Scott Dorsey wrote:
: At the first shot on the reel, the audio is in synch. At the last shot on
: the reel, the audio is out of synch.

: If you run the tape, how far in do you first notice that it's out of synch?

It's proportional. So in 2 hours it's off by .155 of a sec. In 1 hour it's off
by .0775 of a sec.... Etc...

--Leonid

Leonid Makarovsky wrote:
Scott Dorsey wrote:
: At the first shot on the reel, the audio is in synch. At the last shot on
: the reel, the audio is out of synch.

: If you run the tape, how far in do you first notice that it's out of synch?

It's proportional. So in 2 hours it's off by .155 of a sec. In 1 hour it's off
by .0775 of a sec.... Etc...

Right. But how far in do you NOTICE it? How far off can it be, before it is
a problem?

If it's two hours long, there should be PLENTY of places to cut a frame of
audio out here and there to match everything up.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
: Right. But how far in do you NOTICE it? How far off can it be, before it is
: a problem?


I start notice things when it's off by 2 NTSC frames which is 0.06 of a second.


Would you recommend jumping to zero crossing and keep inserting silences?

--Leonid

Leonid Makarovsky wrote:
Scott Dorsey wrote:
: Right. But how far in do you NOTICE it? How far off can it be, before it is
: a problem?

I start notice things when it's off by 2 NTSC frames which is 0.06 of a second.

Would you recommend jumping to zero crossing and keep inserting silences?

No, if the sound is slipping back, I would recommend cutting out video
frames at transitions instead.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
: No, if the sound is slipping back, I would recommend cutting out video
: frames at transitions instead.

That's a good idea. I haven't thought about it. I'll try it with my next
capture.

--Leonid

On or about 18 Oct 2004 18:56:07 -0400, Scott Dorsey allegedly wrote:

Leonid Makarovsky wrote:
Scott Dorsey wrote:
: Right. But how far in do you NOTICE it? How far off can it be, before it is
: a problem?

I start notice things when it's off by 2 NTSC frames which is 0.06 of a second.

Would you recommend jumping to zero crossing and keep inserting silences?

No, if the sound is slipping back, I would recommend cutting out video
frames at transitions instead.


With the error running at 0.0775 seconds per hour, that would mean only
2.3 frames (asssuming 30fps) in an hour. Find suitable places to remove 4
or 5 frames in the two hour program, and you're done.


Noel Bachelor noelbachelorAT(From:_domain)
Language Recordings Inc (Darwin Australia)

Leonid Makarovsky wrote:

Scott Dorsey wrote:
: At the first shot on the reel, the audio is in synch. At the last shot on
: the reel, the audio is out of synch.

: If you run the tape, how far in do you first notice that it's out of synch?

It's proportional. So in 2 hours it's off by .155 of a sec. In 1 hour it's off
by .0775 of a sec.... Etc...

I suppose a filter/plugin to do this doesn't exist (maybe I should write
one), but I would be awefully tempted to want to solve this problem by
throwing out individual samples instead of resampling. If you're off by
0.0775 seconds per hour, that's only 0.00215%, which is not even one
sample per second at the 44100 Hz sample rate and just over one sample at
48000 Hz. I'm sort of a purist, but I doubt it would be easy to notice
when one sample is removed here and there. It's equivalent to editing
out about 0.02 milliseconds of audio.

The code for a plugin to do this would be very simple. For a little
added flair, the plugin could look for periods of silence or quiet
parts (or parts without much high-frequency content or with lots of
high-frequency noise) and throw out more samples during those periods
and fewer at other times.

I should explain that if none of this makes sense in the context of this
discussion (or it has already been discussed), it might be because I
just got back from vacation and haven't been following the thread.
(By the way, anyone here ever do installed audio for a cruise ship?
This particular one might have had a deal with Yamaha, because everything
from pianos to drums to consoles was all Yamaha.)

- Logan

Logan Shaw wrote:
: I suppose a filter/plugin to do this doesn't exist (maybe I should write


During the video capture there exists an option to resample audio on the fly.
But I'm not sure it would be a good idea.

There's also an option to shift audio proportionally by number of %. I have
to contact the owner of the software package to find out what he's doing there.
If he just samples audio at say 48001Hz, then I'm good.

--Leonid

In article writes:

: If you run the tape, how far in do you first notice that it's out of synch?

It's proportional. So in 2 hours it's off by .155 of a sec. In 1 hour it's off
by .0775 of a sec.... Etc...

Do you notice that it's .0775 seconds out of sync? Do you have to look
at a time scale on the computer to know that it's out of sync or is
there some aural-visual cue that tells you that?

Frankly, I think that if you can see that it's 0.0775 seconds out of
sync, you've got a good imagination. What we're trying to get at is
whether you're seeking an exotic solution for a problem that isn't a
problem in practice.


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Mike Rivers wrote:
: Do you notice that it's .0775 seconds out of sync? Do you have to look
: at a time scale on the computer to know that it's out of sync or is
: there some aural-visual cue that tells you that?


Believe it or not I do notice if I look carefully. I don't notice .03 of a sec.
But .06 is somewhat noticeable.

--Leonid

"Mike Rivers" wrote in message
news:znr1098130242k@trad...

In article writes:

: If you run the tape, how far in do you first notice that it's out of
synch?

It's proportional. So in 2 hours it's off by .155 of a sec. In 1 hour
it's off
by .0775 of a sec.... Etc...

Do you notice that it's .0775 seconds out of sync? Do you have to look
at a time scale on the computer to know that it's out of sync or is
there some aural-visual cue that tells you that?

Frankly, I think that if you can see that it's 0.0775 seconds out of
sync, you've got a good imagination. What we're trying to get at is
whether you're seeking an exotic solution for a problem that isn't a
problem in practice.

Mr. Makarovsky has been flogging this question now in at
least a couple of newsgroups that I read. Frankly, it has taken
on the tone of a troll. He has ignored at least a dozen suggestions
for the most likely methods of fixing the issue (assuming that it
even exists). if he wants to tweak the length of the sound track
by .002% maybe we should just let him learn for himself.

Richard Crowley wrote:
: Mr. Makarovsky has been flogging this question now in at
: least a couple of newsgroups that I read. Frankly, it has taken
: on the tone of a troll. He has ignored at least a dozen suggestions
: for the most likely methods of fixing the issue (assuming that it
: even exists). if he wants to tweak the length of the sound track
: by .002% maybe we should just let him learn for himself.


Mr. Crowley, what went on in your head
Mr. Crowley, did you talk with the dead - Ozzy 1981...

Anyway, I have no time to troll the newsgroups. I posted it to this and
to rec.video.desktop. If you think it's a troll, just ignore the thread.
FYI, I have previously synched audio and video successfully when audio was
longer, but never done it when audio was shorter. Have a nice day.

--Leonid