it means it's not for preview.. but I'm getting confused now, so you mean what I'm seeing is not what it will be encoded? It's strange.. I suppose the encoder is just encoding the preview.. it has more logic and it makes me sure about result. Can you explain more how OBS then works?
- The only true indication is via an output recording = means I can't believe the preview, why? (connected to the previous question)

Well I figure out what happened to me, I can't talk now about preview because I'm not at th place (I'm remotely managing now), but downloading records I figured out the desyncronization, that it disappear only when the program is restarted and new record is done. There is a bug so.. that OBS forgets to apply the set delays for some reasons, and I think the reason is I used Anyview to see vide and hear audio, there is probably a conflict occuring, or a high priority cpu usage from Anyview that creates problems. I'm using Win7-64. Usually I'm connected with tightvnc which is much slower and doesn't have audio.. but it doesn't affect OBS.
 
I'm looking more deep on the problem, it looks that time passing affect the syncronizations, the streams start to delay each other and there is nothing to do to keep them syncronized. I don't know if it is a bug of OBS managing the buffers for every RTSP decode..
 
it's really hard to get RTSP cameras in sync, in different times I can open OBS I can have a different delay. There is no way to improve this? You may say "no beacuse it depends on VLAN". Maybe can you use the clock numbers of the camera (seconds, when they change) to have a kind of syncronization?
 
Hello,

I think we have the same problem like you.
We want to build a sreaming system in our church with 3 cameras. We have ptz ip cameras with rtsp stream, an analog audio mixer and we wanted to use the OBS program for streaming, but we noticed that the videos from the cameras are in delay, compared to each other, and also compared to the audio from the analog audio mixer.
In the OBS we can adjust the audio and also the video delay parameters, but we noticed that each time we restart the OBS, the 3 video feeds and the audio feed are delayed in a random way, so the previously adjusted delay compensation parameters are not covering the actual delay situation.
The builders of the system said that maybe using vMix instead of OBS will solve the problem.
Did you managed to solve it somehow with OBS or other program?

Thank you in advance!
Zoltán
 
Barabba said:
it's really hard to get RTSP cameras in sync, in different times I can open OBS I can have a different delay. There is no way to improve this? You may say "no beacuse it depends on VLAN". Maybe can you use the clock numbers of the camera (seconds, when they change) to have a kind of syncronization?
Click to expand...

Camera sync is a real issue. Production studios used to run timecode to every camera so they were synced to the same frame clock. These days every camera is on its own, and they don't run at precisely the same speed, so they drift apart. One thing you can try is set them to stop when not visible. They should resync when you return to the shot. Some cameras don't like that, though.
 
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