Macromedia flash 8-using flash video encoder Manual De Usuario

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8
Using Flash Video Encoder
It’s important to note that interframe codecs also use intraframes. Intraframes are used as the 
reference frames (keyframes) for the interframes. Both the On2 VP6 and Sorenson Spark 
codecs always begin with a keyframe. Each keyframe becomes the main reference frame for 
the following interframes. Whenever the next frame is significantly different from the 
previous frame, the codec compresses a new keyframe.
Comparing the On2 VP6 and Sorenson Spark video 
codecs
The On2 VP6 codec is the default video codec to use when encoding FLV content for use 
with Flash Player 8. Using the On2 VP6 codec provides the following advantages when 
compared to the Sorenson Spark codec:
Encodes higher quality video at the same data rate 
Supports the use of an alpha channel to create composite video
In order to support better quality video at the same data rate, the On2 VP6 codec is 
noticeably slower to encode, and requires more processor power on the client computer to 
decode and play back the video data. For this reason, you should consider the lowest common 
denominator of computer that your audience will use when they access your Flash video 
content. 
If you anticipate a large user base that is using older computers, it may be advisable to 
consider encoding your FLV files using the Sorenson Spark codec.
Understanding video standards and 
terminology
The following section introduces digital video concepts and terminology you should know 
when working with video content. If you are new to digital video or want to learn more about 
digital video and encoding high-quality video content, this section can help you understand 
the trade-offs related to encoding video for different applications and Internet viewing 
environments.
000_FLVEncoder.book  Page 8  Friday, August 12, 2005  3:50 PM