;[vcr.cal]	Xcal library and help for macros related to video tape timing.
;
;		To load this library type: "xcal /c /l:*vcr.cal"
;
/NE					;Disable XCAL file echoing
"Loading  vcr.cal; video tape related macros.\n\n"
/SS/SQ					;Set Quiet mode
;
SP2LP(Time)='/O:60 (Time)*2'
SP2EP(Time)='/O:60 (Time)*3'
LP2SP(Time)='/O:60 (Time)/2'
LP2EP(Time)='/O:60 (Time)*3/2'
EP2SP(Time)='/O:60 (Time)/3'
EP2LP(Time)='/O:60 (Time)*2/3'
"Defined: SP2LP(Time),   LP2SP(Time),   EP2SP(Time)\n"
"         SP2EP(Time),   LP2EP(Time),   EP2LP(Time)\n\n"

SP(Time)='(Time)*3'
LP(Time)='(Time)*3/2'
EP(Time)='Time'
"Defined: SP(Time),      LP(Time),      EP(Time)\n\n"

ShowTime(T)='/O:60 /SE EP2SP(T) "=SP" EP2LP(T) "=LP" T "=EP\n\n"'
Free120(TimeUsed)='/S:Q X=Int(3600*(6-(TimeUsed)))/3600 /O:10 ShowTime(X) X'
Free160(TimeUsed)='/S:Q X=Int(3600*(8-(TimeUsed)))/3600 /O:10 ShowTime(X) X'
"Defined: Free120(TimeList),            Free160(TimeList)\n\n"

"For help with all VCR functions type:  /h:vcr\n\n"
;
/SE	;Turn Quiet mode off
/Q	;Exit now if loaded with XCAL's command switch "/L:*vcr.cal"
;
;**********************************************************************
;*******	    Start of  vcr.cal  Help Section		*******
;**********************************************************************
;HelpSection VCR Macros
;HelpStart FUNCTION,FUNCTIONS,EXTERNAL,VCR
The following VCR "Conversion" functions convert time in one recording mode
to time in another.  For example: SP2LP(Time) answers the question "How long
a program can I record in LP mode on the same length of tape as an SP mode
program of length 'time'?".  'Time' must be specified in hours or sexagesimal
notation and the result is always displayed in sexagesimal (ie. :hh:mm:ss).

;HelpStart SP2LP,SP2LP(X)
SP2LP(Time)       Convert VCR video tape SP time to LP time.
;HelpEnd   SP2LP,SP2LP(X)
;HelpStart SP2EP,SP2EP(X)
SP2EP(Time)       Convert VCR video tape SP time to EP time.
;HelpEnd   SP2EP,SP2EP(X)
;HelpStart LP2SP,LP2SP(X)
LP2SP(Time)       Convert VCR video tape LP time to SP time.
;HelpEnd   LP2SP,LP2SP(X)
;HelpStart LP2EP,LP2EP(X)
LP2EP(Time)       Convert VCR video tape LP time to EP time.
;HelpEnd   LP2EP,LP2EP(X)
;HelpStart EP2SP,EP2SP(X)
EP2SP(Time)       Convert VCR video tape EP time to SP time.
;HelpEnd   EP2SP,EP2SP(X)
;HelpStart EP2LP,EP2LP(X)
EP2LP(Time)       Convert VCR video tape EP time to LP time.

;HelpEnd   EP2LP,EP2LP(X)

;HelpStart FREE120,FREE120(X),FREE160,FREE160(X)
The VCR 'Free' functions compute and return the amount of "Free Time" at the
end of a video tape.  Both functions accept either the time-used in EP mode,
or a TimeList.  A TimeList is the SUM of a list of times used, specified in
the appropriate recording modes.

For example: 	A 6 hour (T120) video tape has 3 programs recorded on it
		as follows:

		Program-1   SP-Mode   55 Minutes
		Program-2   LP-Mode   1 Hour 30 Minutes
		Program-3   EP-Mode   20 Minutes

		The "Free Time" at the end of the tape could be computed as:

		Xcal>unused=free120(SP(:0:55:00)+LP(:1:30:00)+EP(:0:20:00))
		:+0:13:20=SP    :+0:26:40=LP    :+0:40:0=EP

		unused=:+0:40:0
		Xcal>

FREE120(X)	Returns T120 (6 hour) video tape free time 
FREE160(X)	Returns T160 (8 hour) video tape free time 

;HelpEnd   FREE120,FREE120(X),FREE160,FREE160(X)
;HelpEnd   FUNCTION,FUNCTIONS,EXTERNAL,VCR
;**********************************************************************
;*******		   End of vcr.cal			*******
;**********************************************************************