Out of Sync audio converting videos

[iboz1802]

Hey everyone, everything was fine up until last week.
I'm not new at OBS for converting old videos to MP4, however, as of last week, every single video I digitize has out of sync sound.
I've tried VCR, Camcorders etc... I even tried other types of USB capture cards. Same problem.
Is this a software issue? does anyone have a solution?
Google says to go into audio settings and mess with the delay but why? this is happening on all 6 of my computers.
Any genius' out there? is it because im converting to MP4 instead of MKV?

 

[Suslik V]

...is it because im converting to MP4 instead of MKV?

Surely not.

Old tapes may has no synchronization. Capture card may not support input format.

Device drivers, digital clocks accuracy, and capture process performance are all important for synchronization. You may feel frustrated, but the general rules for long-running workstations are: "Don't touch anything", "No updates", "Patience".

 

[iboz1802]

Surely not.

Old tapes may has no synchronization. Capture card may not support input format.

Device drivers, digital clocks accuracy, and capture process performance are all important for synchronization. You may feel frustrated, but the general rules for long-running workstations are: "Don't touch anything", "No updates", "Patience".

thank you. But how weird is it that all of my computers have the same audio delay. Either it's a VHS or a MiniDV, the problem persists even on different computers. Is there a solution?

 

[Suslik V]

Each de-synchronization case has its own causes.

For example,

1. If the source's audio was recorded delayed in the original tape, how do you fix this? In the editor!
2. If the source's audio is delayed because samples were missing (CPU overload), how do you fix this? By reducing complexity of the encoding!
3. If the source's audio is delayed because samples were converted from incompatible sample rates, how do you fix this? Configure your devices to use one sample rate! FPS is also kind of sample rate...
4. If the source's audio is delayed because the device has terrible clocks, how do you fix this? Replace the capture device (you may use other device, like "Line-in" jack of the PC to capture the audio, instead of relying on the capture card digitization)!

and so on.

 

[Lawrence_SoCal]

All computers having same issue? I'd start with security software, group policy settings, or similar...
Are you using same USB hub/capture device interface? could easily be device driver related

Assuming audio/video in-sync in source, then getting out of sync is usually due to a bottleneck slowing one data path (audio or video) down, and not the other. Troubleshooting would involve
1. making sure now CPU bottleneck... that includes background running processes that changed how it interacts with audio sub-system and Operating System was ok before, and now isn't?
2. then no recent BIOS firmware, security software, or similar causing PCIe, chipset, or similar oddities (reference both AMD and Intel issues in recent years)

basically, what do you have in common across all of your computers? and no make sure some of that is NOT in common (ie, change it and test results)...