MACROMEDIA FLASH MX 2004-USING ACTIONSCRIPT IN FLASH Use Manual page 112

Note: Remember to delete the FLV file from your Flash document and library if you intend to
dynamically load the video into that document at runtime.
Flash MX Professional includes an external FLV Exporter that compresses video from third-party
video editing software such as QuickTime Pro and Adobe After Effects. The quality of the FLV
file that is created using this tool is better than video exported directly from Flash.
When you compress video, remember the following recommendations:
Do not recompress video
Recompressing video leads to quality degradation, such as artifacts.
Try to use raw footage or the least compressed footage that is available to you.
Make your video as short as possible
Trim the beginning and end of your video so it is as
short as possible, and edit your video to remove any unnecessary content. This can be
accomplished directly in Flash using the Video Import wizard.
Adjust your compression settings If you compress footage and it looks great, try changing
your settings to reduce the file size. Test your footage, and modify it until you find the best setting
possible for the video you are compressing. Remember that all video has varying attributes that
affect compression and file size; each video needs its own setting for the best results.
Limit effects and rapid movement Limit movement as much as possible if you are concerned
about file size. Any kind of movement, particularly with many colors, increases file size. For
example, effects (such as cross fades, blurs, and so on) increase file size, because the video contains
more information.
Choose appropriate dimensions
If your target audience has a slow Internet connection (such
as phone modems), you should make the dimensions of your video smaller, such as 160x120
pixels. If your visitors have fast connections, you can make your dimensions larger (for example,
320x240 pixels).
Choose appropriate frames per second Choose an appropriate number of frames per second
(fps). If your target audience has slow Internet connections (such as phone modems), you should
choose a low rate of frames per second (such as 7 or 15 fps). If your visitors have fast connections,
you can use a higher rate of frames per second (such as 15 or 30 fps). You should always choose a
frames per second that is a multiple of your original frame rate. For example, if your original
frame rate was 30 fps, you should compress to 15 fps or 7.5 fps.
Choose an appropriate number of keyframes Video keyframes are different from keyframes
in Flash. Each keyframe is a frame that draws when the video is compressed, so the more frequent
your keyframes are the better quality the footage will be. More keyframes also mean a higher file
size. If you choose 30, a video keyframe draws every 30 frames. If you choose 15, the quality is
higher because a keyframe draws ever 15 frames and the pixels in your footage are more accurate
to the original.
Reduce noise
Noise (scattered pixels in your footage) increases file size. Try reducing noise
using your video editor, to reduce the video file size. Using more solid colors in your video reduces
its file size.
112 Chapter 3: Using Best Practices