Did I hear someone say GoPro Hero HD4...??

Just remember that it'll be new integrated chip, like AMD or Intel are working on (check latest Z Atoms). All in one. Probably four core. USB 3.0 (updated) controller.

But i dont understad why use A9 when you can use A15.

Because license cost real money. And A15 is more complex also.

For this thing to be real raw camera you need good heatsink (otherwise it'll be constantly slowing down), four 2GHz A15 cores and small core to oversee things. Looks similar to Tegra (Nvidia Tegra 4 T43) :-) Also, of course, USB 3.0 integrated, and SATA. Add here 64 bit DDR3 memory bus.

@endotoxic @Vitaliy_Kiselev

Besides the obvious hardware specifications, I am pleased to see the openness and flexibility of the platform. As I understand, the Dual Core ARM Cortex-A9 CPUs should be enough for basic imaging data applications including data streaming. Fabricated in Samsung's 32nm HK-MG process, "the A9 offers very low power consumption, enabling 4K resolution video cameras with small form factors and extended battery life."

Anandtech ( http://www.anandtech.com/show/6652/ambarella-announces-a9-camera-soc-successor-to-the-a7-in-gopro-hero-3-black ) has discussed the A9 and compared it with the previous generations of Ambarella's camera SoC, A7, that is used for the GoPro Hero 3 Black (the Hero 3 White and Silver have A5S SoC), built on Samsung's 45nm CMOS process. "The A9 SoC also includes two ARM Cortex A9s onboard at up to 1.0 GHz, up from the single ARM11 at 528 MHz from the previous generation. Ambarella claims under 1 watt of power consumption for encoding a 1080p60 video on the A9 and under 2 watts for 4K30 capture. The A9 also has built-in support for HDR video capture by combining two frames - thus 1080p120 becomes 1080p60 with HDR enabled. I got a chance to take a look at both HDR video capture on the A9 as well as 4K30 video encoded on a development board and decoded using the same board on a Sony 4K TV. I came away very impressed with the resulting video quality, clearly the age of 4K/UHD is upon us with the availability of inexpensive encoders like these that will make their way into small form factor cameras."

I'll tell you a truth. There are engineering internal settings editors for various ambarella chips floating around on the net. This will be how gopro set theirs up for 4k. Various cameras have combination button access to internal configuration editor. If you use, you can hack many similar cameras, more than ever done here so far. If set to max and menu settings for shutter etc and manual control configuration, a big improvement.

gopro forums have experimented.

Another truth. Latest chips can pull raw off of the right sensor at high frame rate before compression. So 4kp60±. It would be interesting if such raw could be output to new ultra high speed sd card, Usb3 or hdmi uncompressed then to recorder black magic may make cheap one again. If not, circuit traces might yield data.

If it could at least be made to output uncompressed clean live, that would be useful.

Many older chipset cameras might be made to do fullhd or better uncompressed Still, like a pocket gh2.

See here for nice example under revision for this year:

iainsinclair.com/products.php?page=3