Opus 1.1 includes:

• new analysis code and tuning that significantly improves encoding quality, especially for variable-bitrate (VBR),
• automatic detection of speech or music to decide which encoding mode to use,
• surround with good quality at 128 kbps for 5.1 and usable down to 48 kbps, and
• speed improvements on all architectures, especially ARM, where decoding uses around 40% less CPU and encoding uses around 30% less CPU.

These improvements are explained in more details in Monty’s demo (updated from the 1.1 beta demo).

• Source code: opus-1.1.tar.gz

via Opus Codec.

From the Xiph.org developers

Opus is a codec designed for interactive usages, such as VoIP, telepresence, and remote jamming, that require very low latency. In this test Opus is running with 22.5ms of total latency but the codec can go as low as 5ms. Making a codec for low latency requires serious tradeoffs which reduce efficiency, so it might seem a bit strange to test it against a collection of state-of-the-art codecs which are completely unsuitable for these low-latency applications.