Home » API Reference » Encoding Settings » Rate Control » Audio Constant Bitrate


:Boolean permalink

API Versions: V1, V2

Parent: outputs

Default: false

Valid Values: true or false

Compatible Job Types: All

Example: true


Enable constant bitrate (CBR) mode for audio, when possible. audio_sample_rate may be adjusted for compatibility.

audio_bitrate setting must also be specified when using this option.

Compatible with AAC and MP3 audio codecs. Not compatible when used with the VP6 video_codec.) For MP3 audio, only certain bitrates are compatible with this option: 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320.

Note: The AAC codec does not define a fixed CBR mode, so there are still small variations in bitrate over short time periods. Most software will still report these encodes as VBR.

  "input": "s3://zencodertesting/test.mov",
  "outputs": [
      "audio_constant_bitrate": true
  <outputs type="array">
      <audio_constant_bitrate type="boolean">true</audio_constant_bitrate>