Optimizing the Aural Experience on Android Devices with xHE-AAC
Article Summary
Phill Williams and Vijay Gondi from Netflix reveal how a codec upgrade is solving one of mobile streaming's most annoying problems: constantly adjusting your volume.
Netflix deployed xHE-AAC audio codec to Android 9+ devices, bringing sophisticated loudness management and dynamic range control to mobile streaming. The team A/B tested against their existing HE-AAC codec to measure real-world impact on member behavior.
Key Takeaways
- Members switched away from built-in speakers 16% less for high dynamic range content
- Volume change interactions noticeably decreased, especially for high dynamic range titles
- Fewer members maxed out volume, suggesting improved satisfaction with output levels
- MPEG-D DRC boosts soft details in noisy environments without affecting dialogue
- Adaptive bitrate audio now scales from studio quality to congestion-proof streaming
xHE-AAC's intelligent loudness management and dynamic range control reduced volume adjustments and audio sink switching by up to 16%, proving that codec-level intelligence directly improves user experience.
About This Article
Netflix members had to constantly adjust volume when switching between titles. Action films came through at -27 dBFS while live concerts sat near the top of the mix, creating inconsistent dialogue levels across different types of content.
Netflix added MPEG-D DRC metadata in xHE-AAC to bring all dialogue to the same loudness level. The Android decoder uses KEY_AAC_DRC_TARGET_REFERENCE_LEVEL to handle this normalization, which removed the need for gain adjustments during encoding.
Members stopped turning up the volume as much since content played at a louder default level, about 11dB higher than before. Fewer people maxed out their volume settings, which suggests they were happier with how the audio sounded across different content types.