[mythtv-users] HDMI capture card with linux drivers

Brian Wood beww at beww.org
Thu Apr 15 17:47:58 UTC 2010

On Thursday 15 April 2010 11:35:05 am George Galt wrote:
> > The first thing you would need would be a LOT of storage. I think this
> > device creates uncompressed video, difficult to deal with in a Myth type
> > system. Compressing it on the fly in software would require a LOT of
> > computing grunt.
> >
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> Seems like it may have some form of hardware compression, though it's
> not clear.  The site says:
> On Windows, Blackmagic's full resolution (1920 x 1080) professional
> quality compressed HD codec can capture JPEG AVI files in real time
> using Premiere Pro. Unlike HDV and DVCPRO HD which uses reduced
> resolution 1440 x 1080 video, Blackmagic's Online JPEG maintains the
> full resolution 1920 x 1080 resolution of HD video without the huge
> file size of uncompressed HD video. Blackmagic's Online JPEG is so
> efficient that full motion 1080i HD video can be recorded at only 12
> MB per second vs. a massive 119 MB per second for uncompressed HD
> video.
> Blackmagic's compressed files are so compact, that 1080 HD video can
> be captured to a single internal hard disk or easily transported on a
> portable Firewire drive! Online JPEG is compatible with Premiere Pro
> and After Effects® and can even be used by editors without Blackmagic
> capture cards making it one of the most versatile compressed codecs
> available.
> Words that seem problematic are "Blackmagic's full resolution (1920 x
> 1080) professional quality compressed HD codec ", which I assume is
> proprietary and closed -- though I will note that one of their devices
> lists Linux as a compatible OS.
> This doesn't mean that there isn't a host of other issues with this
> device, but at least it seems like it is doing some form of hardware
> compression (though 12MB per second (sic) doesn't seem all that
> great).

It does seem like they are doing some sort of compression, I guess I missed 

Anything that can capture HD from an HDMI port would probably be locked down 
pretty tight, as HDCP is the only thing "protecting" HD now.

Of course it might mute some of the cries to close the "analog hole" 
(component outputs) if there was a alternative available to the "pirates".

Hypothetically, and theoretically, some of the HDMI "splitter" devices will 
output clean video if just one of the ports has HDCP, or so I have heard.

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