mvGetTrackDataFieldInfo(3dm)

NAME
     mvGetTrackDataFieldInfo, mvSetTrackDataFieldInfo, mvTrackDataHasFieldInfo
     - get track data info


SYNOPSIS
     #include <dmedia/moviefile.h>


     DMstatus mvGetTrackDataFieldInfo( MVid track, int index,
                              size_t *firstField,
                              off64_t *gap,
                              size_t *secondField );

     DMstatus mvSetTrackDataFieldInfo( MVid track, int index,
                              size_t firstField,
                              off64_t gap,
                              size_t secondField );

     DMboolean mvTrackDataHasFieldInfo( MVid track, int index );


DESCRIPTION
     The data to describe a single image in an image track may be made up of
     two fields.  In a QuickTime file, an auxillary table can be stored in the
     meta data to describe the sizes and relative positions of these fields.
     These functions allow users to get at field information.  Currently, this
     feature is only supported on QuickTime files.

     mvTrackDataHasFieldInfo

     This function must be called to determine whether a chunk of data has
     field information.  The function returns DM_TRUE if field information is
     available and DM_FALSE otherwise.  An error will occur if the track is
     invalid (error code: MV_BAD_ID) or if the index is out of range (error
     code: MV_PARAM_OUT_OF_RANGE).  Legal indices can be found by using the
     function mvGetTrackNumDataIndex.

     mvGetTrackDataFieldInfo

     This function fetches the field information for a particular data chunk
     in a track.  If the function succeeds:

     firstField will contain the size of the first field

     gap will contain the size of the gap between the first and the second
     field as written in the file

     secondField will contain the size of the second field

     The function can fail under the following conditions:
     1. if track is invalid.  (error code: MV_BAD_ID) 2. if index is out of
     range. (error code: MV_PARAM_OUT_OF_RANGE) 3. if the data is not of image
     type or is not interlaced. (error code:  MV_INVALID_DATA_TYPE) 4. if the
     information is not available. (error code: MV_INFO_NOT_AVAILABLE)

     mvSetTrackDataFieldInfo

     This function sets the field information for a particular data chunk in a
     track.  The parameters are interpreted as follows:

     firstField contains the size of the first field

     gap contains the size of the gap between the first and the second field
     as written in the file

     secondField contains the size of the second field

     The function can fail under the following conditions:

     1. if track is invalid.  (error code: MV_BAD_ID) 2. if index is out of
     range. (error code: MV_PARAM_OUT_OF_RANGE) 3. if the data is not of image
     type or is not interlaced. (error code:  MV_INVALID_DATA_TYPE)

     Once this information is set it is available for all movie file formats
     at run time.  Since the information is only saved out to QuickTime files
     you must ensure that the movie is a QuickTime movie if you wish to
     retrieve the information after the file has been closed.


SEE ALSO
     mvReadTrackDataFields(3dm), mvInsertTrackDataFields(3dm).