Audio/Video sync adjustment

We notice when playing some videos and recorded TV shows on Windows Media Center that the audio is out of sync with the video. I seem to recall that MPC-HC has some key strokes that can adjust the lag to advance or retard the audio to get it in sync with lip movement of the characters.

Can someone advise me on a step-by-step method of getting the video and audio in sync, please? I believe the increments of adjustment are very small, so I'm wondering how many keystrokes would it take to advance or retard the audio by, say, one sixteenth of a second, or one-eighth of a second, or one-quarter of a second. Sometimes I can tell they're not in sync, yet I'm not sure if the audio is behind or ahead; therefore, a sizable jump ahead or back would make it more obvious which way it needs adjusting. Hope this makes sense. So, can you tell me exactly how to advance or retard the sound in those increments, please?

You can't adjust delay with a keyboard shortcut in Windows Media Center. But you can find a delay option in LAV Audio Decoder, which you can set to a specific value. If WMC doesn't use LAV Audio Decoder, then you need to disable Microsoft's audio decoder with the Codec Tweak Tool.

In MPC-HC you can adjust delay with the Plus/Minus keys on the numeric keypad. It does steps of 10 ms.

What is the CPU usage during playback? Audio sync issue could be due to a performance issue.

This may help:
Windows Media Player > Options > Performance > Drop frames to keep audio and video synchronized

Admin wrote:You can't adjust delay with a keyboard shortcut in Windows Media Center. But you can find a delay option in LAV Audio Decoder, which you can set to a specific value. If WMC doesn't use LAV Audio Decoder, then you need to disable Microsoft's audio decoder with the Codec Tweak Tool.

In MPC-HC you can adjust delay with the Plus/Minus keys on the numeric keypad. It does steps of 10 ms.

What is the CPU usage during playback? Audio sync issue could be due to a performance issue.

This may help:
Windows Media Player > Options > Performance > Drop frames to keep audio and video synchronized

Thanks for your reply. Regarding each of your points:

It's interesting that Windows Media Center can be modified to use a different audio codec. I'm reluctant to do that, however, in view of the fact that we don't want to risk messing up our current and only means of recording and viewing TV shows. We could, in theory, create a System Image backup, then try the suggested codec replacement. Unfortunately, some recordings made after the backup date may become unplayable following a Restore (or maybe it's the other way around). Anyway, that happened once before and we don't want to endure that again).

We already know about MPC-HC adjust audio delay. In my experience the plus/minus keys did nothing. It was necessary to actually create / designate a keystroke combination to facilitate the adjustment. In MPC / Options / Hotkeys the under adjust audio it says "Add", meaning you should double-click on "Add" then choose a keystroke combination.

My question was how to adjust by more than 10ms at a time. Does one simply tap the designated keystroke(s) multiple times whilst counting 10, 20, 30? Or, what?

Will check the cpu usage wduring playback and try the Windows Media Player drop frames adjustment, but I don't think that's the problem. Our cpu is an Intel Core i5-4590 @ 3.3GHz. Idle cpu usage is around 2% to 4% so the cpu always has plenty of headroom during media playback .... but I'll check anyway.

Any adjustments that you make with the Codec Tweak Tool can easily be reverted. No need for backups or restore points.

The default keycombos work fine here. The numeric keypad is on the right side of your keyboard. The plus/minus to the left of the backspace button are different keys.

Yes, a 100ms delay would mean pressing 10 times. You can also set a value directly in: Options > Internal Filters > Audio Switcher

This sometimes helps to fix audio problems:
Windows Control Panel > Sound > Speakers > Properties > Advanced > disable the two "exclusive mode" options

Quick update. Checked cpu and memory usage during Windows Media Center playback of recorded TV shows and live TV as well. CPU usage never exceeds 26% even with Chrome browser open in background with 8 tabs active. Memory usage never exceeds 30%; thus, neither of those parameters would seem to be involved with audio/video sync problems.
Will try other suggestions and report back over next few days.