Yep, if you want to set up a media computer, ie something to record and play back tv, play downloaded movies & songs, play dvd's, tell you the weather etc the best solution still seems to be an x86 family machine, although it might also be worth contemplating a mac mini.
The main "power" requirements come from processing video. When watching live TV a mythtv box compresses video to the hard drive and decompresses it at the same time. There is a delay of about 2-3 seconds, but it means that you can pause, rewind, skip thru ads etc. Therefore you either need a grunty CPU or some non cpu hardware that can compress/decompress to a reasonable codec. VIA's M series motherboards are quiet and small and capable and most importantly they decompress MPEG-2 in hardware, so theres the decompression off loaded. They also do TV out, six channel analogue and six channel digital (SPDIF) sound out and IEEE1394 (firewire) in for your video camera. Most TV tuners/video capturers dump raw uncompressed video into the PCI or USB bus, so the CPU has to compress it to the hard drive. However hauppauge make a series of tuner/capture cards that do hardware mpeg-2 compression. They also make a card that does hardware decompression too. Both the via hardware decompression and the hauppauge compression cards have working but problematic linux drivers [1] - problematic in that they have not made their way into official kernel or xorg sources and are not easy to get working straight out of the box. . They are probaly easiest to get going on gentoo with its flexible ebuild system (is my bias showing now?). [2] Of course mpeg-2 does not compress as much as mpeg-4, and unfortunately I have yet to see a consumer device that does hardware compression and decompression of mpeg-4, although the new VIA EPIA-SP motherboards promise "the Chromotion CE Video Display Engine of the S3 Graphics UniChrome Pro IGP graphics core features hardware-based MPEG-2 decoding and MPEG-4 acceleration for smooth playback of the most popular video formats,together with Adaptive De-Interlacing and Video De-Blocking advanced video rendering functions for unequalled image crispness." For a pure player of downloaded or dvd based video the requirements are lower. My VIA box is 900MHz with 256 M RAM and plays DVD's and divx files just fine without resorting to hardware decompression. (Anyone want to know what happens at the end of Lost BTW? Or see the new series of Dr Who?) The cpu load goes up to 80 % odd at times, but it doesn't do anything else so who cares? [1] Unichrome for via and ivtv for hauppauge [2] Gentoo is also pretty easy to strip back too, but if you are going for a hard disk based system then the saving is negligible. For example I have not stripped any of my media player system and the hard drive has 55G on it, of which 52G is "media" and 0.5G is source files that I could delete. I could make more room by deleting the build system (rendering my "build" as static) or documentation/man pages etc. But I see little point. On Wed, 22 Jun 2005 09:06:33 +1200 Craig FALCONER wrote: > "media" to me implies sound, still pics and video, and TV tuner. > > Very few of the low-power CPUs will have the gumption to compress or even > play video. You'd be better off looking at a board with a VIA CPU, or even > a full-blown modern CPU. > > As for software, mythtv and friends can be useful. > > > -- Nick Rout
