hdmi capture card support

[nebulink]

Does sage support hdmi capture cards?
I found this one on end gadget.

http://www.engadgethd.com/2006/09/13...-card-for-249/

[heffe2001]

If that worked in Sage, I'd probably pick one up, and use it with my HD cable box via a DVI to HDMI adapter, much more reliable than the Firewire method I was using...

Originally Posted by nebulink

Does sage support hdmi capture cards?
I found this one on end gadget.

http://www.engadgethd.com/2006/09/13...-card-for-249/

[nebulink]

here's another link to the manufacturer's web site
http://www.blackmagic-design.com/products/intensity/

[stanger89]

Captures from that card are on the order of 50-600GB/hr. Not practical for a PVR.

[nebulink]

here's another card with a hardware encoder onboard.
http://www.coremicro.com/catalog/gra...sus-p-357.html
Looks promising.

[GKusnick]

Again, that card is meant for video professionals, not consumer-level DVR use. Even if you can swallow the $1000 price tag, note the emphasis on "pristine", "high-quality" video capture; that's marketing code for high bitrates and giant file sizes.

From the reviewer's guide:

In other words, compressing HD data in this way can yield a saving of 20:1 without any significant loss in quality. That’s a big saving considering that just one second of uncompressed HD at 1920x1080 is around 140MB!

So in other words at 20:1 compression it can encode HD at 7 MB/s = 25 GB/hour. A 1 TB disk could hold just 40 hours of video at that rate. File size aside, it would take essentially all your disk bandwidth to capture just one HD stream. So forget simultaneous recording of multiple shows.

As Stanger says, not practical for DVR use.

This is not the first time this sort of capture device has been proposed. I suggest searching the forum for Blackmagic to see what's been said about them already.

[m1abrams]

Originally Posted by nebulink

here's another card with a hardware encoder onboard.
http://www.coremicro.com/catalog/gra...sus-p-357.html
Looks promising.

Notice that it does NOT support HDCP which will most likely prevent it from being used for HDMI capture of cable box video. Now it does support Component inputs which do not have HDCP protection so maybe that will work.

[stanger89]

Originally Posted by GKusnick

So in other words at 20:1 compression it can encode HD at 7 MB/s = 25 GB/hour. A 1 TB disk could hold just 40 hours of video at that rate. File size aside, it would take essentially all your disk bandwidth to capture just one HD stream. So forget simultaneous recording of multiple shows.

I was about to comment that in the Canopus HQ whitepaper, their example images are from a 180Mbps recording. And I think you might be a bit off on your math 140Mbps /8 = 17.5MB/sec or 63GB/hr

As Stanger says, not practical for DVR use.

The other problem is it's a proprietary codec, it's not MPEG-2, AVC, or VC-1, it's Canopus HQ.

This is not the first time this sort of capture device has been proposed. I suggest searching the forum for Blackmagic to see what's been said about them already.

It is the first solution I've heard of south of $20k that's got a hardware encoder on it. It's just not a useful (for PVR) hardware encoder.

[GKusnick]

Originally Posted by stanger89

And I think you might be a bit off on your math 140Mbps /8 = 17.5MB/sec or 63GB/hr

I was just figuring from their figure of 140 MB/s (which I took to mean megabytes, not megabits). I don't claim to be an expert at this stuff but 1920 * 1080 * 18 bits/pixel * 30 frames/sec works out to 1120 Mbps or 140 MB/s, for whatever that's worth.

[stanger89]

Originally Posted by GKusnick

I was just figuring from their figure of 140 MB/s (which I took to mean megabytes, not megabits).

Then you're math's farther off

I don't claim to be an expert at this stuff but 1920 * 1080 * 18 bits/pixel * 30 frames/sec works out to 1120 Mbps or 140 MB/s, for whatever that's worth.

Yup, that's about right, somewhere around 1-1.5Gbps uncompressed depending on chroma sampling.

[GKusnick]

Originally Posted by stanger89

Then you're math's farther off

How do you figure? 140 MB/s compressed 20:1 yields 7 MB/s = 25 GB/hour, right?

I don't doubt that the card can do lower compression ratios, yielding even higher bitrates (such as the 180 Mbps figure you quoted). But the implication seemed to be that 20:1 was the highest ratio it can do, which (by my math) still yields unfeasibly high bitrates for DVR purposes.

[stanger89]

Originally Posted by GKusnick

How do you figure? 140 MB/s compressed 20:1 yields 7 MB/s = 25 GB/hour, right?

Oh! I was reading that different. I see what you're doing now. I was confused because I thought you saw the 140 number from a review as the after compression bitrate (and the 20:1 was just a note).

I was trying to figure out how 140Mbps /8 -> 7MB/sec (that math would be 17.5MB/sec).

I don't doubt that the card can do lower compression ratios, yielding even higher bitrates (such as the 180 Mbps figure you quoted). But the implication seemed to be that 20:1 was the highest ratio it can do, which (by my math) still yields unfeasibly high bitrates for DVR purposes.

The 180Mbps (22.5MB/sec) is from a Canopus HQ whitepaper, which would be 81GB/hr. I agree, impractically high.