FLASH CS3
User Guide
471
Trim the beginning and end of your video, 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. 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 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), 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 (fps).
If you target users that typically have older computer processors, choose a low rate of frames per second (such as 7
or 15 fps). If you target users with newer computers, you can use a higher rate of frames per second (such as 15 or
30 fps). Always choose an fps that is a multiple of your original frame rate. For example, if your original frame rate
was 30 fps, 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 is. More keyframes also mean a
larger 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. Reduce noise using your video editor, to reduce the video
file size. Using more solid colors in your video reduces its file size.
When you put FLV files on a server, they use the
video/x-flv FLV mime type
. If you have difficulty viewing FLV
files after you upload your files, check that this mime type is set on your server. FLV files are binary, and some appli-
cations that you build might require that the
application/octet-stream
subtype is also set. For more information
on the Flash Player specifications, see
www.adobe.com/go/flashfileformat
.
Troubleshooting video
You can create an application and then encounter problems after you upload it to your server.
•
Check that your Flash Player version is correct.
For example, if you encoded your files using On2 codec, you need Flash Player 8 or later installed for the browsers
you use to view your Flash content.
Note:
For Flash Player and FLV compatibility, see About using FLV video in Learning ActionScript 2.0 in Adobe Flash.
•
Check that your server supports the FLV mime type. For more information on FLV files on a server, see Config-
uring your server for FLV files in
Learning ActionScript 2.0 in Adobe Flash
.
