[jimz]

Hi
If I buy a digital cam corder and use my edirol for recording,
is there a standard time base for recording on both
to get it to sync. What program will do this sort of thing.

What mode to I record in ?


Thanks

Jim

[Mike Rivers]

jimz wrote:

If I buy a digital cam corder and use my edirol for recording,
is there a standard time base for recording on both
to get it to sync. What program will do this sort of thing.

What you call "standard time base" is what I call "good luck." Ideally
you'd synchronize the word clocks on the two recorders to eliminate time
creep between them, but since the R09 doesn't have a word clock or
digital audio input or output (regardles of what your video camera has
or doesn't have), you can't do that. So set them for the same sample
rate, generally 48 kHz for video work, and trust that the clock
frequencies are close enough to being the same so that you don't get too
far out of sync between edit points.

What mode to I record in ?

48 kHz, 16-bit will be fine.

--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[philper]

On Sep 5, 9:33 am, "jimz" wrote:
Hi
If I buy a digital cam corder and use my edirol for recording,
is there a standard time base for recording on both
to get it to sync. What program will do this sort of thing.

What mode to I record in ?

Thanks

Jim

It works ok--we use them as low cost backup recorders on video docs
where we are sending audio to the camera via wireless, and even as a
"plant" mic in scenes where we can't or won't use a wireless plant.
Syncing the audio up to the camera sometimes takes some detective work
to find a sound in both the camera mic track and the R09 (or etc)
track, but having found it it will hold sync for at least 10 min or
so.
A clap slate or a hand clap is a good idea. Don't forget to have your
camera mic on for a scratch/reference track to sync to. And roll the
R09 @ 48k.

Philip Perkins

[Jim Z]

Thanks for the reply.

I am somewhat shocked at the fact the
clocks on these devices are not very accurate.
I thought electronics has advanced to the point
where frames per second video and audio recording
could be done in perfect sync from device to device.

I guess I am mistaken.

However, what sort of program could be used to
"tweak" the tracks to stay in sync ? There must be a
way to stretch the time frame of the video with some sort
of markers that will ensure perfect timing with audio.
I would think it would be better to alter the video time
frame rather than the audio without noticable effects.

Jim

"philper" wrote in message
...
On Sep 5, 9:33 am, "jimz" wrote:
Hi
If I buy a digital cam corder and use my edirol for recording,
is there a standard time base for recording on both
to get it to sync. What program will do this sort of thing.

What mode to I record in ?

Thanks

Jim

It works ok--we use them as low cost backup recorders on video docs
where we are sending audio to the camera via wireless, and even as a
"plant" mic in scenes where we can't or won't use a wireless plant.
Syncing the audio up to the camera sometimes takes some detective work
to find a sound in both the camera mic track and the R09 (or etc)
track, but having found it it will hold sync for at least 10 min or
so.
A clap slate or a hand clap is a good idea. Don't forget to have your
camera mic on for a scratch/reference track to sync to. And roll the
R09 @ 48k.

Philip Perkins

[hank alrich]

Jim Z wrote:

Thanks for the reply.

I am somewhat shocked at the fact the
clocks on these devices are not very accurate.
I thought electronics has advanced to the point
where frames per second video and audio recording
could be done in perfect sync from device to device.

I guess I am mistaken.

Think about what a .0001% discrepancy implies over say, ten minutes,
with sample rates of 48 Khz. A tiny difference becomes obivous with the
passing of time.'

That's why more serious kit provides for locking to external clock so
that there are no differences between units.

However, what sort of program could be used to
"tweak" the tracks to stay in sync ? There must be a
way to stretch the time frame of the video with some sort
of markers that will ensure perfect timing with audio.
I would think it would be better to alter the video time
frame rather than the audio without noticable effects.

Most any DAW provides for time stretching or compressing of audio. The
better ones do it without glaringly obvious artifacts if not asked to
make drastic alterations.

I know nothing about video.

"philper" wrote in message
...
On Sep 5, 9:33 am, "jimz" wrote:
Hi
If I buy a digital cam corder and use my edirol for recording,
is there a standard time base for recording on both
to get it to sync. What program will do this sort of thing.

What mode to I record in ?

Thanks

Jim

It works ok--we use them as low cost backup recorders on video docs
where we are sending audio to the camera via wireless, and even as a
"plant" mic in scenes where we can't or won't use a wireless plant.
Syncing the audio up to the camera sometimes takes some detective work
to find a sound in both the camera mic track and the R09 (or etc)
track, but having found it it will hold sync for at least 10 min or
so.
A clap slate or a hand clap is a good idea. Don't forget to have your
camera mic on for a scratch/reference track to sync to. And roll the
R09 @ 48k.

Philip Perkins


--
ha
Iraq is Arabic for Vietnam

[Richard Crowley]

"Jim Z" wrote ...
I am somewhat shocked at the fact the
clocks on these devices are not very accurate.
I thought electronics has advanced to the point
where frames per second video and audio recording
could be done in perfect sync from device to device.

What you are asking for is equivalent to a pair of $5
knockoff chineese wris****ches to stay within 1 second
of each other for a year. Even professional equipment is
not expected to maintain this kind of absolute long-term
accuracy.

I guess I am mistaken.

Your expectations greatly exceed the state of the art
and/or you don't understand the technological issues.

There are still many techniques for directly connecting,
("genlock") or coordinating ("jamming time-code"), etc.
These are regularly discussed over on the production
sound newsgroup: news:rec.arts.movies.production.sound

However, what sort of program could be used to
"tweak" the tracks to stay in sync ? There must be a
way to stretch the time frame of the video with some sort
of markers that will ensure perfect timing with audio.

The customary method these days (which I frequently
use myself) is to roll the camera and the audio recorder,
preferably with some sort of visible/audible "sync" point.
In Hollywood, this is done with the slate/clap-sticks.
It "slates" the shot so the editors kow what it is, and
when the sticks come together that is the point where
they slide the video and/or audio tracks together to
establish the starting sync point.

In a live environment where it would be disruptive to do
a clap-stick slate I sometimes have someone just give
me a single hand-clap, or some other visible/audible
sync point. But even in the complete absense of a
reference, it isn't that difficult to line up the video and
audio tracks with modern video NLE systems.

Modern equipment, even relatively inexpensive consumer
camcorders and digital (not analog) audio recorders, have
good enough 29-cent crystals to stay more or less in sync
for maybe 10~15 minutes. This is plenty good enough for
film-style production, where individual scenes are shot in
isolation. But clearly not good enough for long-form things
like concert videos, etc.

I would think it would be better to alter the video time
frame rather than the audio without noticable effects.

Indeed, it is common to tweak the video track to match
the sound track. The audio track is the "master" so that
you don't have to do bad things to it like trying to stretch
or shorten it "slightly". It is rare that this can be done
without doing audible violence to the sound track. But
fortunately, it is rarely necessary.

It is easy enough to slip the video to match the audio,
cutting or duplicating a frame here or there as needed.
Viewers are much more forgiving about tiny glitches in
the video than they are with tweaks to the audio track.

Frequently you can get away with making a sync
adjustment like this only between songs, etc. And we
usually roll at least 2 cameras so that we can alternate
between a wide shot of the stage (for example) and
close-ups of the performers, audience reaction, etc.
At every point where we switch between cameras
it is trivial to bring the video back into sync with sound.
It takes much less time to do it than it took you to read
about it.

There are many common techniques for this, but this
is already off-topic for r.a.p. Video production questions
like this are discussed regularly in the video newsgroup:
news:rec.video.desktop

[hank alrich]

Richard Crowley wrote:

What you are asking for is equivalent to a pair of $5
knockoff chineese wris****ches to stay within 1 second
of each other for a year.

Richard, that is _wonderfrul_! Thanks for the chuckle.

--
ha
Iraq is Arabic for Vietnam

[Mike Rivers]

Jim Z wrote:

I am somewhat shocked at the fact the
clocks on these devices are not very accurate.

Oh, they're VERY accurate, which is why you can usually get away with
"wild" (= no) sync for a reasonable length scene. But they're not
perfect. Most of them use a crystal originally designed for TV sets that
costs just a few pennies because they make so many of them. Still, no
two are exactly alike, and in an hour, even if they're different by just
a few hertz, the error accumulates enough so notice.

I thought electronics has advanced to the point
where frames per second video and audio recording
could be done in perfect sync from device to device.

"Sync" means that there's something tying them together so that they run
off the same clock. When cameras were driven by spring-wound motors and
recorder speed was determined by a DC motor and friction between the
tape and capstan, you needed a common time reference for both. We
graduated to SMPTE time code, and now we have word clock. Each system
provided more accurate synchronization.

However, what sort of program could be used to
"tweak" the tracks to stay in sync ? There must be a
way to stretch the time frame of the video with some sort
of markers that will ensure perfect timing with audio.

Most A/V workstation programs have time stretch functions. Vegas is a
popular one on a PC. However, this may seem like the layz way to
accomplish synchronization but it's not a very good way. Just because
the beginning and end line up doesn't mean that every point in the
middle will line up. Generally the way these things go, you'll want to
do some editing and you'll be chopping up scenes, so you chop up the
audio along with the video. Because the speed is sufficiently accurate,
if you line them up at the beginning, in the 30 seconds to five minutes
before the next edit, the tracking will be close enough not to worry
about it. But if the video runs continuously for an hour, you'll
probably need to adjust the audio at a couple of points if
synchronization is important. You need to look for "hit" points and line
those up. For instance if you're doing a video of a band, when there's a
close-up of the drummer, you want to hear the drum beat when you see the
stick hit the drum. But if it's a long shot, you don't care about such
precise accuracy.




--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[jimz]

Thank you all for the replies.
I appreciate the insight.

Might I suggest in the future we start asking designers
to build in an option to sync devices with perhaps a
satellite signal (gps or cell technology) as a universal time
base.

There are also pulsars in our galaxy that may be suited but
the antenna gets real large.



JMHO

Jim

"Mike Rivers" wrote in message
news:Gztwk.628$1a2.115@trnddc04...
Jim Z wrote:

I am somewhat shocked at the fact the
clocks on these devices are not very accurate.

Oh, they're VERY accurate, which is why you can usually get away with
"wild" (= no) sync for a reasonable length scene. But they're not perfect.
Most of them use a crystal originally designed for TV sets that costs just
a few pennies because they make so many of them. Still, no two are exactly
alike, and in an hour, even if they're different by just a few hertz, the
error accumulates enough so notice.

I thought electronics has advanced to the point
where frames per second video and audio recording
could be done in perfect sync from device to device.

"Sync" means that there's something tying them together so that they run
off the same clock. When cameras were driven by spring-wound motors and
recorder speed was determined by a DC motor and friction between the tape
and capstan, you needed a common time reference for both. We graduated to
SMPTE time code, and now we have word clock. Each system provided more
accurate synchronization.

However, what sort of program could be used to
"tweak" the tracks to stay in sync ? There must be a
way to stretch the time frame of the video with some sort
of markers that will ensure perfect timing with audio.

Most A/V workstation programs have time stretch functions. Vegas is a
popular one on a PC. However, this may seem like the layz way to
accomplish synchronization but it's not a very good way. Just because the
beginning and end line up doesn't mean that every point in the middle will
line up. Generally the way these things go, you'll want to do some editing
and you'll be chopping up scenes, so you chop up the audio along with the
video. Because the speed is sufficiently accurate, if you line them up at
the beginning, in the 30 seconds to five minutes before the next edit, the
tracking will be close enough not to worry about it. But if the video runs
continuously for an hour, you'll probably need to adjust the audio at a
couple of points if synchronization is important. You need to look for
"hit" points and line those up. For instance if you're doing a video of a
band, when there's a close-up of the drummer, you want to hear the drum
beat when you see the stick hit the drum. But if it's a long shot, you
don't care about such precise accuracy.




--
If you e-mail me and it bounces, use your secret decoder ring and reach me
he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Mike Rivers]

jimz wrote:

Might I suggest in the future we start asking designers
to build in an option to sync devices with perhaps a
satellite signal (gps or cell technology) as a universal time
base.

That would increase the price of the devices to the point where most
people wouldn't want to buy them (which would further increase the
prices). Besides, it wouldn't be a significant improvement over using
their internal clocks. If you're willing to pay a professional price,
professional equipment is available right now. A decent digital video
camera with decent digital audio would make recording with an external
recorder unnecessary.


--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Jim Z]

I really don't see how it would create a significant
price increase.

The cell phone technology and gps is getting cheaper
every year. Seems to me this may be the future.

Jim

"Mike Rivers" wrote in message
news:NWvwk.635$sq3.621@trnddc07...
jimz wrote:

Might I suggest in the future we start asking designers
to build in an option to sync devices with perhaps a
satellite signal (gps or cell technology) as a universal time
base.

That would increase the price of the devices to the point where most
people wouldn't want to buy them (which would further increase the
prices). Besides, it wouldn't be a significant improvement over using
their internal clocks. If you're willing to pay a professional price,
professional equipment is available right now. A decent digital video
camera with decent digital audio would make recording with an external
recorder unnecessary.


--
If you e-mail me and it bounces, use your secret decoder ring and reach me
he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[[email protected]]

On 2008-09-07 said:
I really don't see how it would create a significant
price increase.
The cell phone technology and gps is getting cheaper
every year. Seems to me this may be the future.
Because what Mike's telling you is that the technology
exists to do what you want right now without having to play
games with cell phone technology etc. IT's called buy
professional equipment! Last thing I want is cell phone
"technology radiating junk to talk to cell sites close to
low level audio.

Professional gear has capability to handle word clock sync,
or to handle timecode. Get pro level gear, or at least
learn to use a clapper or other device to help you line up
audio and video.

PEople who do audio for video and film sound deal with this
every day, reliably and without external sync from cell
phone or gps based technology. You're wondering why folks
don't reinvent the wheel so you can use consumer gear.
Ain't gonna happen.




Richard webb,
replace anything before at with elspider

[Scott Dorsey]

I really don't see how it would create a significant
price increase.
The cell phone technology and gps is getting cheaper
every year. Seems to me this may be the future.

It's not the future, because it doesn't solve any problem that wasn't
already solved in the 1970s. Technology that doesn't solve problems
doesn't help anyone.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Mike Rivers]

Scott Dorsey wrote:

It's not the future, because it doesn't solve any problem that wasn't
already solved in the 1970s. Technology that doesn't solve problems
doesn't help anyone.

Only if you re-invent the problem so you can find a new solution. What's
that three letter acronym that was common a few years back about fear
and uncertainty?

Richard had a good point about cell phones too near audio equipment.

--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[jimz]

Yes, I agree
professional equipment
but you need to spend $$$$$$$$$$$$$$$$$$$$$

I'm an amateur I want to spend $$


wrote in message
. ..

On 2008-09-07 said:
I really don't see how it would create a significant
price increase.
The cell phone technology and gps is getting cheaper
every year. Seems to me this may be the future.
Because what Mike's telling you is that the technology
exists to do what you want right now without having to play
games with cell phone technology etc. IT's called buy
professional equipment! Last thing I want is cell phone
"technology radiating junk to talk to cell sites close to
low level audio.

Professional gear has capability to handle word clock sync,
or to handle timecode. Get pro level gear, or at least
learn to use a clapper or other device to help you line up
audio and video.

PEople who do audio for video and film sound deal with this
every day, reliably and without external sync from cell
phone or gps based technology. You're wondering why folks
don't reinvent the wheel so you can use consumer gear.
Ain't gonna happen.




Richard webb,
replace anything before at with elspider

[Scott Dorsey]

jimz wrote:
Yes, I agree
professional equipment
but you need to spend $$$$$$$$$$$$$$$$$$$$$

I'm an amateur I want to spend $$

Then you're going to have to do some cutting and pasting. Life is like that.
Either you can spend money or you can spend time. The reason folks buy
professional equipment is because it saves them time. If your time is worth
less than the equipment, it's not worth it for you.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

On 2008-09-08 said:
but you need to spend $$$$$$$$$$$$$$$$$$$$$
I'm an amateur I want to spend $$
then your BEST bet is to figure out how they did it before
such sync technologies existed, I.E. clappers, etc. and use
those techniques. otHERWISE, GET PRO GEAR.

Otherwise, "YOU CAN'T GET THERE FROM HERE."
A hint for you though: Even with modern sync methods they
still find clappers and other slating techniques quite
useful when all else fails.
Check the archives here and in
rec.arts.movies.production.sound to see what I"m talking
about. I'm pre-coffee and don't want to spend that much
effort typing right now g.



Richard webb,
replace anything before at with elspider

[Scott Dorsey]

Chel van Gennip wrote:
In fact it is much easier now than it was in the past. Some major
differences: Video comes with (poor quality) audio in sync, drift
between different digital sources is minimal, I see a drift of about 1
frame per 30 minutes, and syncing external audio to video with an audio
track in sync is not a problem in a NLE system showing the envelopes of
both audio tracks.

If this is the case, why does broadcast TV today so often have screwy
synch? Sometimes it's more than just two or three frames, even.
--scott

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

[Mike Rivers]

On Sep 8, 7:07 pm, (Scott Dorsey) wrote:

If this is the case, why does broadcast TV today so often have screwy
synch? Sometimes it's more than just two or three frames, even.

I suspect that this is a result of mangling in transmission, though I
never get to see a video broadcast product straight out of the editor.

[Richard Crowley]

"Scott Dorsey" wrote ...
Chel van Gennip wrote:
In fact it is much easier now than it was in the past. Some major
differences: Video comes with (poor quality) audio in sync, drift
between different digital sources is minimal, I see a drift of about 1
frame per 30 minutes, and syncing external audio to video with an audio
track in sync is not a problem in a NLE system showing the envelopes of
both audio tracks.

If this is the case, why does broadcast TV today so often have screwy
synch? Sometimes it's more than just two or three frames, even.

That is a distribution problem, not a production problem.
It would be very rare for audio and video to be out of sync
when it leaves Master Control. But there are plenty of
opportunities for video to get delayed in some sort of
processing that doesn't involve audio (or doesn't involve it
to the same extent.): compression; decompression; multiplexing;
demultiplexing; overlaying; frame-syncing; error correction, etc.

I thought I heard about some proposed scheme to automaticaly
detect loss of lip-sync and restore it.

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