NAME
MP4GetSampleIdFromTime - Get the sample id of a specified time
SYNTAX
#include <mp4.h>
MP4SampleId MP4GetSampleIdFromTime(
MP4FileHandle hFile,
MP4TrackId trackId,
MP4Timestamp when,
bool wantSyncSample = false
);
ARGUMENTS
hFile Specifies the mp4 file to which the operation applies.
trackId
Specifies the track to which the operation applies.
when Specifies the time in the track time scale that is desired.
wantSyncSample
Specifies if the returned sample id must correspond to a sample
whose sync/random access flag is true.
RETURN VALUES
Upon success, the sample id that occurs at the specified time. Upon an
error, MP4_INVALID_SAMPLE_ID.
DESCRIPTION
MP4GetSampleIdFromTime returns the sample id of the track sample in
which the specified time occurs.
The specified time should be in the track time scale. See
MP4ConvertToTrackTimestamp() for how to map a time value to this time
scale.
It is wise to use MP4GetSampleTime() with the returned sample id so one
can adjust for any difference between the specified time and the actual
start time of the sample.
If the calling application needs a sample that can be accessed randomly
then the ’wantSyncSample’ argument should be set to true. This could be
the case for a player that is implementing a positioning function and
needs to be able to start decoding a track from the returned sample id.
SEE ALSO
MP4(3) MP4GetSampleIdFromEditTime(3)