Home » API Reference » Encoding Settings » AAC » Force AAC Profile

force_aac_profile

:String permalink

API Versions: V1, V2

Parent: outputs

Valid Values: aac-lc, he-aac, or he-aac-v2

Compatible Job Types: All

Example: he-aac-v2

Description:

Force the use of a particular AAC profile, rather than letting Zencoder choose the best profile for the bitrate.

The AAC audio codec has several profiles.

AAC-LC ("Low Complexity") is the most common AAC profile, and virtually every AAC decoder supports AAC-LC. AAC-LC allows mono and stereo, with sample rates from 8khz-96khz, and high bitrates (>300kbps). Use AAC-LC when encoding stereo content at 80kbps and above or mono content above 40kbps, or when you want to support devices that only play AAC-LC, like the Roku or old iPods.

HE-AAC ("High Efficiency") is a widely supported AAC profile that sounds better than AAC-LC at low bitrates by implementing Spectral Band Replication (SBR). HE-AAC supports mono and stereo content at sample rates of 16khz-48khz and bitrates ranging from 16kbps-128kbps. Most web and mobile decoders support HE-AAC, including Flash, HTML5 (wherever AAC is supported), iPhone, iPad, Android, etc. Use HE-AAC for stereo content below 80, or low bitrate mono content.

HE-AAC v2 is optimized for even more aggressive compression than HE-AAC by adding Parametric Stereo (PS) to HE-AAC. This means that HE-AAC v2 is only suitable for stereo content; mono content can only use HE-AAC. HE-AAC v2 is supported by Flash, HTML5, and some mobile devices (Windows Phone 7, Android). Use HE-AAC v2 for stereo content below 40kbps or so, but not for iOS audio. (Newer iOS devices can play HE-AAC v2 content, but ignore the PS information, resulting in mono content.)

{
  "input": "s3://zencodertesting/test.mov",
  "outputs": [
    {
      "force_aac_profile": "he-aac-v2"
    }
  ]
}
      
<api_request>
  <input>s3://zencodertesting/test.mov</input>
  <outputs type="array">
    <output>
      <force_aac_profile>he-aac-v2</force_aac_profile>
    </output>
  </outputs>
</api_request>