Facecam video and microphone audio lose sync during livestream and recording. Any idea?

[aristotelis27]

Hello guys,

I have been suffering from an issue, which I have no idea why it keeps on happening. Whether streaming or recording using OBS, after a random amount of time the microphone is not synced with the camera and the bad thing is that it keeps getting worse and worse as the time goes by. Every time I start my stream, sound/webcam are always synced, but after let's say 30-35 minutes, synchronization is completely lost and the main problem is that there is not a fixed amount of time that is lost. It might start with 300ms, go up to 700 ms and also more than 1sec. I am so frustrated because I can not have this thing in my mind all the time, while streaming or recording and I do not understand the reason behind it. Yeah, I can fix it temporarily with an additional delay on my microphone, but that is not a viable solution anymore...

I thought it was due to the x264 encoder which was using up to 25-30% of my CPU, so I gave it a go with the Apple H264 VT Hardware Encoder which is using less than 10% of the CPU, but the problem is still there if not worse... Bitrate for streaming is set to 4000 Kbps and for recording at around 8000 Kbps. I am 100% sure (hope at least) that this is not because of my computer specs, as the iMac I built is one of the most stacked versions from the 2019 release.

I know that OBS works better with Windows, but I tried many times installing Bootcamp on my Mac. It works great but I can not make my damn Elgato HD60S get recognized (stupid USB 3.0 error), but that is another story that even Elgato themselves did not help me resolve. Just wanted to let you know I tried the bootcamp solution but have extra limitations there... I know I could run Elgato Capture software to stream, but it does not offer the customization OBS does.

Setup elements (H&S):
1) Webcam (Logitech StreamCam)
2) Microphone (RODE NT-USB)
3) Game Capture (Elgato HD60S) which is utilized via NDI plugin in OBS and the official OBS-Link software of Elgato
4) Desktop audio capture via iShowU Audio Capture

Does anybody have any idea or have encountered the exact same problem and would like to propose a solution? If there is a hint for you in the log file, let me know if you would like to look into it.

Cheers and I really hope someone can help me resolve this...

My iMac's specs can be found below:
iMac 5K 27-inch 2019
3,6GHz 8-core Intel Core i9
24GB RAM
Radeon Pro 580X 8GB

 

[ShadowBark]

Howdy! My name is James and I work with audio in the film industry. This is a very common issue. Usually, it has to do with the framerate of your camera! Audio actually doesn't playback through TRUE 24, 30, and 60fps. Audio actually plays back ever so slightly slower than true framerates. With this being said, in longer recordings, audio will begin to un-sync because they are not playing back at the same speed. This is an easy fix though!

Depending on your webcam, use one of the following framerates.

23.98fps instead of 24
29.978fps instead of 30
59.94fps instead of 60

These are the framerates that movies, professional video, and documentary films are shot in. This should hopefully fix your issue! Please let me know if this helps, or if you have any more questions!

 

[aristotelis27]

Howdy! My name is James and I work with audio in the film industry. This is a very common issue. Usually, it has to do with the framerate of your camera! Audio actually doesn't playback through TRUE 24, 30, and 60fps. Audio actually plays back ever so slightly slower than true framerates. With this being said, in longer recordings, audio will begin to un-sync because they are not playing back at the same speed. This is an easy fix though!

Depending on your webcam, use one of the following framerates.

23.98fps instead of 24
29.978fps instead of 30
59.94fps instead of 60

These are the framerates that movies, professional video, and documentary films are shot in. This should hopefully fix your issue! Please let me know if this helps, or if you have any more questions!

Hello mate,

Thank you for proposing this adjustment in the frame rate, I will give it a go in my next stream tomorrow and will get back to you for confirmation.

Just to be sure, you are talking about changing the Common FPS values in the ”Video” tab, right under Base Canvas Resolution and Output Resolution, right? I used to go with 60fps so I will switch it to 59.94 for my next stream.

 

[ShadowBark]

Hello mate,

Thank you for proposing this adjustment in the frame rate, I will give it a go in my next stream tomorrow and will get back to you for confirmation.

Just to be sure, you are talking about changing the Common FPS values in the ”Video” tab, right under Base Canvas Resolution and Output Resolution, right? I used to go with 60fps so I will switch it to 59.94 for my next stream.

Yes, I wouldn’t use true 60 for anything. Anything that is set to 60, change to 59.94 if possible. This should fix your issue. Look forward to hearing about your stream!