Is LC3 superior to existing codecs like Opus?
LC3 at 32 kbps (LC3 32) provides significantly better audio quality than Opus-CELT at 32 kbps and complexity level 0 (OPUS_v114_c0 and COPUS_v114_c0).
https://www.etsi.org/deliver/etsi_tr/103500_103599/103590/01...
Getting down to 700 and even 450 b/s is neat and all, but there seems (to me) to be a gap between 4000 and 10000 b/s in the patent-free space.
It doesn't seem to be a particularly lightweight codec compared to Opus, or particularly performant.
The path is almost always: input audio stream -> decode into raw PCM/PDM/TDM/whatever -> convert to whatever sample rate you're using internally -> move it to your output via some sort of audio bus -> output converts to whatever format IT needs (for bluetooth, this would be into packets to send over bluetooth... for a speaker driver, this would be into signals that drive an actual speaker)
Even if you could send Opus directly, I guarantee there's a reason that they went through the effort of developing an entirely new codec. If Opus met all their needs right off the shelf, then you bet they would spend the effort to use what already exists.
There probably is some sort of latency compensation that you could perform to alleviate this for video content (e.g., most receivers have a delay option to compensate for TV latency), but this falls apart for any instantaneous audio (e.g. button presses, video games, or other dynamic content). You want everything to run as quickly as possible.
The most obvious choice here was to allow MP3 as a codec choice, but the patents are all expired on MP3 so that's not a revenue source. Doing that would have avoided recoding for most music.
Every Bluetooth chip I've seen has enough CPU to decode any of these codecs. The only question would be power consumption during decoding.
I have a distinct suspicion that in reality the only relevant feature LC3 has which Opus lacks is that it ensures a nice ongoing stream of licensing money for the Fraunhofer Institute and Ericsson, who designed it and worked to get it into the standard.