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In-reply-to: Your message of "Sun, 01 Jun 2008 01:41:00 CDT."
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Date: Sun, 01 Jun 2008 08:22:10 +0100
From: Dieter <freebsd@sopwith.solgatos.com>
Subject: Re: pvrxxx recording 
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> > Is there extra overhead to compressing something straight out of the
> > tuner? Using a similarly performing algorithm, (2x on each axis, 4x
> > the power, right?) should be possible real-time with the same 45-65%
> > CPU utilization.
> 
> Not sure what you mean.  In my case, the video coming out of the card is
> compressed.  I'm certain a standard PCI bus cannot handle the bandwidth of
> raw video very well, as I've seen with my bktr cards.

Analog tuner cards without hardware compression send raw uncompressed video
over the PCI bus and it works fine.  If I've calculated correctly, 720x480
4:2:0 would be approx 15.5 MB/s.

Uncompressed HD would likely be a problem, especially if anything else
wants any PCI bandwidth.  4:4:4 would be impossible.  But then I don't know
of any cards that capture raw HD.

Doing lossy compression once is bad enough.  Compressing and uncompressing
multiple times is a recipe for ugly video.