Hi,
the Ambarella A9 SoC can encode H.264 codec BP/MP/HP Level 5.1, you can find this in the Ambarelle datasheet.
BP = BaselineProfile, MP=MainProfile, HP=HighProfile
At Level 5.1 HP the bitrate is 300Mbps, at BP/MP it´s 240Mbps, the SoC is capable to encode Level 5.1 HP.
You need a fast SD...