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  "title" : "Creating video tracks at 29.97 frames per second"
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# Creating video tracks at 29.97 frames per second

Configure your time-to-sample atom for 29.97 frames per second.

## Overview

NTSC color video is not `30` frames per second (fps), but actually `29.97` fps. The previous example showed how the media time scale and the duration of the frames specify the video’s frame rate. By setting the media’s time scale to `2997` units per second and setting the frame durations to `100` units each, the effective rate is `29.97` fps exactly.

In this situation, it is also a good idea to set the movie time scale to `2997` in order to avoid movie edits that don’t land on frame boundaries. The movie’s time scale is stored in the movie header atom.

With a time scale of `2997` in the media header atom, the time-to-sample atom would contain the data values listed in following table.

|Field            |Value   |
|-----------------|--------|
|Atom size        |`24`    |
|Atom type        |`'stts'`|
|Version/Flags    |`0`     |
|Number of entries|`1`     |
|Sample count     |`n`     |
|Sample duration  |`100`   |

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