Common Audio Formats settings in Compressor
Four built-in settings in Compressor use the Common Audio Formats transcoding format: AIFF File (Audio Interchange File Format), CAF File (Apple Core Audio Format), FLAC File (Free Lossless Audio Codec), and WAVE File (Waveform Audio File Format).
Note: You can also create custom settings that use the Common Audio Formats transcoding format. However, the built-in settings (in the Settings pane) analyze your source media and assign optimal properties to ensure the best possible transcoding results.
The properties of built-in and custom settings that use this transcoding format are located in the General inspector and Audio inspector (described below).
Displays the setting name and transcoding format, as well as an estimated output file size. When you add a setting to a job or change the setting’s properties, this summary is automatically updated.
Name: Displays the name of the setting.
Description: Displays the description of the setting.
Extension: Displays the extension of the output file (.aiff, .caf, .flac, or .wav).
Tip: To output a file with a different extension, change the value in the “File type” pop-up menu, described below.
Allow job segmenting: This checkbox is dimmed because job segmenting is not available for settings that output only an audio file.
Default location: Choose an item from the pop-up menu to set the default save location for transcoded files.
File type: Choose a file type from the pop-up menu (AIFF, CAF, FLAC, or WAVE).
Sets the processing algorithm used to adjust the frame rate during transcoding. Select one of the following options:
Set to percent of source using: Modifies the output clip’s speed by a percentage of the source clip’s speed. Enter a value in the percentage field or choose a preset value from the adjacent pop-up menu (with a down arrow).
Set to: Sets the duration of the clip. Enter a timecode duration in the field or click the arrows to increase or decrease the time.
So source frames play at [frame rate] fps: Nondestructively changes the playback speed of the clip without discarding frames or creating new frames. This property has no effect unless the “Frame rate” value in the Video inspector is different from the source file’s frame rate. For example, if you add a 10-second source file with a frame rate of 24 fps to Compressor, set the “Frame rate” property in the Video inspector to 25 fps, and then select “So source frames play at 25 fps” in the General inspector, the resulting duration of the transcoded clip (at 25 fps) will be 9 seconds and 15 frames.
For more information, see Retime video and audio using Compressor.
Channel layout: Use this pop-up menu to manually set the type of audio channel layout. For more information about audio channel layouts, including the surround sound channel layout, see Audio channel layouts in Compressor.
Sample rate: Use this pop-up menu to set the number of times per second that music waveforms (samples) are captured digitally. The higher the sample rate, the higher the audio quality and the larger the file size.
Sample size: Use this pop-up menu to manually set the sample size of the audio signal.
Format: Use this pop-up menu to set the format of the audio output.
Quality: Use this pop-up menu to select the quality of the audio output.
Bit rate: Use this pop-up menu to set the bit rate for the encoded audio.
Bit rate strategy: Use this pop-up menu to select the strategy used to encode the audio. There are four options:
Constant bit rate: Uses the value set in “Bit rate” to determine the bit rate for the encoded audio.
Average bit rate: Uses the value set in “Bit rate” to determine the target average bit rate for the encoded audio. This option provides a more consistent bit rate than variable bit rate.
Variable bit rate constrained: Uses the value set in “Bit rate” to determine the maximum bit rate for the encoded audio.
Variable bit rate: Encodes the audio using a variable bit rate determined by Compressor.
Compression: Use this pop-up menu to manually set the amount of compression the FLAC encoder uses to encode the audio signal. This setting is only available for FLAC file types.
For a list of available audio effects and instructions on how to add an audio effect to a setting, see Add and remove effects in Compressor.
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