Recording for Playback on NTSC and PAL Video

Both NTSC and PAL television systems use interlaced video. This means that each frame actually consists of two fields. Each field contains half of the frame scan lines, and only a single field is refreshed in each scan. An NTSC screen that displays 30 frames per second will therefore display 60 fields per second.

When recording a script, you now have the option to render each frame in two passes, with the second pass half a frame ahead of the first one, and then interlace the images from the two passes such that the resulting frame matches the field refresh rate of the display system. This technique, known as field rendering, effectively doubles the apparent refresh rate of the recorded sequence, from 30 to 60 fields for NTSC and from 25 to 50 fields for PAL.

1. In the Record Script dialog box, turn on Field Rendering.


2. If appropriate, turn on Odd Rows First. This setting determines whether the odd rows are taken from the first or second rendering pass. (This is sometimes referred to as “2:1” or “1:2” interlacing.) Most video recording equipment expects the even row first, so Odd Rows First is turned off by default. If this setting is incorrect, a field rendered movie will jump badly and appear worse than if field rendering was not used.

Field rendering is only useful when creating sequences that are to be played back on interlaced equipment (such as NTSC or PAL video). Field rendered sequences will not appear correct when played back with the MicroStation Movies utility (Utilities > Image > Movies) or other systems that do not refresh the interlaced fields separately.