Audio out of sync...

[redeemer-dk]

I just did the big 3 on a DVD and when i play it i notice that the audio isn't quite in sync with the lip movement. I think i know what the problem is but i'm not sure how to fix it.
My AC3 files that DIF4U has created have names like this:

VTS__01_P01-80-192K-[-40]ms(fixed)-ch2NotSpecified.AC3

I notice that it says "fixed" after the offset which probably means that it shortens the file in the beginning by 40 ms so the -40 ms offset isn't needed. Some of my AC3 files have a -80 ms offset and some have a -40ms offset. I have noticed that the out of sync audio is much more noticable when playing the titlesets that have the -80 ms audio, so my guess is that DIF4U has fixed my audio but the audio is still being played at the specified offset. So i have some questions...
Am i totally wrong here? And, how do i fix it?

Thanks in advance all,

-Rune Svendsen

[Matthew]

AC3s can only be cut in 32ms increments, so your -40ms delay will still be -8ms after being fixed. Your -80ms delay will be +16 ms after being fixed.

You shouldn't really notice desync of this magnitude though, so there may well be some other problem. Just pointing out sync won't be perfect (in theory) even if everthing goes to plan.

[redeemer-dk]

Then what's the point of "fixing" the audio files if nothing is fixed? Why not just leave them as they are in the beginning and specify the -40 ms delay on the backup DVD...
BTW, do you know a way to change the delay time in the AC3 header file? I know that there are a lot of programs that can change various values such as aspect ratio and format etc. in MPEG2 files, but does any program exist that can change the values in a header in an AC3 file (more precisely the offset)?

-Rune Svendsen

[Trahald]

Hrm

why do we fix it? because 16ms is better than 400ms. But more importantly, delays that small (16ms) of a delay is only noticable by (insert some extremely small fraction here) of the population.. as matthew eluded , there might be another issue at hand if you are noticing delay

Ive never noticed a sync problem with my backups

[redeemer-dk]

That's the reason i doubt an 8 ms delay is the problem. I can clearly see that the audio is out of sync and i'm pretty sure i wouldn't notice an 8 ms difference.
Could it be that Scenarist 2.7 supports audio offsets in AC3 files? Cause that's the version I'm using... not sure, just guessing here. Thanks for your help.

-Rune Svendsen

[HyperYagami]

Originally posted by redeemer-dk
.
Could it be that Scenarist 2.7 supports audio offsets in AC3 files?

no. that's no such thing as "ac3 audio delay offsets" or
"ac3 delay file header". the time difference lives within the VOBs.

my guess is your original has lip-sync problem to start with.