mvReadTrackDataFields(3dm)			    mvReadTrackDataFields(3dm)

NAME    [Toc]    [Back]

     mvReadTrackDataFields, mvInsertTrackDataFields - read and insert field
     based data

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/moviefile.h>


     DMstatus mvReadTrackDataFields( MVid track, int index,
			       size_t sizeFirstField, void *bufFirstField,
			       size_t sizeSecondField, void *bufSecondField );

     DMstatus mvInsertTrackDataFields( MVid track,
			      MVtime time, MVduration duration,
			      MVtimescale timeScale,
			      size_t sizeFirstField, void *bufFirstField,
			      size_t sizeSecondField, void *bufSecondField,
			      MVdatatype datatype, int paramsId	);

DESCRIPTION    [Toc]    [Back]

     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 area to describe	the sizes and relative positions of these
     fields.  When field information is	available, mvReadTrackDataFields can
     be	used to	read each field	into its own buffer.  mvInsertTrackDataFields
     may be used to insert field data in separate buffers into a track.	 This
     feature is	only fully supported for QuickTime files.

     mvReadTrackDataFields

     This function fetches a data chunk	and reads the data into	the 2 buffers,
     one field in each buffer.	The function must be called with a valid track
     in	track.	sizeFirstField should contain the size of the buffer pointed
     to	by bufFirstfield.  sizeSecondField should contain the size of the
     buffer pointed to by bufSecondField.

     If	the function succeeds, DM_SUCCESS is returned and:

     bufFirstField will	contain	the bytes corresponding	to the first field of
     the data chunk

     bufSecondField will contain the bytes corresponding to the	second field
     of	the data chunk

     The function can fail under the following circumstances:

     1.	track id is invalid (error code: MV_BAD_ID) 2. 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. the track
     data cannot be parsed as 2	separate fields	(error code:
     MV_INFO_NOT_AVAILABLE) 5. the sizes of the	buffers	are not	big enough to



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mvReadTrackDataFields(3dm)			    mvReadTrackDataFields(3dm)



     hold the data (error code:	MV_BUFFER_TOO_SMALL)

     mvInsertTrackDataFields

     This function inserts 2 fields of data into a track for a given time and
     duration.

     The function must be callsed with a valid track.  The other parameters
     are interpreted as	follows:

     time is the time at which the new segment is to be	inserted.  If the time
     specified is beyond the duration of the track, an empty segment will
     first be inserted to cover	the time between the duration of the track and
     the time specified.

     duration is the duration for which	the inserted segment is	to last.

     timescale is the timescale	for time and duration.

     sizeFirstField contains the size of valid data pointed to by
     bufFirstField.

     bufFirstField contains the	bytes corresponding to the first field to be
     inserted into the movie file.  The	data must be of	the same format
     described by the parameters indexed by paramsId.

     sizeSecondField contains the size of valid	data pointed to	by
     bufSecondField.

     bufSecondField contains the bytes corresponding to	the second field to be
     inserted into the movie file.  The	data must be of	the same format
     described by the parameters indexed by paramsId.

     dataType contains the datatype of the chunk that is being passed in.
     Currently,	this bit mask is only used to indicate whether the chunk is a
     key frame or not, and valid types are MV_FRAMETYPE_DELTA (for delta
     frames) and MV_FRAMETYPE_KEY (for key frames).  All uncompressed frames
     or	compressed frames from a compression scheme that is not	key-frame
     based are considered key frames.

     paramsId is the index of the parameter returned by	mvAddTrackDataParams.
     The default index is 0, which is the index	of the params introduced by
     mvAddTrack.  If this parameter is out of range of the valid data params,
     an	error is set and DM_FAILURE is returned.  The field
     DM_IMAGE_INTERLACING in the DMparams pointed to by	paramsId must one of
     DM_IMAGE_INTERLACED_ODD or	DM_IMAGE_INTERLACED_EVEN.

SEE ALSO    [Toc]    [Back]

     mvGetTrackDataFieldInfo(3dm), mvSetTrackDataFieldInfo(3dm),
     mvTrackDataHasFieldInfo(3dm), mvReadTrackData(3dm),
     mvInsertTrackData(3dm).



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mvReadTrackDataFields(3dm)			    mvReadTrackDataFields(3dm)


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