Netflix has employed the xHE-AAC audio codec for content streamed on its Android app. The streamer has licensed the high-quality audio software from Fraunhofer IIS.
One of the key features of xHE-AAC for Netflix is the mandatory MPEG-D loudness and dynamic range control metadata, which allows service providers to embed content- and endpoint-specific metadata in the audio bit stream for transmission. This metadata can then be used on the playback side to achieve a consistent loudness level and optimal dynamic range for any playback device and environment.
Fraunhofer gives the example of a film being watched in a living room environment where it will sound the way it’s supposed to. Watching the same film on a mobile while in a noisy environment might require loudness management so that the viewer can hear everything clearly. The MPEG-D metadata is a single stream that meets the needs of both of uses.
xHE-AAC also offers Netflix improved coding efficiency at low bit rates, an ability to scale up to perceptually-lossless quality at high bit rates, and built-in bit rate switching. According to Fraunhofer, this enables Netflix to always stream with an audio bit rate that matches the currently available internet speed, achieving very high quality for high-bandwidth connections, and minimising rebuffers during network congestion.
“Our xHE-AAC audio codec has been designed from the ground up to improve the consumer experience for entertainment content especially in environments with limited Internet bandwidth,” said Bernhard Grill, director of Fraunhofer IIS. “With Netflix as the leader in video streaming worldwide, we couldn’t have found a better launch partner for xHE-AAC in this market segment.”