MartinInCO
New Member
I'm recording video from a USB webcam and audio from a separate USB microphone and when I play back the video they are out of sync a little bit. Is there a way to fix this? Thanks!
Audio and Video not synchronized
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Lawrence_SoCal
Active Member
Is there an *automatic* way? not that I'm aware of. cyclemat indicated the usual method, which is to add a delay on the Audio input in the OBS Audio mixer
There are numerous pre-made videos with an audio track that help fine tune the sync, manually. I personally used the MP4 video from Ballast Media. ..there are plenty of others.
How the videos typically work - The idea is to point your camera & mic to a device (tablet, phone, laptop, TV, whatever, ??) playing the specially crafted video. record that in OBS. During playback you can then listen/watch, and get a better idea of the delay (usually in audio) required to achieve a sync. In the Ballast Media video you listen and stop/freeze video during playback and the bouncing ball in the video indicates how far off, in milliseconds the audio is from the video... easy peasy [but ymmv, so make adjustment in OBS with Audio delay, then retest]
Why this happens? the audio and video signals travel different paths, and the audio, being MUCH smaller in bandwidth, usually gets processed faster
There are numerous pre-made videos with an audio track that help fine tune the sync, manually. I personally used the MP4 video from Ballast Media. ..there are plenty of others.
How the videos typically work - The idea is to point your camera & mic to a device (tablet, phone, laptop, TV, whatever, ??) playing the specially crafted video. record that in OBS. During playback you can then listen/watch, and get a better idea of the delay (usually in audio) required to achieve a sync. In the Ballast Media video you listen and stop/freeze video during playback and the bouncing ball in the video indicates how far off, in milliseconds the audio is from the video... easy peasy [but ymmv, so make adjustment in OBS with Audio delay, then retest]
Why this happens? the audio and video signals travel different paths, and the audio, being MUCH smaller in bandwidth, usually gets processed faster
MartinInCO
New Member
Lawrence_SoCa thanks for so much detail. This will help tons!!! Thanks to you too cyclemat.
BTW: This is not an "OBS problem" This is a typical problem when video comes from one
place and audio comes from another. They are not being locked together by a source.
The automatic way do improve this is to use a video camera with audio inputs and run
the audio through the camera, so the video and audio arrive and are processed together.
I highly recommend that. Of course, once you need to perhaps mix multiple audio sources
in a mixer, you are back to the scenario where the audio is then following a different path from the video and the the mixed audio will usually have to be delayed to match the video.
place and audio comes from another. They are not being locked together by a source.
The automatic way do improve this is to use a video camera with audio inputs and run
the audio through the camera, so the video and audio arrive and are processed together.
I highly recommend that. Of course, once you need to perhaps mix multiple audio sources
in a mixer, you are back to the scenario where the audio is then following a different path from the video and the the mixed audio will usually have to be delayed to match the video.
St Philip Lutheran
New Member
We are streaming contemporary worship with a PTZ video camera (no audio) and a Presonus USB mixer. A few months back, we used a Presonus AudioBox USB audio interface, set the audio delay to 115 ms and we were 'good to go', In the meantime (several OBS releases and a new computer), we switched to ASIO (return borrowed USB audio interface), set the audio delay to 30 ms and it all appeared to 'good to go'. Then an audio consultant strongly urged us to get a new AudioBox 96 USB interface so we could get more audio range. We did and now no matter what I set the audio delay to -950ms->+950ms or in between the audio-video sync mismatch is unchanged (sounds like ~500 ms) and bad. Has anyone noticed an OBS change?
I had the same problem with video and audio from a single camera starting out synchronized but getting out of sync after awhile. I could fix it by periodically stopping and restarting the camera input stream, but it was tedious doing this manually. I found a way to automate the process using the AutoHotKey app running under Windows, described at https://ataridogdaze.com/tech/obs-auto-refresh-input.html
Lawrence_SoCal
Active Member
Couple of things
1. As a fellow HoW using a Presonus mixer (AR12 USB in our case), I would really like to learn more of your setup
2. A new computer will most likely have a significant impact on processing power, and therefore required delay to sync audio and video. In our case, use analog stereo sub-out on mixer to OBS PC (i7-10700K) along with a single Panasonic 1080 NDI PTZ camera, our audio sync is good enough that I'm not using any delay at all.
In your case, have you used a test sync video like streamgeeks.us (PTZOptics) provides for free? I've used https://streamgeeks.us/fix-audio-sync-issue-in-obs/ downloaded onto a tablet, then point camera and a mic at tablet, play video, and oila
Now, if the sync is varying, that is a whole other issue (usually CPU overload or more likely a driver problem)