Many AV sync issues with FLAC conversion

[ryanjk333]

So I sure am enjoying the ability to convert HD audio losslessly to FLAC. But I do have a question and want to make sure that everything is alright before I rip a bunch of discs with audio converted to FLAC and run into problems.

With error logging turned on, I've seen a fair amount of AV sync issue errors before, but now when I am converting to FLAC I notice a huge amount of these errors. They pretty much all seem to happen in the last minute or two of the blu ray ripping process. When I watch/listen to the rip, what I've seen seems to be synchronized just fine, so I'm wondering why this is happening so much with the FLAC conversion and if there is something I should be worrying about.

Here is a small sample of the errors I receive. I would attach the complete log file, but it is larger than 1MB in size and won't go through. And I tried two different LPCM audio blu rays and both had a whole bunch of these same errors.

Code: Select all

004008:0010 AV sync issue in stream 1 at 1:33:12.383 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:12.576 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:12.672 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:12.768 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:12.863 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:13.056 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:13.152 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:13.248 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:13.343 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:13.536 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:13.632 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:13.728 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:13.823 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:14.016 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:14.112 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:14.208 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:14.303 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:14.496 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:14.592 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:14.688 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:14.783 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:14.976 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:15.072 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:15.168 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:15.263 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:15.456 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:15.552 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:15.648 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:15.743 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:15.936 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:16.032 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:16.128 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:16.223 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:16.416 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:16.512 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:16.608 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:16.703 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:16.896 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:16.992 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:17.088 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:17.183 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:17.376 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:17.472 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:17.568 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:17.663 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:17.856 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:17.952 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:18.048 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:18.143 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:18.336 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:18.432 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:18.528 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:18.623 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:18.816 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:18.912 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:19.008 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:19.103 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:19.296 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:19.392 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:19.488 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:19.583 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:19.776 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:19.872 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:19.968 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:20.063 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:20.256 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:20.352 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:20.448 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:20.543 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:20.736 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:20.832 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:20.928 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:21.023 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:21.216 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:21.312 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:21.408 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:21.503 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:21.696 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:21.792 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:21.888 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:21.983 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:22.176 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:22.272 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:22.368 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:22.463 with duration of 0.333ms : encountered overlapping frame, audio skew is +0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:22.656 with duration of 0ms : short audio gap was removed, audio skew is +0ms
004008:0010 AV sync issue in stream 1 at 1:33:22.752 with duration of 0.333ms : short audio gap was removed, audio skew is -0.333ms
004008:0010 AV sync issue in stream 1 at 1:33:22.848 with duration of 0.333ms : encountered overlapping frame, audio skew is +0ms

Thanks!

[joe42]

I don't know if those are bogus warnings or not, but if they are real, it is not surprising that you do not notice a problem.

For me, the audio has to be at least 40msec out of sync before I notice it, and even then it is difficult to notice.

The numbers in the warnings you posted are only a third of one millisecond, 0.333ms. It would take more than 100 of those adding up, all in the same direction, for it to be noticeable.

[robpdotcom]

Is this from a TrueHD track, and a seamless branching disc?

[ryanjk333]

Thanks for sharing, joe...good to know.

rob, This is a blu ray with an LPCM audio track. Had AV sync errors on another blu ray I have with LPCM audio, too. Not sure how to tell whether it's a seemless branching disc, but if you could tell me how to check, I will!

Thanks!

[robpdotcom]

I'm not sure if it matters for LPCM, but you can check if a disc is seamless branching when you open it with MakeMKV: Click on a title, and look at the title information on the right hand side of the window - on the line, "Segment map", you'll see a long string of numbers if the disc is seamless branching, or only one if it isn't.

[ryanjk333]

I'm not sure if it matters for LPCM, but you can check if a disc is seamless branching when you open it with MakeMKV: Click on a title, and look at the title information on the right hand side of the window - on the line, "Segment map", you'll see a long string of numbers if the disc is seamless branching, or only one if it isn't.

Ok, good to know! This particular disc does NOT have seemless branching, then. I'm guessing such small sync errors are probably not a big deal, but I would like to know for sure. Or perhaps MakeMKV is intentionally "adjusting" the audio stream to keep it in sync? Just making guesses here, though.

[mike admin]

It looks like timecodes are invalid in the source. What is the source - disc or MKV file?

[ryanjk333]

Source is technically a blu ray disc, but I had already ripped the entire disc contents to my hard drive with different software and was working with that backup. Sorry I can't try ripping from the original disc...someone else has it at the moment. I was just curious if these errors had anything to do with the FLAC conversion or if it's nothing to worry about. The MKV with FLAC audio that I made from it seems to play perfectly, with no "obvious" sync issues. Thanks!