[MPlayer-users] Dream video machine or nightmare?

[Yan Seiner]

Simen Thoresen wrote:
> 
> While I too have not /done/ this, I'm wondering what you have against 
> compression. An uncompressed video-stream is huge and will tax IO, while 
> a hardware-compressed video-stream is comparably puny. I'm using 
> Hauppage PVR 250-cards, which deliver a low-bandwidth MPEG2-stream to 
> the system. I would be surprised if even modest harware would have major 
> issues with 4x 15mbps (7MB/s hd-speed) video streams. The quality of the 
> compression is (imho)
> good enough for post-processing work, and most cheap BT8x8-clones 
> produce more noisy output than what I'm seeing from the Hauppage card.
> 
> I'd also go for a sriped working-disk like the other poster wrote, and 
> then copy to a mirror for postprocessing. Depending on the size of your 
> data, you could even have one stripe-partition and one mirrored 
> partition on the same drive, provided you don't simultaniously copy one 
> set while grabbing another.
> 
> Still - this sounds fun. Please keep us informed :-)

Thanks for all the input.  Just to let you know what we're doing, and 
what drives my decisions, here's a bit more detail:

I will put 4 small cameras inside a fairly large structure, aimed at 4 
stress points where we assume failure will occur.  We will then stress 
the structure to failure.

I am assuming that the cameras will not survive, so I am looking at $100 
or so 'disposable' cameras.  The cameras provide about 400 lines of 
resolution, so I am assuming that 640x480 will be sufficient to capture 
all the detail that the cameras are capable of capturing.

Because of the nature of the test, this is a one-time (possibly 2 time) 
deal.  The test is expensive - we are destroying a piece of production 
machinery/structure - so I don't want any chance of losing data.

We may have use for 1 computer, but we really don't want to buy 4 
computers.  So I want something I can use later as a general-purpose 
worksation or a small workgroup server.  (Hey, if I get a SMP 
workstation out of this, that's cool.)

My initial objection to compression is the CPU required, but it looks as 
though there is probably no way to get an affordable hard disk array 
that can handle 4 uncompressed streams.  That works out to 40 - 60 
MB/sec sustained write net of overhead, which is beyond the 32 bit PCI 
bus, and may tax even 64 bit PCI depending on the FS overhead, and we're 
talking an expensive SCSI controller with hardware RAID.... So, we'll 
probably look at some of of the compression cards.

So.... Recommendations for hardware compression video cards?  Hauppage 
PVR 250?

Thanks,

--Yan


-- 
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Yan Seiner      (_)\(_)       ,>/'_     o__
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Who says engineers have to be pencil necked geeks?  (_)\(_)
yan at seiner.com - Eugene, OR - 541.513.4838 - http://www.seiner.com