[H-GEN] now cable capture

[Russell Stuart]

On Wed, 2010-10-06 at 11:27 +0100, Benjamin Fowler wrote:
> Somebody would have to design and build a black box to do the job. 

As things stand, I think that is spot on.

There were two problems to recording a video stream coming in over HDMI.
One was HDCP, and the other was the shear amount of data you have to
handle.

Since HDCP is gone, we are left with the minor problem of having to
process a 10 G bit/sec uncompressed video stream.  You can't push this
over a PCI-E bus, even a 16 lane one, and even if you could a modern CPU
would choke.  So it has to land onto a board that has the shear grunt to
handle that data rate, compress it and then pass it onto something that
can write the stream to a SATA bus.  Something with say 400 CPU's with a
memory bandwith of 100 M bytes/sec would do nicely.  I wonder were I
could find that?

On a NVIDIA GTX 480 (or similar) graphics card.  And it comes with a
free "C like language" compiler, so any tom, dick or harry who can read
a manual to program the GPU to do what is needed.

The one remaining problem is while every high end graphics card sports a
HDMI socket, currently they are _all_ write only, meaning they can
output a video stream but not read an incoming one.  You can speculate
why that is so.  I speculate that one reason is up till now there wasn't
any point in allowing the GPU to read in the incoming stream because
there was this thing called HDCP, which meant any incoming stream was
likely encrypted using unknown keys.