Ambarella A9 vs A12, Which is best?

General discussion
Ambarella A12
Ambarella A9

Which is best? The A12 has some awesome cameras, the Mijia 4k, the SJ7 Star and the Thieye t5e. The Ambarella A9 is used by the GoPro 5 Black.

Looks like the A9 was specifically made for the gopro or have I got this wrong? As a lot more use the A12 than the A9.