Audio properties of presets in Compressor
When you select a preset, its audio properties appear in the Audio inspector.
Important: Not all properties or options are available for all transcoding jobs. The options shown depend on the type of source media you’re transcoding, the preset’s format, the configuration of other properties, and the hardware and software you’re using.
Audio property | Preset formats | Description |
|---|---|---|
Enable audio pass-through | QuickTime Movie | Select this checkbox to copy the source audio to the destination file, without modification. |
Channel layout | All audio-enabled preset formats | Use this pop-up menu to manually set the type of audio channel layout. See Audio channel layouts. |
Sample rate | All audio-enabled preset formats | Use this pop-up menu to set the sample rate of the transcoded audio. |
Sample size | All audio-enabled preset formats | Use this pop-up menu to manually set the sample size of the audio signal. |
Codec | QuickTime Movie | Use this pop-up menu to choose an audio codec. |
Sample format | QuickTime Movie | When the audio Codec property is set to Linear PCM, use this pop-up menu to select whether to output your audio in Big Endian or Little Endian format. |
Format | MPEG-4 | Use this pop-up menu to choose an MPEG-4 Advanced Audio Coding (AAC) or Apple Lossless format for MPEG-4 audio encoding. |
Quality | Apple Devices, MPEG-4, QuickTime Movie | Use this pop-up menu to select the quality of the audio output. |
Bit rate | Apple Devices, MP3 File, MPEG-4, QuickTime Movie | Use this pop-up menu to set the bit rate of the audio output. For stereo encoding, rates of 192 kbps and 224 kbps are typical and will produce good results. For Dolby Digital 5.1 encoding, a rate of 384 kbps is recommended. For Dolby Digital Plus encoding, a rate of 192 kbps is recommended. |
Use variable bit rate encoding | MP3 File | Select the checkbox to have Compressor encode the file using a dynamic bit rate that varies according to the complexity of audio. Variable bit rate encoding can reduce the size of the output file. |
Bit rate strategy | Apple Devices, MPEG-4, QuickTime Movie | Use this pop-up menu to select the method used to encode the audio:
|
Include Lt Rt downmix track | QuickTime Movie | Select this checkbox (available when “Channel layout” is set to more than two tracks) to add an additional stereo track to the transcoded file that includes a stereo-mix version of the audio with the encoded surround information included. |
Compression | Common Audio Formats | For FLAC file types, use this pop-up menu to manually set the amount of compression used to encode the audio signal. |
Joint stereo | MP3 File | Select the checkbox to have one channel carry information that’s identical on both channels, and another channel carry unique information. At bit rates of 160 kbps and below, this preset can improve the sound quality of your converted audio. |
Smart encoding adjustments | MP3 File | Select the checkbox to have Compressor analyze the source file and the preset’s encoding properties to maximize the quality of the output file. |
Filter frequencies below 10 Hz | MP3 File | Select the checkbox to have Compressor remove inaudible frequencies from the source file and output a smaller and more efficient file without perceptible loss of quality. |
Channels as | MXF | Use this pop-up menu to set the distribution of audio channels. "Mono tracks” uses a separate track for each audio channel, while “Multitrack” combines all audio channels into a single track. |
The Audio inspector also shows options for adding audio effects.
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