4.1

Chapter 5 Advanced tasks 73
Change the frame rate for a transcoded le
1 Select a setting that is part of a job in the batch area, or select a custom setting in the
Settings pane.
2 In the Video inspector, do one of the following:
•
Choose an item from the “Frame rate” pop-up menu.
Automatic, the default setting, matches the frame rate of the transcoded le to that of
the source le. You can also choose any of several commonly used frame rates, including
23.976 fps, 24 fps, and so on.
•
Type a custom frame rate into the eld to the right of the pop-up menu.
Note: Frame rate conversion can have a subtle or dramatic eect depending on how big a
dierence there is between the original and new frame rates, and also depending on the specic
nature of the footage being converted. Footage with a lot of movement yields a much more
visible change than footage with little movement in the frame. Frame rate conversion may also
add visible artifacts in the transcoded le; from stuttering (sometimes called “juddery”) playback,
to repeated frames, ghost images, or other unnatural-looking elements. These eects can be
somewhat mitigated by adjusting the “Retiming quality” property in the Quality section of the
Video inspector.
3 Select a value from the “Field order” pop-up menu to choose a progressive or interlaced frame rate.
If the current setting does not allow eld order modication, this control remains dimmed.
If you want to convert a le with an interlaced format into a progressive format, see About
deinterlacing on page 73.
Note: The properties in the Retiming section of the General inspector are always aected by the
“Frame rate” property, as well as the “Retiming quality” property in the Video inspector.
About deinterlacing
Video to be played on traditional NTSC or PAL televisions is encoded using an interlaced frame rate.
Each frame is actually made up of two half-frames called elds. Each eld contains half the frame
lines; the odd (or upper) eld contains lines 1, 3, 5, 7, 9 and so on, and the even (or lower) eld
contains lines 2, 4, 6, 8, 10, and so on. When the video is played back, the TV displays the elds in
an alternating pattern, which creates an eective illusion of smooth movement. Viewing interlaced
video on a computer screen that displays both elds simultaneously may reveal a combing eect.
Interlacing creates
a “comb” effect
when viewed on
a computer screen.
67% resize factor