[frarev]

Remember: That setting makes only sense, if it is combined with Adjust Refreshrate to match video. It's quite stupid to Sync Playback to Display, when content has 24 or 23.9758 fps and Display is running at 60hz.

Edit:
Perhaps something to add. Passthrough sucks from a sync point of view :-) If video is not encoded properly, e.g. some frames missing from time to time, wrongly converted, so that video and audio slowly get out of sync, the only chance with passthrough is to "drop" or "duplicate" packages. Those packages are mostly of 32ms time and those are "raw" packages, just a bunch of data xbmc does not touch at all.

Syncing decoded streams e.g. dts or truehd or ac3 as lpcm (this conversion is lossless(!)) is much easier, as you can do a little bit of resampling to speed up or speed down without sacrificing the sync.Sadly there is no OSS DTS-HD Master audio decoder yet and the DTS-Core is used instead.

Out of that reason some people choose "Audio Clock" for sync. There we can skip, drop, resync video output which might give "visual stutter" but not audio artifacts.

yesterday night I tried to watch 2 movie-show with, off course, the Adjust Refreshrate to match video ON, and the Sync Playback to Display ON (I never used this option before) with drop/dupe Sound option : it's true that I had NO stuterring ; usually, I always had few and smal stuttering while watching (I guess I am very sensitive about that).

I heard no silence or click or something strange, But it seems to me that the sound had a less poor quality : is that possible ? How the sound can be affected by this option ?