[mythtv-users] Mytharchive errors

[Rod Smith]

On Monday 15 December 2008 07:51:50 pm Harry Devine wrote:
> Rod Smith wrote:
> > If your DVD ends up with out-of-sync sound, you can use the audio delay
> > option in my script (the final option) to adjust it. You'll need to
> > measure or guesstimate how much it's off and enter the appropriate
> > option.
> > Unfortunately, this may take some trial and error, and you'll be starting
> > over from scratch. This will go much quicker if you can create a small
> > test file (just a minute or so in length).
>
> I've been playing around with the delay and I have a quick question:  on
> my 1st try I used 0 and the sound was just barely out of sync.  The
> second time I tried 3 since that was what it seemed to be off by.  Well,
> that got much worse.  So, my question is: can I put in negative values
> for the delay?  If not, and 0 is the best I can do, is there anything
> that I can do video-wise to sync them up?

Yes, you can use negative values. Also, note that the delay in mencoder (and 
hence my script) is in seconds, so using 3 as the value is really huge. 
Personally, I start noticing audio sync problems at about 60 milliseconds 
(ms; thousandths of a second), and anything over 100ms is extremely annoying.

A tip: If you can play the file via MythTV, there's an audio sync adjustment 
in the standard player. You can use that to fine-tune it, then copy the value 
from there; however, MythTV measures the value in milliseconds, so you'll 
need to divide by 1000 (you can enter decimal values, such as 0.06 or -0.08). 
Also, MythTV and mencoder reverse the polarity, so if you need a positive 
value in MythTV you'll need a negative value in mencoder (and my script) and 
vice-versa. Of course, this won't work if you can't hear audio in your MythTV 
setup, as I believe was your situation for files with AC3 audio the last time 
you posted. If the audio delay is the same in your original file as in the 
transcoded version, though, you can use the original to estimate the amount 
of adjustment you'll need. Alternatively, you can (and should) check your 
MythTV audio options to see if you can enable proper handling of AC3 audio.

-- 
Rod Smith