Using Help | Contents | Index Back 310
Adobe Premiere Pro Help Producing Final Video
Using Help | Contents | Index Back 310
DVD production
The data rate should maximize quality while fitting the entire program
within the space available on the DVD. In Adobe Premiere Pro, by default the DVD data
rate is automatically adjusted by the Adobe Media Encoder, which is used by the Export >
Export to DVD command.
Non-DV videotape production
The data rate should fall within the capabilities of the
computer and hard disk that performs the final playback to tape.
Hard-disk playback
If your final video will be played back from a hard disk, determine
the typical data transfer rate of your audience’s hard disks and set the data rate
accordingly.
If you are exporting video to be used in another editing system, or to be imported
into a compositing application such as Adobe After Effects, you’ll want to export at the
maximum quality. Use a lossless codec or the codec supported by your video capture
card,
and specify the data rate that the editing system supports for video capture and editing.
CD-ROM playback
The data rate for video played from a CD-ROM depends on the speed
of the drive. For example, if you are preparing a final video file for a double-speed CD-
ROM
drive (300 kilobytes per second) you might specify between 150 kilobytes and
200 kilobytes per second to account for both the data rate of the drive and for the system
overhead required to move the data.
Intranet playback
The data rate can be 100 kilobits per second or faster, depending on
the speed of your
intranet
. An intranet is an in-house or private network that uses Internet
network protocols. Because they are limited in scope, intranets generally use higherquality
communications lines than standard telephone lines, so they are usually much
faster than the Internet.
Streaming video over the World Wide Web
The data rate should account for real-world
performance at the target data rate. For example, the data rate for streaming video
designed for a 56-kilobit-per-second connection is often set to 40 kilobits per second.
That’s because factors such as data volume and line quality often prevent telephonebased
Internet connections from consistently achieving their stated data rate.
Downloading a video file over the World Wide Web
The data rate is less important
than the size of the video file on disk, because the main concern is how long it takes to
download the file. However, it still may be desirable to reduce the data rate for
downloaded video because doing so reduces the size of the video file, making it
download faster.
Use the Get Properties For command to analyze the data rate of files you export. See
“Analyzing clip properties and data rate” on page 89.
About compression keyframes
Compression keyframes are different from the keyframes that you use to control track or
clip properties such as audio volume or clip rotation. Compression keyframes are
automatically placed during export at regular intervals in the movie. During compression,
they are stored as complete frames. The frames between the keyframes, called
intermediate
frames, are compared to the previous frame and only the changed data is stored.
This process can greatly reduce file size, depending on the spacing of the keyframes.
Fewer keyframes and more intermediate frames result in smaller file sizes but produce
lower-quality images and playback. More keyframes and fewer intermediate frames result
in significantly larger file sizes but produce higher-quality images and playback.
