Saturday, January 07, 2006

Computer!



Step one if the grand media pc experiment has been undertaken. Alright, step two. Step one was gutting the original media pc to become the server. Step two was purchasing a new pc to replace it. New as in used, of course. In this case, my Compaq Deskpro was previously loved by the good folks at Universal Studios, which is somehow fitting. I got it on ebay for $77, shipped. It's a Pentium 3 1.0 gHz. It also is the exact width of most entertainment center shelves.

That leads to the next steps in my plan. My simple goal is to have two things: a machine that will digitally record "My Name is Earl" for me when I'm out, and a machine that will display such things onto my television. There are three things you need for that: a computer, a video card with outputs that are compatible with the television, and a video capture/tuner card that obtains the tv programs.

Sidebar: to get video into a pc in this manner it needs to be converted to MPEG format. That involves the hardware basically taking an uncompressed snapshot of each frame of video and then compressing it. There are two ways that can be done: the adapter card takes the snapshots and sends them to the main processor for compression through software. This allows the card to be very cheap, because it's not really doing much. Or, the card itself can have a chip that does the compression, sending only compressed data to the computer. That's better for three reasons: the theory is good, specialized bits for specialized things. Two, you are sending far less data through the already strained (even on the best computers) datapaths. Three, your processor is needed for more inportant things, like making the paperclip talk. It's like modems- even now, there are the $12 modems and there are the $50 modems. The cheap ones, that only work in Windows generally, replace some hardware with software emulation. Great if you want to build a $99 computer, bad if you want any performance at all.

Same thing with the display- video cards with hardware mpeg decoding can be sent the compressed mpeg data right from the disk, rather than using the main computer to decompress it. With video cards, this is becoming less of a cost thing and more of a feature thing. It's got it or it doesn't.

So, you can save $200 on adapter cards and build a screaming 3 gHz $1500 monster with fans-a-blazin' that uses 200W of power and needs to be in another room because it's so loud, or not. I choose the other way. We'll see how it goes.

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