Progressive downloading lets you use ActionScript to load external FLV files into a SWF file, and play them back at runtime. To initiate playback of the FLV file, and to control the Play, Pause, and Seek behaviors, as well as the buffer time and size for a given video file, use the netConnection and netStream objects.

Because the video content is kept external to the other Flash content and the video playback controls, it’s relatively easy to update video content without republishing the SWF file.

Progressive downloading provides the following advantages over embedded video:

• During authoring, publish only the SWF interface to preview or test part or all of your Flash content. This results in faster preview times and quicker turnaround on iterative experimentation.

• During delivery, video begins playing as soon as the first segment is downloaded and cached to the local computer’s disk drive.

• At runtime, video files are loaded from the computer’s disk drive into the SWF file, with no limitation on file size or duration. No audio synchronization issues or memory restrictions exist.

• The frame rate of the video file can be different from the frame rate of the SWF file, allowing for greater flexibility in authoring your Flash content.