Meta rolls out audio codec MLow to WhatsApp

Meta is rolling out its new audio codec Meta Low Bitrate, or MLow, to WhatsApp. It is already available in Instagram and Messenger. The codec should make it easier to make audio calls with poor internet connections.

Meta previously used the 2012 open source codec Opus for audio calls. However, the sound quality of MLow is better at a lower bitrate, Meta claims. The company has shared several audio files that show the difference between Opus and MLow.

The difference between MLow and Opus at different bitrates. Source: Meta

With MLow, PCM audio is fed into an encoder, which then splits the signal into two frequency bands: a high and a low. Then each band is coded separately. At the receiver, the tapes are again passed through an encoder to decompress them and generate an encrypted payload.

Source: Meta

Meta has not based the codec on artificial intelligence, because that requires more energy. In addition, older devices may have more difficulty dealing with AI-based codecs. The company points out that 'tens of millions of phones' that make daily calls via WhatsApp are ten years or older.