AAC (Advanced Audio Coding) is the baseline audio codec of OTT, supported on virtually every device and paired with H.264 and beyond. It delivers good quality at modest bitrates for stereo and is the safe default audio rendition in any ladder.
For richer experiences, platforms layer additional audio: multichannel and immersive formats such as Dolby Digital Plus (E-AC-3), Dolby Atmos, or AC-4 for capable living-room devices. Audio also carries the accessibility and localization burden - multiple language tracks and audio description - so audio handling in the ladder is more than an afterthought.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
AAC is the safe default audio codec for OTT because nearly every device plays it, yet loudness and surround tracks still cause most audio complaints. Our seven-volume handbook covers the whole video stack; for AAC start with Volume 4 on codecs, channel layouts, and loudness in LUFS, then Volume 2 on HLS and DASH packaging and Volume 3 on players. Written by Nikolay Sapunov, CEO at Fora Soft.
Is your AAC audio setup causing loudness jumps or broken surround on some devices?
We will audit your audio renditions and packaging and send fixes for loudness, channels, and device support. 250+ video products shipped since 2005.
