Android version Netflix adjusts audio for bandwidth and background noise

Netflix has started offering audio in a new codec that automatically adapts to bandwidth and background noise in the user’s environment. With a lot of background noise, the dynamic range decreases, while dialogue is louder.

The new codec should therefore ensure that users have to adjust the volume less, Netflix says. Tests by the streaming service also show that people with the new codec are less likely to switch to using earphones.

The codec is called xHE-AAC, Extended HE-AAC with MPEG-D DRC metadata. For the new codec, users will need Android 9 or newer; as a result, a large proportion of Android users are provided with a compatible device.

The bitrate of the audio automatically adapts to the bandwidth. In addition, the audio can adapt to the background noise of users. If there is more background noise, the dynamic range of the audio will be smaller and therefore the difference between, for example, a whisper and an explosion is smaller. The most important thing is dialogue at a normal level; it must always be audible, the streaming service reasons.

During tests with the new codec, fewer people reached for the volume knob and earphones than with the previously used codec. This indicates that the interventions make sense and that the codec is doing its job, according to the streaming service.

From left to right: distribution of audio levels without adjustment, with normalization, with adjustment to make dialogue more audible and with adjustment and visualization of background noise