Adobe Premiere Pro CS4 - Manual (Page 100)

94 USING ADOBE PREMIERE PRO CS4
Capturing, digitizing, transferring, and importing
Last updated 11/6/2011
Using compressed audio formats
Music stored in formats such as MP3 and WMA are compressed using a method that removes some of the original
audio quality. To play back compressed audio, Premiere Pro must decompress the file and may need to resample it to
match your output settings. Although Premiere Pro uses a high-quality resampler for this purpose, the best results
come from using an uncompressed or CD audio version of the audio clip whenever possible.
Using audio from Adobe Soundbooth
You can use Adobe® Soundbooth™ CS4 to perform advanced audio editing. If you export the audio from Adobe
Soundbooth to an audio file format compatible with Premiere Pro, you can import the audio into Premiere Pro
projects.
Audio sample rates supported
Premiere Pro natively supports these audio sample rates:
• 8000 Hz
• 11025 Hz
• 22050 Hz
• 32000 Hz
• 44100 Hz
• 48000 Hz
• 96000 Hz
Conforming audio
Premiere Pro processes each audio channel, including audio channels in video clips, as 32-bit floating-point data at the
sequence sample rate. This processing assures maximum editing performance and audio quality. Premiere Pro
conforms certain types of audio to match the 32-bit format and the sequence sample rate. If conforming is required, it
is done when a file is imported into a project for the first time. Conforming takes some time and disk space. A progress
bar appears at the lower right of the Premiere Pro window when conforming begins. Premiere Pro saves conformed
audio in CFA audio preview files. You can determine where to save these audio preview files by specifying a Scratch
Disk location for Audio Previews in the Project Settings dialog box.
You can work with audio files, even applying effects to them, before they are fully conformed. However, you can
preview only the parts of the files that have been conformed. You cannot hear unconformed sections on playback.
These rules determine which types of audio get conformed:
Uncompressed audio
• Premiere Pro does not conform audio in uncompressed clips that were recorded in one of the natively supported
sample rates, when you use these clips in sequences with matching sample rates.
• Premiere Pro does conform audio in uncompressed clips when you use them in sequences with non-matching
sample rates. However no conforming is done until you export the sequences or create audio preview files.