User Manual

Outputting Drop-Frame and Non-Drop-Frame Timecode Simultaneously for Downstream Encoding

1079

Outputting Drop-Frame and Non-Drop-Frame

Timecode Simultaneously for Downstream Encoding

You can output drop-frame and non-drop-frame NTSC timecode simultaneously from a 23.976,

24p, or 25p project. A broadcast production company might need to output drop-frame timecode

for a broadcast master while outputting non-drop-frame timecode to track NTSC film pulldown.

Tracking the pulldown is important because some networks require the 2:3 pulldown phase to be

inserted in the VITC (vertical interval timecode). Inserting the pulldown phase enables

downstream encoding of various compression formats (like MPEG-2) to be faster and of higher

quality.

For information about 2:3 pulldown, see “Transfer of 24-fps Film to NTSC Video” on

page 1503.

It is easy to track pulldown information within non-drop-frame timecode, because the

relationship stays the same for the length of the digital cut. Your Avid editing application can use

LTC to output the non-drop-frame timecode. See “Using LTC Timecode for Output” on

page 1041.

To output drop-frame and non-drop-frame timecode simultaneously for downstream

encoding:

1. Select Output > Digital Cut.

2. Do the following:

t Click the RS-422 Output menu, and select Drop.

t Click the LTC Output menu, and select Non-Drop.

Indicating the Destination Timecode Rate

When you select 24 (NTSC) as your output format, the Destination Timecode Rate menu

(labeled Dest. TC Rate) opens. Select a timecode rate that matches the timecode rate of the

recording device, such as a DAT deck.

If you select 29.97 fps as your Dest. TC Rate, the sequence duration displayed in the Timecode

Duration display of the Digital Cut tool is slightly shorter than the duration shown in the

Timeline. This shorter duration occurs because the video play rate is sped up in comparison with

the audio timecode rate. If you select 30.00 fps, the sequence duration in the Digital Cut tool

matches the sequence duration in the Timeline.

The value you select also sets the rate for LTC output, if any, without changing the play rate of

the media being output (24 NTSC).