When you store an image of your own format, you can also store a thumbnail, a miniature-sized version of the image. You control the size and format of the thumbnail. When you store an image in a format that the Image Extender recognizes, it automatically generates and stores a thumbnail for the object. The Image Extender creates a thumbnail in GIF format of size 112 x 84 pixels.
When you store a video object of your own format, you can also store a thumbnail that symbolizes the video object. When you store a video object in a format that the Video Extender recognizes, it automatically stores a generic thumbnail for the object. The Video Extender creates a thumbnail in GIF format of size 108 x 78 pixels.
If you don't want to store a thumbnail when you store an image or video object with user-supplied attributes, specify a null value or empty string in place of the thumbnail.
Generate the thumbnail in your program--the extenders do not provide APIs to generate thumbnails. Create a structure in your program for the thumbnail and specify the thumbnail structure in the UDF.
The following statements in a C application program store a row that includes a video clip in a database table. The source video clip, whose content is in a server file, has a user-defined format. The video content will remain in the server and be pointed to from the table. A thumbnail of a representative video frame is also stored.
EXEC SQL BEGIN DECLARE SECTION; long hvStorageType; struct { short len; char data[4000]; }hvVidattrs; struct { short len; char data[10000]; }hvThumbnail; EXEC SQL END DECLARE SECTION; MMDBVideoAttrs *pvideoAttr; hvStorageType=MMDB_STORAGE_TYPE_EXTERNAL; pvideoAttr=(MMDBVideoAttrs *) hvVidattrs.data; strcpy(pvideoAttr>cFormat,"Formatv"); hvVidattrs.len=sizeof(MMDBVideoAttrs); /* Generate thumbnail and assign data in video structure */ EXEC SQL INSERT INTO EMPLOYEE VALUES( '128557', 'Anita Jones', DB2VIDEO( CURRENT SERVER, '/employee/videos/ajones.vid', :hvStorageType, 'Anita''s video', :hvVidattrs, :hvThumbnail) /* Thumbnail*/ );