dmTCToSeconds(3dm)					    dmTCToSeconds(3dm)

NAME    [Toc]    [Back]

     dmTCToSeconds, dmTCFromSeconds - digital media timecode mathematics

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/dm_timecode.h>

     DMstatus dmTCToSeconds    [Toc]    [Back]
	 ( const DMtimecode *tc,
	   double *seconds )

     DMstatus dmTCFromSeconds    [Toc]    [Back]
	 ( DMtimecode *	result,
	   const int tc_type,
	   const double	seconds	)

TYPES    [Toc]    [Back]

     DMtimecode	  A structure containing a representation of SMPTE time	code
		  on which certain mathematical	and utility functions can be
		  performed.  Can be used with:	 dmTCAddTC(3dm),
		  dmTCAddFrames(3dm), dmTCToString(3dm), dmTCFromSeconds(3dm),
		  dmTCToSeconds(3dm), dmTCFromString(3dm),
		  dmTCFramesPerDay(3dm), and dmTCFramesBetween(3dm).  Can also
		  be used with the dmLTC(3dm) and dmVITC(3dm) routines.	 See
		  also DMtimecode(3dm).

ARGUMENTS    [Toc]    [Back]

     result   The result of converting fractional seconds past midnight	into a
	      timecode value.


     tc	      The timecode value to convert into seconds.


     seconds  The number of fractional seconds past midnight to	convert, or
	      the result of converting a DMtimecode into fractional seconds
	      past midnight.


     tc_type  When converting from fractional seconds to a DMtimecode, the
	      timecode format into which the seconds should be converted.  See
	      tc_type(3dm).

DESCRIPTION    [Toc]    [Back]

     These functions provide a simple means of converting between fractional
     seconds past midnight and DMtimecode timecodes.

     When converting from seconds to timecode, a valid tc_type must be
     supplied (see tc_type(3dm)). The tc_type of result	will be	the same as



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dmTCToSeconds(3dm)					    dmTCToSeconds(3dm)



     the tc_type that is passed	to dmTCFromSeconds.

     For dmTCFromSeconds, the seconds value given will be rounded to the
     nearest frame.

     In	order to convert to and	from seconds, these routines need to assume
     some timecode rate	in frames per second.  They will choose	the rate given
     in	the DM_TC_RATE bits of the specified tc_type.  For drop-frame
     timecode, this is not the rate of the underlying video signal, and	over
     the long term there will be drift.	 See tc_type(3dm) for more information
     on	this.

RETURN VALUE    [Toc]    [Back]

     If	a DMtimecode operand (tc) contains an illegal timecode value (e.g., a
     negative entry, invalid frame number, etc.), dmTCToSeconds	will return
     DM_FAILURE, and the contents of seconds will be undefined.

     If	the number of seconds passed to	dmTCFromSeconds	is negative, or
     greater than the number of	seconds	in a 24-hour day, dmTCFromSeconds will
     return DM_FAILURE,	and the	contents of result will	be undefined.

     If	an invalid tc_type value is passed in to dmTCFromSeconds, DM_FAILURE
     is	returned.

     dmTCToSeconds and dmTCFromSeconds return DM_SUCCESS upon successful
     completion.

SEE ALSO    [Toc]    [Back]

     dmTCFromSeconds(3dm), dmTCToSeconds(3dm), dmTCFromString(3dm),
     dmTCFromString(3dm), dmTCFramesPerDay(3dm), dmTCFramesBetween(3dm),
     dmLTC(3dm), dmVITC(3dm)


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