Embedded video clips are compressed upon import into a Macromedia Flash document. You choose compression options in the Import Video Settings dialog box. The dialog box also contains information about the source video being imported, as well as the output properties of the compressed video.

 
Compression options
The compression options in the Import Video Settings dialog box are discussed below.

Quality
This setting controls the overall image quality of the exported video. The value you specify determines the degree of spatial compression applied upon import. Higher values result in less spatial compression (better image quality), lower values result in more compression (smaller file sizes).

Keyframe interval
The Keyframe Interval setting determines how frequently a full frame of the source video is preserved in the Timeline. For example, a Keyframe interval of 24 will insert a video keyframe every 24th frame in the Timeline. Each new keyframe is used as a reference point for any subsequent frame differences (interframes) that follow it.

Smaller interval values result in more keyframes, and a larger file size; larger intervals result in fewer keyframes and a smaller file size. A Keyframe interval of 0 adds a single keyframe at the beginning of the video stream and no other keyframes.

Low-motion video (such as a talking head) can look acceptable with a larger keyframe interval. Video with lots of quick changes will probably look best with a smaller Keyframe interval value.

The keyframe interval can also affect seek times, which is the time it takes to jump from one frame of video to another using ActionScript (for example, gotoAndPlay(200) ). If the frame being jumped to is not a keyframe (that is, an interframe), Flash Player must first decompress all the intermediate interframes to display that frame. Shorter keyframe intervals result in faster seek times, since there are fewer possible interframes to be decompressed.

Scale
Adjust this slider to shrink the video's dimensions proportionally.

Synchronize video to Flash document frame rate
When selected, this will match the playback rate of the imported video to the Flash document's frame rate. For instance, if the imported video clip has a faster frame rate than the Flash document, Macromedia Flash MX will drop frames from the video to synchronize the two playback rates. The duration of the imported video will match the duration of the source video.

When this option is deselected, Macromedia Flash MX assigns one frame of video to one frame in the Timeline. If the video clip has a faster frame rate than the Flash document, the imported video will playback slower than the original.

Number of video frames to encode per number of Flash frames
Select a value to specify the ratio of imported video frames to frames in the Timeline. For example, to play one imported video frame per one main Flash Timeline frame, choose 1:1; to play one imported video frame per every two main Timeline frames, choose 1:2; and so on.

Dropping frames from the imported video does not slow down the motion of the video. Instead, it displays fewer frames per second, so that the video appears more choppy in playback.

If you synchronize video that has a lower frame rate than the Flash movie, the option for dropping frames is disabled. You must deselect the Synchronize option in order to drop frames.

Import Audio
Select this option to include the audio track (if present) in the imported video clip. Deselect this option to omit the audio track from the imported video clip.

Unlike the video track, the sound track is imported in its raw (uncompressed) form and compressed during export to SWF. For more information, see Publishing Macromedia Flash movies with video.

Note: If the audio codec used in the audio track is not supported on your system, Flash displays a warning in the Import Video Settings dialog box. You can continue the procedure and import the video without sound, or return to the video authoring application and resave the video with an audio codec that is supported on your system.