RE: HD Capture Card (HDMI and Component) output raw pixels

Charlie X. Liu
2013-06-19T01:34:58Z

Right -- not practical, since you need 1920*1080*3*50 = 311.04MB/s bandwidth
to transfer from PCIe and save the raw date onto a SSD, at which the PCIe
1.x link x1 (max 250MB/s) can not really meet such requirement.

Well, PCIe 2.x link x1 can meet since its max is 500MB/s. Or, using YUYV, a
more common format, would be fine, since it requires 207.36MB/s and reduces
the storage requirement from 1.119744GB (1920*1080*3*50*60*60, with RGB
format) to 0.746496GB (1920*1080*2*50*60*60, with YUYV format).

Best,

Charlie X. Liu

-----Original Message-----
From: linux-media-owner@vger.kernel.org
[mailto:linux-media-owner@vger.kernel.org] On Behalf Of Daniel Glöckner
Sent: Tuesday, June 18, 2013 4:07 PM
To: Steve Cookson
Cc: 'James Board'; linux-media@vger.kernel.org
Subject: Re: HD Capture Card (HDMI and Component) output raw pixels

On Tue, Jun 18, 2013 at 05:55:15PM -0300, Steve Cookson wrote:
> > I don't want to configure a RAID either, but if I purchase one SSD
> > with
> 400 MB/sec write speeds, that might be good.
>
> Hmm... nice idea. Did you have any particular model in mind? If you
> had a link, I might be interested. I wouldn't know about sizing. I
> don't know how much space HD raw video takes up per hour, say.

That's easy. My current video mode is 24 bit 1920x1080 at 50 fps.
So there are 3*1920*1080*50 bytes per second or about 1.1TB per hour.
But you won't be able to capture all frames with that card. The single lane
PCIe 1.x bus will max out at 200~250MB/s.

Daniel
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