23.0.78 (10/24/2017)
8. NEW: Keyboard shortcuts for video lipsync adjustment. SHIFT+COMMA (SHIFT+, or '<') to delay audio, SHIFT+PERIOD (SHIFT+. or '>') to advance audio, by 50 ms. SHIFT+SLASH (SHIFT+/ or '?') to reset to zero. This works for all DirectShow video file playback and time-shifted live TV. Not for live TV in non-time-shifting mode (as VideoClock is disabled in the mode).
I've had a bit more of a play with this.
I see it applies the change globally for the current Zone, as shown in the "Options > Video > Advanced > A/V sync correction milliseconds" for both the 24 Hz and the 50, 60, 120 Hz display settings.
The changes are therefore persistent across MC restarts, and can be different for different Zones. Which is good, because it means that the WDM Driver Zone can be adjusted on the fly for a source without affecting other Zones.
But I was sort of hoping for a file/stream/source specific adjustment, with that adjustment stored against the file or against the stream (source) when using the WDM Driver with an external source, so that any adjustment made is persistent, but only for that source. I realise that this could be problematic, as the source isn't in the MC library typically, when using an external source with the WDM Driver. If an adjustment could be stored again each "Connected Media" record under Video, that would work for me. Maybe Ctrl+< and Ctrl+> could be used to adjust the currently playing "Connected Media" source?
For example, if I am using the WDM Driver with catch up TV I could be using one of several sources, from various channels. They all use different technologies and all produce different amounts of lag through the WDM Driver. At the same time streaming sources such as Stan and Netflix would have a different lag, although I haven't tested that yet. So a base adjustment for the Zone, plus a source specific adjustment would give me the most flexibility and the least work.
I was also hoping for it to be done via the OSD menu, so that I can use my remote immediately and see the amount of adjustment, much like the subtitle timing adjustment. But of course there is no OSD for "Connected Media" sources, so a keyboard shortcut, or maybe just a property of the "Connected Media" record would have to be used instead.
File specific adjustments for files in the library would still make sense via an OSD menu, with the adjustment stored in the [Playback Info] tag. Does tha ability to adjust lipsync via a setting in this tag already exist? I've never seen anything about it if it does.
I find it easy to see when lipsync is out, but if it is close I find it hard to determine which way it needs to be adjusted, earlier or later, so it can be fiddly and time-consuming to get it right. Therefore it would be nice if it could be adjusted for a source just once, and left alone, while persisting between MC sessions.
Also, I thought the 50ms steps was going to be a problem, but that seems to be okay.
So in summary:
An OSD for file specific lipsync adjustments, stored in the [Playback Info] tag. Useful when specific recordings or files have lipsync problems that need fixing, and an adjustment is preferable to editing the file.
The Keyboard Shortcuts < and > adjust the lipsync for a Zone, for all display settings, as per this new functionality.
The Keyboard Shortcuts Ctrl+< and Ctrl+> adjust the lipsync for a specific source in the "Connected Media" section, and programs in addition to web site can be added to "Connected Media", so that for example a Netflix App can be adjusted.
That is asking a lot, isn't it? Well, can't hurt to ask. Plus I'm sure that there are better ways to handle all sources. But maybe asking will prompt some thought.