From: killeen@spcvxb.spc.edu (Jeff Killeen)
Newsgroups: rec.video
Subject: Re: VISCA FIRST LOOK
Date: 6 Sep 92 05:55:09 GMT
Organization: SPC Community Access System

> The VISCA system works with command packets.  The basic format is...
> 
> 	Header		Message		Terminator
> 	------		----------	-----------------------------
> 	1 byte		1-14 bytes	1 byte (Always = 255 decimal)
> 
> Header Normal
> 
> 	Bit 0-2	= Destination address (0-7)
> 	Bit 3	= Always 0
> 	Bit 4-6 = Source address (0-7)
> 	Bit 7	= Always 1
> 
> Header Broadcast
> 
> 	Bit 0-2	= Always 0
> 	Bit 3	= Always 1
> 	Bit 4-6	= Source address (0-7)
> 	Bit 7	= Always 1
> 
> Message
> 
> 	Byte 1		= Format type		(Packet byte 2)
> 	Byte 2		= Category code		(Packet byte 3)
> 	Byte 3		= Format info		(Packet byte 4)
> 	Bytes 4-14	= Message body		(Packet bytes 5-15)
> 
> Example of Search and Play at a frame - Vdeck is the first VISCA device (i.e.
> address 0) - Example is in HEX... 
> 
> 	80 01 02 03 21 hh mm ss zz 28 FF
> 
> 	hh = Hours
> 	mm = Minutes
> 	ss = Seconds
> 	zz = Frames

I am still waiting for my VISCA manual but in the mean time I plugged the Vdeck
and a Powerbook into my PDP-11 and did some VISCA net sniffing.  It comes with
a basic control disk that can be used in a MAC.  This is not editing control
software but it drives the basic Vdeck functions.  Programing this should be
real easy.  Here are some samples of the packets... 

--------------------------------------------------------------------------------
[all HEX codes]

CTL Computer.... TO Vdeck VCR.......81 01 02 01 28 FF <--- Command to Vdeck
Vdeck VCR....... TO CTL Computer....90 41 FF          <--- Confirms it got it
Vdeck VCR....... TO CTL Computer....90 51 FF          <--- Confirms it did it

PLAY

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 00 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

STOP

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 28 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

PLAY

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 20 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

PAUSE

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 02 02 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

FRAME FORWARD

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 02 03 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

FRAME BACK

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 03 21 00 10 11 12 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF <- This is not sent until the
						location is reached.

SEARCH TO 0:10:11:12 AND THEN PLAY

You can also search to location and pause or search to location and stop.

There is also a command that will instruct the Vdeck to stop when it reaches a
tape location.  When that location is reached the Vdeck will pause and send a
"90 51 FF" packet.  This will allow you setup start and stop points for an
edit.  Because there is an internal VISCA clock (H:MM:SS:TTT (TTT=tick)) that
you can read it is very likely you can setup adjustment factors for pre-roll
and spool-up to obtain accurate edits.  Note the VISCA clock is not the same as
the RC time code counter (H:MM:SS:FF). 

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 00 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

STOP

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 08 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

FF

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 00 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

STOP

--------------------------------------------------------------------------------

CTL Computer.... TO Vdeck VCR.......81 01 02 01 10 FF 
Vdeck VCR....... TO CTL Computer....90 41 FF 
Vdeck VCR....... TO CTL Computer....90 51 FF 

REW

--------------------------------------------------------------------------------

One interesting note - if you have a Control-L/LANC editor like a RM-E300/700,
Vidtronics, or FutureVideo editor you can't use it with the Vdeck.  You have to
have something that talks VISCA instead of LANC - even though what VISCA does
is convert the VISCA commands to LANC. 

One other note - the Vdeck is small.  It is about half the size of EV-S900 or a 
EV-S3000.