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Re: Keycode readers



I have been monitoring this thread for a few days and feel it would be helpful to 
chime in with some information from Evertz.

On October 16 Kay Sievert wrote:

> Now I'm having the same problem that the keycode isn't updating fast enough. 
> Our telecine-prep doesn't put leader in between cam. rolls, so the tailpunch 
> is sometimes only a few frames apart from the next headpunch.

Let me explain what is happening with KeyKode Break updating on the 4025
As you know, KeyKode occurs every half foot.  Unfortunately, there is no way to 
determine when the break has occurred until an out of sequence barcode is read.  This 
may be up to one half foot after the real splice.  (assuming the splice was in the 
middle of the barcode - worst case).  The point where the splice is detected is at the 
reader head, and so the 4025 attempts to delay the updating of the splice information 
into the VITC and characters so that it occurs in time with the splice going 
through the head.  To do this the 4025 uses the head offset number to determine how 
many barcodes must pass before the update will occur. Updates are done only on the 
reading of a barcode so that we can guarantee the accuracy of the update.  When the 
numbers update they will be frame accurate with the barcode on the film.

Our Key-Log software does do the math to calculate the out point correctly once the 
4025 has detected the break.  Alternately you can GPI the 4025 to generate the out 
point before the splice.

> Does the location of the readerhead to the gate make a difference? Here at 
> Foto-Kem, the readerheads on the mark III's are all mounted after the first 
> tensionarm and the next roller. Is there maybe a better location? Further 
> away from the gate?

Yes the reader head position can make a difference.  The location most commonly used it 
the one you have indicated.  Some others are locating the head on the gate side of the 
roller. Putting it further away will not improve the problem.
 
On October 18 Kevin Shaw wrote

> If you move the head further away, the keykode is updated before the new scene has 
> entered the gate and has been scanned.

Because of the way KeyKode occurs every half foot it is not possible to know exactly 
when the splice will go through the gate.  The 4025 attempts to minimize the update 
delay by calculating the closest barcode before or after the splice.  Closer to the 
gate is not always better.  You should notice that some updates will occur before and 
some after the actual splice goes through the gate.

On October 18 Kay Sievert wrote

> is there a way to just wire a  switch between the evertz and the reader to interrupt 
> keycode reading so once it has the new keycode, prerolling into the previous roll 
> doesn't affect the new keycode read?

On October 16 Hans Lehman wrote
> The keykode information in sent to the 4025 whenever the keykode reader
> successfully reads another barcode.  By switching off this serial line, the
> 4025 will simply count feet & frames, and will ignore any updates from the
> keykode reader.  At Encore Video, we modified the 4025s by installing a wire
> to the output of the RS232 receiver chip.  I'm not sure which chip offhand,
> but it's on the motherboard, in the back.  This line runs to a switch mounted
> on the colorists console.  Pressing the switch shorts the RS232 data to
> ground (crude,... but effective).  Handy for those times when prerolling over
> a splice would upset the 4025 for the first few feet of the take.> 

We do not recommend grounding the output of the RS-232 Receiver chip.  A better way 
would be to put a small relay or even a hard switch in line with the RS-232 output from 
the DigiSync or 5500 KeyKode Decoder ( You only need to disconnect one wire to make it 
work)  There is an internal resistor on the 4025 which will handle the input correctly 
when there is nothing connected (the switch is open)  The only caveat is that you need 
to make sure that you have read ( and the 4025 has updated) the new KeyKode from the 
new camera roll before you open the switch.

> One more - since that nice "JAM" button on the  evertz panel still doesn't work 

The JAM button on the 4025 doesn't have anything to do with KeyKode Jam modes.  It is 
used on the ARRI version of the software to control how the ARRI timecode gets used 
with the generator numbers.  That is the reason the front panel say "Not available" 
(not " not working") on the standard 4025 software.

On October 16 Ralph Edwards wrote:

> you have to have everything set up for Jam mode for it to "take" it and 
> go into jam.  Again, if I remember correctly, this means valid external 
> code present, film running and locked, then hit Jam.  However, without a 
> manual in front of me, I may be incorrect or incomplete here.

This is not exactly correct.  The LED indicator above the JAM button does indicate when 
the timecode mode of the 4025 is set to jam to external time code.  (The Gen Assign 
setting is set so that the Time is coming from RDR 1)  The Menus must be used to 
control the timecode JAM function because there are at least two modes that can be 
selected when not in JAM mode. There are also three modes that can be set up to 
determine what happens when the external timecode stops while you are in Timecode Jam 
mode.  The LED above the RDR 1 Button indicates when there is valid code coming into 
RDR 1.

Evertz is always happy to dialog with users to answer questions and resolve problems.
You can send your questions directly to our tech support group 
<eng at evertz.com> or contact us by Phone (905)-335-3700 or Fax (905-335-3573.
We also intend to provide product technical support on our web page in the near future 
<http://www.evertz.com>.

Regards,


Alan Lambshead,
Director of Engineering,
Evertz Microsystems Ltd..

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