Exactly the same JPEG hardware block for encode and decode is present on all variants of the Pi. Access is via MMAL (or OpenMax IL if you really must). Example app at https://github.com/6by9/userland/tree/h ... _mmal_jpeg
libjpeg with NEON enabled is likely to be pretty close to the same performance, mainly as there isn't the same setup overhead.
Software Engineer at Raspberry Pi Trading. Views expressed are still personal views.
I'm not interested in doing contracts for bespoke functionality - please don't ask.