MythTV summer project...

N

nephilim

Limp Gawd
Joined
Jun 10, 2004
Messages
178
Just checking with those more in the know than I:
Planning on a whole slew of home improvements this summer, already wired the house with Gigabit/108Mbps wireless and a Linux firewall/router. Stage 2 is a distributed MythTV network. I'm stuck between 2 plans here:
1. VIA MII boxen /w Hauppage 250's for capture. MythTV is (obviously) network-aware so any box on the network can get content ffrom any of the others. The MII has hardware acceleration for MPEG-II, so I don't think the CPU would be stressed by simultaneous record/playback.
2. Single server in the basement (AXP 2400+, 512MB, 8 WD 120-gig in RAID-5) with multiple tuner cards using XBoxes as frontends throughout the house. ($100 for a refurb/used, built-in TV-out and DVD remotes are cheap.)
I'm leaning toward #2 right now, as you can use them as XBox, MAME, SNES, MP3, PSX, etc. when they're not watching recordings. Obviously the other setup couldn't record while playing games because of the hardware limitations. (Also, it's cheaper. Still, I like the idea of distributed recording in case something bombs.) I was just looking for feedback on the potential setup or if anyone could think of an improvement.
 
The second one sounds best. I know a few people that tried using the little VIA boards with a 250 and XP and the CPU usage is something like 90ish% for playback your using linux so your mileage may vary. Personally I would setup some sort of distrobution "network" by building "set top" boxes use those VIA boards for every TV with a central server sending out video to them. Make sure your cable has enough bandwidth for multi cards too.
 
Sounds quite intriguing. I'd like to know more about the use of the Xbox as a frontend. I'm installing MythTV right now on a spare PC and like the idea of an Xbox front to the system.

Can you go into more details?
 
I had a very simple Myth setup last summer. A single computer was both frontend and backend (which is a HORRIBLE idea.) I did have the benefit of a Hauppage PVR-250 which reduced CPU usage. Back then, Myth was arund version 0.11 and it crashed ALL the time. I haven't used it since. I record my shows by hand or with a perl script. (sidenote: ivtv takes a little tweaking sometimes ... I also build from source)

Long story short, I now use the same box to record shows by hand/perl. I then have them Samba shared so that the XBOX (running XBOX Media Center) can play them over a 100mbps connection. The output quality from the XBOX beats the pants of three other video cards w/ tv-out I'd previously tried. The XBOX solution is pretty good, IMHO.
 
i'd definitely advise against the via boxen simply because it would probably cost about the same to go with more powerful setups. Option 2 sounds like a very neat idea, but how many tuners do you plan to use in the server? Also, though i'll admit i'm not so learned when it comes to sharing video over a network, if you have multiple frontends playing video's from the backend server it will most likely be fairly taxing on your network, and you want to be sure you have more than enough bandwidth so you may want to look into picking up a switch with a gigabit port (i know dell has one that fluctuates in price between 80 and 127 depending on the deals available). Granted i could be entirely wrong and 100mbps might be enough, but i think that if you're doing something such as this you need to make sure that in every scenario it's gonna run fine. Sounds very cool though, keep us posted!
 
CrimandEvil:
See, for that kind of networx the XBox makes more sense just from a cost/performance basis. They have hardware decoding, TV-out, and I don't have to worry about compatibility with the remote/video card/network/etc. The bare motherboard for an MII 10000 costs about $200, whereas an XBox used runs $100-120 for the whole setup.

Antheus:
The backend would be gigabit, yes. I've got the backbone laid in already, with an 8-port gigabit switch for intensive stuff and 108Mbps wireless for Internet/gaming.

carl67lp:
As to the XBox... If you can get ahold of an older one there are exploits one can use to boot Linux while retaining functionality as an XBox. (No modchip needed, no pirate BIOS, totally legal. Check xbox-linux.org) Only drawback is that you can't use the Live (online) stuff, which is fine as every account has a monthly fee. Read up first, and DON'T hook up the network until you have the mod working. There's an automatic update which can render the technique ineffective. After installing the mod it won't accept that update anymore.

ZeroX:
Looking around on MythTV's forums (I'm leaning towards knoppMyth - a knoppix minimal install that just runs MythTV) it seems that as long as the hardware is compatible there aren't many stability problems anymore. AFAIK MythTV has a modded version of ivtv built in already, and I'd say more than 50% of Myth users have 250 cards so support shouldn't be a problem if something does go wrong. (The 350 works as well, but the hardware decoding is buggy.)
 
Okay
#1 Don't use a via based chipset for a myth box. There are many stories of peoples PC's locking up when attempting to record something. It has something to do with PVRx50's and the linux drivers not agreeing with via based board. Get an Nforce2 board.

#2 I actually got the MythTV backend running and the frontend running on the xbox. First off keep in mind the Xbox only has 64MB of ram, and it does NOT have a built on MPEG2 decoder. MPEG2 streams would be decoded by the CPU which is only a 733Mhz processor. Also, I cannot remember for sure but check to make sure that LIRC (the linux Infra-Red software) supports the xbox remote, because the IR dongle that you buy for xbox has firmware built into it that may restrict other software from accessing it. Again Im not %100 sure on this so double check.

#3 Finally Mythtv does run on xbox, and is a fairly nice setup but it also quite slow and there are noticeable delays when navigating the menus. A 100Mbit backbone should be fine for all your video needs, but if you have the extra money to blow invest in Gigabit (which it sound like you do :) )
 
Err, XBox kind of HAS to have an MPEG2 decoder, else how does the DVD player work? Either way, if it can handle a DVD then it should be fine for my TV needs. (480x480, 16-bit 44.1 stereo audio. I'd settle for 352x480.)
The XBox remote works on an RCA universal remote code, and is preconfigured on the MythTV-XBox distro. (Nice having to code for only one possibility. Dunno about 3rd-party remotes, though.)
As for navigation speed, well, I've got an old series-1 Tivo upgraded to a 300 hour. Loading the menu takes from 6-12 seconds, adding a new season pass takes upwards of a minute. Myth CAN'T be that bad, especially as most of the processing aside from decoding/games would happen on the backend. (I believe the old Tivo used a 60MHz PPC processor. New ones use MIPS.)
Yeah, I heard about the VIA problem. Even in an nForce2 you have to disable APIC support both in BIOS and the kernel, so that's not perfect either. Hearing that I'm kind of leaning toward a P4 2.4 and a mobo with built-in gigabit, which should be fine for recording/indexing only. (I'm usually a staunch AMD advocate, but practicality wins out.)
 
Actually the Nforce2 APIC problem is fixed in the 2.6 kernel i believe so that is not an issue anymore. You can use whatever you want (obviously :) ) just be prepared for a possible up hill fight when using VIA. The delay you described on the tivo is no where near that of the xbox. The delay of the xbox is more like a 2 - 3 second delay. Furthermore most processing does not take place on the backend. In fact you could setup an old althon 1gig w/256meg ram as the backend and that would be overkill. The only processing the backend is doing is encoding the MPEG2 stream, running lircd, and mysql. The front-end decoding stream, rendering menus, etc.
 
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