Using Video in Flash

The pdf file available at http://www.ericd.net/pdfs/fmxb_ch18.pdf
and is saved on Comp desktop . Summary given below

Earlier external video files were linked to the Flash document. Flash did not store the actual video content. So you still needed an external player for playback.

Now it is possible to embed the video file in the Flash document (.fla file) as well as the Flash movie (.swf file).So no external player is required for playback.

Tips for using video well

1. Garbage in Garbage out. Use good quality video and audio clips.

2. Bring only finished video clips into Flash MX. Don't edit clips here. Flash is not designed for editing.

3. Minimise cross-fades and slow dissolves, which involve rapid changes to each frame.

4. Minimize duration. Don't use very long clips.

5. Use named anchors to let the user jump between scenes in a movie.

Compression of video files

Flash MX can import a wide variety of video file formats, including .mov, .avi, .dv, .wmv, .asf, and .mpg files. and compress them significantly.

How does compression take place ?

1. By comparing the data between each frame and by storing only the differences between the two.

2.By compressing data in each frame.

Flash throws out some color and detail information to cut file size. For example, if the original video source shows a sunset with 80 shades of orange, flash will show only 50 shades.

WHile importing the movie, flash creates a number of key frames and uses interframe and intraframe compression to reduce file size. More jerks in the movie = more keyframes=more file size.

Flash MX encodes video with the Sorenson Spark Basic edition codec, which uses CBR (constant bit rate) encoding. You have limited control over the compression options in Flash MX. ( VBR codec can be bought separately)

After embedding video, it becomes an embedded Video object in the Library. You can reuse the same Embedded Video object as several instances throughout the Flash document with no increase in file
size.

Macromedia Flash movies do not stream into the Flash Player. They download progressively. Video streaming, means that the video file is never downloaded as one single file to the end-user. Rather, a streaming video server delivers the video in realtime, sending the video frame by frame to the player.

A progressive download, on the other hand, is downloaded to the player. as a single file. However, the term progressive means that the video can start playback as soon as a certain percent of the video has downloaded into the player.