[st-ericsson] v4l2 vs omx for camera

Marek Szyprowski m.szyprowski at samsung.com
Tue Mar 1 02:51:17 PST 2011


On Tuesday, March 01, 2011 11:26 AM Edward Hervey wrote:

> On Mon, 2011-02-28 at 09:50 +0100, Marek Szyprowski wrote:
> > Hello,
> [...]
> >
> > I'm not sure that highmem is the right solution. First, this will force
> > systems with rather small amount of memory (like 256M) to use highmem just
> > to support DMA allocable memory. It also doesn't solve the issue with
> > specific memory requirement for our DMA hardware (multimedia codec needs
> > video memory buffers from 2 physical banks).
>   Could you explain why a codec would require memory buffers from 2
> physical banks ?

Well, this is rather a question to hardware engineer who designed it. 

I suspect that the buffers has been split into 2 regions and placed in 2 different
memory banks to achieve the performance required to decode/encode full hd h264
movie. Video codec has 2 AXI master interfaces and I expect it is able to perform
2 transaction to the memory at once.

Best regards
Marek Szyprowski
Samsung Poland R&D Center

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