• set background to black fill
• set margins to zero
• set width to 25.4cm (change later as you experiment)
• set height to 50cm for starters
• put 10-20 blank lines at top of page
• create a table with 10-20 rows and 1 column, turn off borders, set spacing to say 5 pixels
• populate table with credits as you want them to appear
• expand page height as needed, so there's lots of space above and below the table
• export the document as a pdf

Convert in GIMP to a transparent PNG file

• import the PDF into GIMP
• accept the PDF import settings
• save as a PNG file
• duplicate the layer, and delete old one
• use eyedropper to select black background
• use color select tool to select black background
• do edit-cut to remove black background
• you should now see white text on transparent background
• save the png file again

Cinelerra Import (cinelerra project file) (final rendered video)

• start up Cinelerra
• create new video track, set the track width to the width of the gimp image, arm this track and disarm all others
• import the png file and place it on the new video track
• stretch it along the timeline to required length
• go to frame 1 and turn on auto keyframes
• camera-pan in y direction until credits are just below the frame, make sure x camera value is 0
• go to frame n-1
• camera-pan in y direction until credits are just above the frame, make sure x camera value is 0
• turn off auto keyframes
• render out the video