MACROMEDIA FLASH MX 2004-USING FLASH Use Manual page 180

Tips for creating Flash video with Sorenson Spark
How you compress your video is largely determined by the content of the video. A video clip of a
talking head with little action and only short bursts of moderate motion compresses differently
than footage of a soccer match. The following tips discuss delivering the best possible Flash video:
Strive for simplicity
final compressed video look "chunky" during the change. Hard cuts or quick cross-fades are
usually best. Video sequences that show an object zooming from behind the first track, doing a
"page turn," or wrapping around a ball and then flying off the screen can be eye-catching, but
they usually don't compress well and should be used sparingly.
Know your audience data rate
files at lower data rates. Users with fast Internet connections can view the files with little or no
wait, but dialup users must wait for files to download. It is best to make the clips short to keep the
download times within acceptable limits for dialup users.
Select the proper frame rate
If you have a higher data rate clip, a lower frame rate can improve playback on lower-end
computers. For example, if you are compressing a talking head clip with little motion, cutting
the frame rate in half will probably save you only 20% of the data rate. However, if you are
compressing high-motion video, reducing the frame rate has a much greater effect on the
data rate.
Because video looks much better at native frame rates, Macromedia recommends leaving it high if
allowed by your delivery channels and playback platforms. However, if you need to reduce the
frame rate, the best results come from dividing the frame rate by whole numbers.
Select a frame size that fits your data rate
document is important for producing high-quality video. At a given data rate (connection speed),
increasing the frame size results in decreased video quality. When you select the frame size for
your document, you must consider frame rate, source material, and personal preferences. The
following list of common frame sizes can be used as a guideline. You can experiment to find the
best setting for your project.
•
Modem: 160 x 120
•
Dual ISDN: 192 x 144
•
T1/DSL/cable: 320 x 240
Know progressive download
video. While your video clip downloads, you might want to have other content that appears and
"disguises" the download. For short clips, you can use the following formula: Pause = download
time – play time + 10% of play time. For example, If your clip is 30 seconds long and it takes one
minute to download, you should give your clip a 33-second buffer: 60 seconds – 30 seconds + 3
seconds = 33 seconds.
180 Chapter 10: Working with Video
Avoid elaborate transitions—they don't compress well and can make your
When you deliver video over the Internet, you should produce
Frame rate indicates how many frames play each second (fps).
You should know how long it is going to take to download your
As with the frame rate, the frame size for your