More info on video/audio sync

[Roger Merchberger]

Otay - I posted a ton o'stuff last time, and no-one directly replied
"whoa - cool - thanks" so I'll *assume* (yes, I know the consquences)
that it was info-overload & it wasn't all that useful. I do, however,
have some info that might help...

2nd of wifey's Charmed episodes -- here's the audio offset:

estimated audio delay from first video -101.155556 ms
estimated audio delay from earliest video -34.422222 ms

I (again) averaged the two numbers, and set the audio offset to -66
ms. The audio still came out decent enough for me not to cry over --
but there was a point in the video where there was a sword striking a
wall - and I upon closer inspection (it took 3 rewinds) that the
video was leading the audio.

Now, IIRC the negetive offset of the numbers means that the audio is
leading the video initially, so this would suggest that I went too
far with the offset. I'd like to pose a SWAG (that's a Scientific
Wild Ass Guess - learned that in college! ;-) that the audio delay
from "earliest video" would have set the video dead-on, at least in
this instance.

I'd love to test that theory, but the serious lack of hard drive
space & CPU power precludes me from doing another 12-hour render just
to try it out.

What I will do is this: The next show that I find that has a loud
crack or something right in the beginning I'll CBR encode it (that's
only a 4-hour render) because when those are stopped, the initial
MPEG portion is still there - I'm currently using 2-pass VBR
encoding, and there's no output until after the first pass.

Oh, and one other tidbit of information - from my early testing,
don't trust "Burn-Proof" on a CD-Burner. This may very well cause
artifacts in your video. I have a 16X plextor (*beauty* drive! ;-)
and 2 CD's I burned with burn-proof at 16X had 3-4 glitches each, and
so far I've burned 1 at 12x, and a rewritable at 4x (same show), and
neither had glitches. I just burned a 2nd show at 12x, and I'm taking
it upstairs to my wife to preview.

Anyway, hope that helps, and I'll ease up on the "info-overload"...
but I am archiving the error messages just in case someone needs the
info - then I'll send it direct.

Roger "Merch" Merchberger


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