Importing digital audio

You can import digital audio clips stored as audio files or tracks in video files. Digital audio is stored on computer hard disks, audio CDs, or digital audio tape (DAT) as binary data readable by computers. To keep quality as high as possible, transfer digital audio files to your computer via digital connections. Avoid digitizing the analog outputs from your audio sources through your sound card.

You can use CD audio (CDA) files in a project, but before you can import them into Premiere Pro, you need to convert them to a supported file format, such as WAV or AIFF. You can convert CDA files using an audio application such as Adobe® Audition®.

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 Audition

You can use Adobe Audition to perform advanced audio editing. If you export the audio from Adobe Audition 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.

• Premiere Pro does conform audio in uncompressed formats that were not recorded in a natively supported sample rate. In most of these cases, it will upsample the audio either to the nearest supported sample rate, or to a supported sample rate that is an even multiple of the source audio sample rate. For example, it will upsample an 11024Hz source to 11025Hz, since that is the nearest supported rate, and there is no supported rate that is an even multiple of 11024.

Compressed audio

• Premiere Pro does conform all compressed audio, such as audio found in mp3, WMA, MPEG, or compressed MOV files. It conforms this audio at the sample rate of its source file. For example it will conform a 44100Hz mp3 file at 44100Hz. However, if the conformed audio is used in a sequence with a non-matching sampling rate, as when a 44100Hz clip is used in a 44000Hz sequence, the audio will play back at the sample rate of the sequence without further conforming.

Premiere Pro does not conform a file that was conformed in one sequence when you import it into another sequence with the same audio sample rate, so long as you haven’t moved or renamed the file since it was conformed. Premiere Pro keeps the location of the conform files for all files it has conformed in the Media Cache Database.

In addition to conforming some files, Premiere Pro also creates a PEK file for any file containing audio when it is first imported into a project. It uses these PEK files for drawing the audio waveforms in Timeline panels. Premiere Pro stores PEK files in the location specified for Media Cache Files through the Media pane of the Preferences dialog box.