dmTCAddTC(3dm) dmTCAddTC(3dm)
dmTCAddTC, dmTCAddFrames - digital media timecode mathematics
#include <dmedia/dm_timecode.h>
DMstatus dmTCAddTC [Toc] [Back]
( DMtimecode * result,
const DMtimecode *s1,
const DMtimecode *s2,
int *overflowunderflow )
DMstatus dmTCAddFrames [Toc] [Back]
( DMtimecode * result,
const DMtimecode *s1,
int frames,
int *overflowunderflow )
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).
result The result of the addition operation. Note that this must be a
valid pointer, and should not point to the same DMtimecode as s1
or s2.
s1, s2 The timecode operand(s) to be used in the addition.
frames The number of frames to add to the operand s1.
underflowoverflow
An optional argument so that the user of the library can tell if
an underflow or overflow condition occurred. If the app doesn't
care about overflow/underflow, it should pass in NULL.
Otherwise, underflowoverflow will be set to 0 (normal), a
positive number (overflow), or a negative number (underflow).
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dmTCAddTC(3dm) dmTCAddTC(3dm)
dmTCAddTC adds operand s1 to operand s2. It returns the result of the
addition in result. The tc_type of result will be the same as the tc_type
of the operands. It is required that the tc_type of s1 be the same as the
tc_type of s2. See NOTES for information on adding timecodes of differing
tc_type. dmTCAddTC will return DM_FAILURE if the addition failed. See
RETURN VALUE.
dmTCAddFrames adds frames video frames to operand s1 and returns the
result in result. The tc_type of result will be the same tc_type as s1.
It is acceptable for frames to be a negative value, but overflowunderflow
from dmTCAddFrames should be checked to verify that there was no
underflow condition.
If a DMtimecode operand (s1 or s2) contains an illegal timecode value
(e.g., a negative entry, invalid frame number, etc.), these functions
will return DM_FAILURE, and the contents of result will be undefined.
If the result of the addition overflows or underflows the 24 hour period,
these functions will return DM_SUCCESS, and the contents of result will
have wrapped to a 24 hour clock. The overflowunderflow parameter will
have been set, however, on an underflow or overflow condition.
dmTCAddTC and dmTCAddFrames return DM_SUCCESS upon successful completion
of the addition operation.
In order for DMtimecode's of differing tc_type (e.g., DM_TC_30_ND and
DM_TC_2997_4FIELD_DROP) to be added, they must first be converted to
either frames or seconds, and added as either frames or seconds, as
appropriate for the situation. Note that when adding DMtimecode's with
different tc_type's, different results may be obtained by adding them as
seconds or as frames--which is why dmTCAddTC does not allow two
DMtimecode's of different tc_type's to be added.
dmTCFromSeconds(3dm), dmTCToSeconds(3dm), dmTCFromString(3dm),
dmTCFromString(3dm), dmTCFramesPerDay(3dm), dmTCFramesBetween(3dm),
dmLTC(3dm), dmVITC(3dm)
PPPPaaaaggggeeee 2222 [ Back ]
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