www.makemkv.com

So I have encountered something that has me scratching my head.....

I used MakeMKV to rip a 2004 DVD release of Star Wars. When ripping from disc a small AV sync error was noted:

Saving 1 titles into directory
AV synchronization issues were found in file '01.mkv' (title #2)

AV sync issue in stream 1,2,3 at 1:00:41.632 with duration of 39.366ms : audio gap - 1.23 missing frame(s)

1 titles saved

After ripping from disc I noticed that I mislabeled on of the subtitle tracks. I, therefore, used MakeMKV to remux the extracted mkv file with renamed track titles (rather than go back and rerip the DVD). During the remux I got another sync error:

Saving 1 titles into directory
AV synchronization issues were found in file '01.mkv' (title #1)

AV sync issue in stream 1,2,3 at 1:00:41.671 with duration of 39ms : broken timecode, apparent audio skew is +39ms

1 titles saved


So what is going on here? I thought MakeMKV took care of all AV synchronization during extraction from disc, such that there should be no AV sync issues during subsequent processing of the extracted MKV files.

Yes I know the time displacements are very small and will not be noticed, I am just trying to understand what MakeMKV is doing.

Anyone seen anything like this before?

I have been doing a bit more exploration with this and it seems that about 20% of my MakeMKV rips display a second round of AV sync errors if I remux the ripped video using MakeMKV. This oddity seems to span all disc types I have tried (some MGM discs such as James Bond, some Fox discs such as Star Wars, some Disney/Pixar discs, some discs with multiple Angles, some discs with single Angles, etc.).

My conclusion is that it seems like MakeMKV is not correcting the AV sync problems it encounters during ripping.

For giggles here is another example from a DVD rip of Dr. No:

MakeMKV Rip Log:
AV synchronization issues were found in file (title #4)

AV sync issue in stream 1,3,4,5 at 0:55:27.616 with duration of 41.666ms : audio gap - 1.302 missing frame(s)

AV sync issue in stream 2 at 0:55:27.626 with duration of 31ms : audio gap - 2.906 missing frame(s)
1 titles saved

MakeMKV Remux Log:
AV synchronization issues were found in file (title #1)

AV sync issue in stream 1,3,4,5 at 0:55:27.658 with duration of 42ms : broken timecode, apparent audio skew is +42ms

AV sync issue in stream 2 at 0:55:27.658 with duration of 31.333ms : broken timecode, apparent audio skew is +31.333ms
1 titles saved