mvGetBoundary(3dm)

NAME
     mvGetBoundary: mvGetMovieBoundary, mvGetTrackBoundary - get timing
     information about movie or track


SYNOPSIS
     #include <dmedia/moviefile.h>

     DMstatus mvGetMovieBoundary( MVid movie,
              MVtime time, MVtimescale timeScale,
              MVdirection Direction, MVboundtype BoundType,
              int numMedia, DMmedium *medium,
              MVtime *returnTime );

     DMstatus mvGetTrackBoundary( MVid track,
              MVtime time, MVtimescale timeScale,
              MVdirection Direction, MVboundtype BoundType,
              MVtime *returnTime );


DESCRIPTION
     Each track is made up of frames, each of which can be typed.  Current
     frame types supported are key frames (MV_FRAMETYPE_KEY) or delta frames
     (MV_FRAMETYPE_DELTA). Frames can be grouped into chunks and/or edit
     atoms.  mvGetMovieBoundary and mvGetTrackBoundary allow the user to get
     at this information.

     Valid values for MVdirection are: MV_FORWARD and MV_BACKWARD.  Valid
     values for MVboundtype are: MV_FRAME, MV_KEYFRAME, MV_TRACKDATA,
     MV_EDITATOM.

     mvGetMovieBoundary takes a time cursor, described in user's timeScale, a
     Direction for searching, and a boundtype that the user is looking for.
     Users also need to specify the media he/she is interested in, passed as
     an array in medium, with numMedium specifying the number of medium to
     look for in the array.  The time for the concerned boundary is returned
     in returnTime.  If the cursor time passed in to this function happens to
     be the boundtype described in BoundType, the time for the next/prev
     boundary will be returned.

     mvGetTrackBoundary takes a track, a time cursor, a time scale, a
     direction, and a boundtype and returns the time for the boundary being
     searched for.

     If no more valid boundaries can be found between the time passed in and
     the end of the track (tail of the track if direction is forward and head
     of the track if direction is backward), DM_FAILURE is returned and the
     error code will be set to MV_TIME_OUT_OF_RANGE.

     These functions return DM_SUCCESS if a valid time boundary could be found
     and returned.  Otherwise, it returns DM_FAILURE, and the error may be
     retrieved by mvGetErrno(3dm).
EXAMPLES
          /*
           * this piece of code describes how to find all the times for the
           * key frames in a track.
           */

          #include <moviefile.h>

          void ListTrackKeyFrameTimes( MVid track )
          {
              MVtimescale timeScale;
              MVtime      lastKeyFrame = 0;
              MVtime      cursor = 0;
              timeScale = mvGetTrackTimeScale( track );
              mvGetTrackBoundary( track,
                                  mvGetTrackDuration( track, timeScale ), timeScale,
                                  MV_BACKWARD, MV_KEYFRAME,
                                  &lastKeyFrame );
              while( cursor < lastKeyFrame )
              {
                  MVtime tmp;
                  mvGetTrackBoundary( track, cursor, timeScale,
                                      MV_FORWARD, MV_KEYFRAME, &tmp );
                  fprintf( stderr, "key frame found at : %lld0, tmp );
                  cursor = tmp;
              }
          }



SEE ALSO
     mvIntro(3dm), mvGetTimeScale(3dm), mvGetErrno(3dm).