Autodesk 64006-051108-9001 User Guide - Page 192

Compare Uncompressed Frames, Video Data Rate, Set the Video Data Rate, Factors that Limit Data Rate

Page 192 highlights

184 Chapter 8: Encoding You can manually specify points at which you want a keyframe using the EventStream editor. This is useful if you know a movie is to be accessed at a particular point. For information on setting manual keyframes, see "Keyframe" on page 223. Compare Uncompressed Frames The Compare Uncompressed Frames option determines whether or not the codec looks at the previous compressed or previous uncompressed frame to generate each new delta frame. If you are working with computer-generated images, such as 3D animation, enabling the Compare Uncompressed Frames option may give you better results in certain cases. You may also get better results using this option with bluescreen movies that have still images as the background. For live-action video, leave this feature disabled. Note: This feature can significantly degrade the movie's image quality. If you want to use the Compare Uncompressed Frames option, always run tests with it on and with it off to determine the optimal setting for the material. Never assume it will produce better results. Video Data Rate One of the most important decisions you must make when preparing movies is choosing the data rate. More than any other factor, the data rate affects the final image and sound quality of your movie. It also affects the size of the final file, as well as the playback method for effectively delivering the movie. Set the Video Data Rate 1. Determine the data rate for your movie. 2. Choose the method of data rate control from the Video Data Rate menu. 3. Type the desired data rate in the Limit to field. 4. Set the unit of measure menu to: •kbits/sec or kBytes/sec - if you are limiting the data rate. •Total KBytes or Total MBytes - if you are limiting the total size of the file, not the data rate. Factors that Limit Data Rate Usually there are three factors that dictate the data rate you can use on a movie: •The media or connection speed. •The amount of video you need to fit into your disc or file. •The speed of the minimum target computer.

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Chapter 8: Encoding
184
You can manually specify points at which you want a keyframe using the EventStream editor.
This is useful if you know a movie is to be accessed at a particular point. For information on
setting manual keyframes, see “Keyframe” on page 223.
Compare Uncompressed Frames
The Compare Uncompressed Frames option determines whether or not the codec looks at the
previous compressed or previous uncompressed frame to generate each new delta frame.
If you are working with computer-generated images, such as 3D animation, enabling the
Compare Uncompressed Frames option may give you better results in certain cases. You may
also get better results using this option with bluescreen movies that have still images as the
background. For live-action video, leave this feature disabled.
Note:
This feature can significantly degrade the movie’s image quality. If you want to use the
Compare Uncompressed Frames option, always run tests with it on and with it off to
determine the optimal setting for the material. Never assume it will produce better results.
Video Data Rate
One of the most important decisions you must make when preparing movies is choosing the
data rate. More than any other factor, the data rate affects the final image and sound quality of
your movie. It also affects the size of the final file, as well as the playback method for effectively
delivering the movie.
Set the Video Data Rate
1.
Determine the data rate for your movie.
2.
Choose the method of data rate control from the Video Data Rate menu.
3.
Type the desired data rate in the Limit to field.
4.
Set the unit of measure menu to:
kbits/sec
or
kBytes/sec
— if you are limiting the data rate.
Total KBytes
or
Total MBytes
— if you are limiting the total size of the file, not the data
rate.
Factors that Limit Data Rate
Usually there are three factors that dictate the data rate you can use on a movie:
The media or connection speed.
The amount of video you need to fit into your disc or file.
The speed of the minimum target computer.