[mythtv] Question about hardware MJPEG

Ray mythtv-dev@snowman.net
Mon, 25 Nov 2002 23:11:35 -0700

On Mon, Nov 25, 2002 at 08:58:18PM -0500, Chris Liscio wrote:
> How are you guys with the MJPEG hardware using mythTV currently?  Is it part
> of a digital cable/satellite setup, or is the hardware MJPEG card able to be
> used for offloading the compression process without using the inputs/outputs
> on the MJPEG hardware.  If you are using the inputs/outputs, is the OSD
> coming up on the output stream??

I'm using my Marvel G200 with Directv.  I'm using the hardware mjpeg for
compression and doing the decompression in software (at the moment it
doesn't seem possible to do both in hardware at once.  One glitch is that my
Dual Celeron 500 box can't quite decompress full resolution mjpegs in real time
even though it has no problems with mpeg4 or dvds at full resolution but
even at decimation 2 the picture looks pretty decent.  The OSD works just
like with it does without hardware compression.

> I had an IOMega Buz and a miroVideo DC30+ card laying around here for the
> longest time, but didn't see any use in either of them until now.  If I can
> just utilize the cards for offloading the MJPEG process, that would be very
> useful to test out.  I have some friends who are interested in the mythTV
> idea, but I keep getting laughed at when I mention it requires something in
> the P42000 range to run... ;)

AFAIK this has only been tested on the Matrox cards but it has a reasonable
chance at working with the Buz.  Last I saw the Linux DC30 drivers were
still a little flaky but maybe that's improved.  Longer term I don't think
hardware requirements are an issue even with software compression.  As of
today the slowest cpus that even make financial sense are 1.7GHz Athlons and
they're plenty fast enough for Mythtv.  I think Intel may have an even lower
power & faster P3 in the works that might make a perfect Myth cpu and
Improved support for AMD's PowerNow will help on the Athlon side.

> Any info about your setups would be great.  It would also be neat if we
> could potentially go out and find a hardware MPEG2 or MPEG4
> compression/decompression board that we could muck around with.  I *am* a
> device driver programmer by trade... ;)

I think that'd be great but I doubt it'll happen.  Consumers see mpeg4 or
divx5 compression on the box and they just assume it's done in hardware
even if it isn't so what's the advantage for the manufacturer to actually
include it in hardware.  I hope I'm wrong and the WinTV hardware mpeg2 card
takes off.


> Cheers,
> Chris
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev