Appendix 1

Appendix 2
Understanding the PAL
Video Format
Jaime Estrada-Torres, London Film School
The Phase Alternate Line (PAL) color encoding system scans images into 625 horizontal lines to
form a video frame every 1 /25 of a second. There are 2 fi elds per each video frame, which results in
50 fi elds for every 25 frames in each second. It is also possible to telecine with 2-2-2-2-2-2-2-2-2-2-
2-3 cadence to produce video that plays without speed change, but at the cost of the one-to-one
relationship between timecode and key code, as seen in Figure A2.1. This would, therefore, be inappropriate
for a fi lm edit, but may be used for video fi nish projects. The PAL system allows for a more
defi ned color rendition than that of an NTSC image.
The burning, on the bottom left of frame in Figure A2.1, shows fi lm key numbers, (new footage
updates on the twentieth frame). The burning on the right shows 25 FPS time code (new, second
updates on the twenty-fi fth frame). A specifi c time code identifi es a specifi c frame on the tape, in the
same way that a particular key number relates to a particular fi lm frame on the fi lm negative/print.
Film shot at 24 FPS runs 4.1 percent faster during PAL telecine. This process creates a one-to-one
correspondence between the fi lm and video frames as illustrated in Figure A2.2. Each fi lm frame
makes up the two fi elds that constitute the standard PAL video frame.
Note that the recommended PAL route for fi lm shot at 24 FPS is to telecine with the fi lm running at
25 FPS. The Final Cut setting for the corresponding project must be set as follows: transfer at 25,
and video time code at 25.
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