It turned out that CoreAudioToolbox 7.9.8.x or greater (upto 7.10.9.0, the latest version at the moment) can produce gliches on the encoded result. The issue is only found on AAC CBR mode.

13.7%, with a speedup of more than 2300x for HD4K over VTM-19.2. Comparing the runtime with HM gives a speedup of around 370x. As a good tradeoff between encoder runtime and BD-rate performance, we ...