[mythtv-users] HDMI Capture

[Steven Adeff]

On 9/18/06, list at onnow.net <list at onnow.net> wrote:
> Quoting Gene Stapp <genestapp at gmail.com>:
> > Graeme Wilford wrote:
> >> On 12/09/06, Steve Daniels <steve.p.daniels at googlemail.com> wrote:
> >>
> >>> Just seen this in the register:
> >>> http://www.reghardware.co.uk/2006/09/12/blackmagic_hdmi_editing/
> >>> http://www.blackmagic-design.com/products/intensity/
> >>> Reckon something like that could be used in linux as a capture device for
> >>> myth maybe?
> >>>
> >>> Please feel free to ignore if this is a rubbish idea..
> >>>
> >>
> >> So presumably, it may be possible to capture off-air HD in the UK?
> >>
> >> Say, taking the component output of a SkyHD box, converting it to HDMI
> >> using something like this:
> >> http://www.gefen.com/kvm/product.jsp?prod_id=3569 and then throwing it
> >> at the intensity card... ?
> >>
> >> I'm stuck with SD on NTL and a PVR350 right now but this does sound
> >> interesting...
> >>
> >> Cheers,
> >> Wilf.
> >>
> > I emailed the blackmagic development team about the intensity card. It
> > looks like on the fly compression is doable with a dual core from what
> > they are saying. It's just a driver/codec design thing now. Uncompressed
> > HD would require us to raid 0 about four 500GB drives to have enough
> > storage and transfer speed for 4 hours of 1080i content.
> > here is their reply:
> >
> >
> > The Intensity card has generated quite a lot of interest with the
> > Linux and Open Source community, something which we did not expect.
> >
> > 1. In the Windows platform, we allow the user to capture and compress
> > on the fly to a JPEG format while on the Mac, to DV, PhotoJPEG as
> > well as DVCPRO HD. A fast processor will be necessary and also a
> > capture friendly codec. Certain codecs don't fare well with on the
> > fly compression, d.g. HDV.
> >
> > 2. Uncompressed HD video will require more than 100MB/sec of transfer
> > rate. I've attached a small clipping from our PDF manual with some
> > typical transfer rates using the Apple or Blackmagic Uncompressed
> > 4:2:2 and 4:4:4 codecs for your reference.
> >
> > 3. The compression on capture (if chosen) is in real time but this is
> > done in software, relying on the processing power of the system. We
> > don't have any hardware acceleration built in. Uncompressed capture
> > actually requires less processing power.
> >
> > A. I'm not sure of the requirements for post capture compression but
> > dual cores and quad core machines should be fine. We use dual cores
> > PCs and Macs in our labs as well. I guess post processing is simply
> > takes up less time with more powerful hardware.
> >
> > 4. You're correct. We don't have any Linux drivers. However, the
> > response from the Linux community has been good and we've notified
> > our engineers about it. Hopefully, this is something that can look into.
> >
> > Regards
> >
> > Kristian Lam
> > ---
> > Blackmagic Design
> > http://www.blackmagic-design.com
> >
> >
> >> I am a user sometimes code contribute of a popular open-source
> >> Linux based pvr system - Mythtv. The new Intensity HDMI capture
> >> card coming out looks like it may be the perfect hardware input for
> >> cable boxes/high def content coming through non-encrypted hdmi. I
> >> have some questions about the capability of the hardware that I
> >> didn't see listed on the website or spec sheet anywhere.
> >>
> >> 1. What would it take to compress the video coming in real-time to
> >> make the huge amounts of data easier to manage.
> >>
> >> 2. What kind of storage requirements/read and write speed
> >> requirements are we talking here. As you know, uncompressed HD
> >> takes up massive amounts of space. Many mythtv users run very large
> >> raid 5 arrays above 1TB with transfer rates usually between 60MB
> >> and 100MB a second (if not higher)
> >>
> >> 3. Does this device use any form of hardware compression or is
> >> everything software based.
> >>
> >> A. If it's hardware or software, what kind of processing power are
> >> we needing for compression/partial compression with multi-pass
> >> compression later say after the recording is finished. Dual-core?
> >> Quad-core? A lot of us run dual processors in the 4ghz range with
> >> large amounts of ram.
> >>
> >> 4. I know you currently do not have Linux drivers, but the Linux
> >> development community can make those easy enough if the intensity
> >> card can be adapted as a HD capture device.
> >>
> This is excellent.  I for one, would be willing to shell out for 8
> drives in a raid and the card.  Whats the next step from here?
> Linux drivers?

Or an Intel Dual Core for on the fly mpeg2 encoding. Or a "PVR"
version of the card with onboard mpeg encoding...

-- 
Steve
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