MythTV questions

[WanderingOak]

I have an old AMD 550 box with 1GB of RAM that I would like to make into a MythTV Backend. I know it's a low end machine by today's standards, but it is what I have on hand. If I were to use a newer video capture card such as the Hauppauge PVR-150 which handles all of the video processing onboard, would this system have enough power to record and watch video simultaneously?

My second question is regarding MythTV frontends. I've heard tell that I can use a game console such as an XBox, but I haven't been able to find any documentation of that in the MythTV wiki. Has anybody here done that? Could I use an Apple TV as a frontend for myth TV? Would something like a Roku Digital Video Player (http://www.roku.com/roku-products) have enough brains to act as a frontend?

[trilarian]

Welcome to JL!

I can answer some of your questions, and speculate on the rest. I have a MythTV Box running right now on roughly the same or worse hardware that also does more functions, so I think you'll be OK with recording and watching at the same time. Running a script, like to remove commercials, on the other hand may or may not give you hiccups depending on your hard drive I/O.

Hardware wise, I'm using:

AMD Sempron 3400+ (Single Core)
1GB RAM
2x 1TB WD GP in Software RAID-0
Hauppauge PVR-150

CPU wise, the 550 beats me assuming the google search returned the same processor - Dual Core 3.1 GHz. That extra Core will come in handy, and 3GHz is more than enough to do what you are looking for. I also have 1GB RAM with no issues, so you are good there. I can't recommend the PVR-150 card enough!! It is cheap, reliable, well supported, and hasn't giving me a problem since I installed it. Check out this page (http://ivtvdriver.org/index.php/Main_Page) for support information.

So that leaves the hard drive. 30 minutes of standard definition video runs roughly 1.x GB of data uncompressed. It is very easy to get carried away with setting recording schedules and not having the time to watch, so accumulate a lot of video data. So I'd suggest go as large as your budget allows. I personally went with the GP drives from Western Digital as they have a variable RPM speed that cuts power and noise significantly. To help keep them spinning low, I did the RAID-0 stripe in software. I backup to DVD-DL what I feel is important and don't worry about repeating shows like the Daily Show.

Lastly, I don't know if the Roku will work for you, but what I'd look to see if it does is be a client to a UPnP Video Server. If so, MythTV has an option to run a UPnP server that streams nicely. I have it streaming to my PS3 over wi-fi. I also setup the web interface using Apache so I can set programming schedules from my phone or the PS3. I rarely access the server directly, so it doesn't have a monitor, keyboard, etc.

Let me know how it turns out for you~

-Tril

[Modorf]

the amd 550 will work fine.
I would suggest a little bit more ram, 2gigs works for me.
I found that transcoding videos (compressing them) takes a bit of ram.
you'll probably be more interested in a digital tuner with ATSC/QAM support.
Also you'll want to look at your graphics card for accelerated playback.

[cybernard]

First 1 hour of 1080i is 8.5gb not what above person said. If you actually remove the commercials then it is 6.5gb. Unless you transcode everything to a lower quality.

I have to agree hard drive performance will be critical. If you have a modern HD capture card it dumps the signal, basically immediately, to your hard drive. This doesn't require much CPU. In fact, you could probably record 4 shows at the same time w/4 tuners.

Hard drive and CPU depend on if your watch it locally or remotely.
I define remotely as using a samba share, under this situation the viewing PC does all the work and myth/samba have a tiny work load.

I define locally as watching on the mythdvr directly. Then the CPU/GPU has to decode the stream which could flood the CPU which would affect any recording programs. For local watching a graphics card that accelerate via hardware decoding is a great choice.

If you use UPNP and myth has to transcode it then it is the same as local.


Note: This test requires 4GB of free hdd to get an accurate picture.
run bonnie++ -d <location of storage> -u 0
Check the block speed and CPU usage. Unless you have a RAID and your read speeds are crazy high(500mb/s+) then at a block speed of 77951(or about 70mb/s) utilization should be less than 10% read. Writing at 60mb/s should not exceed 20% for best results.

Finally, your software raid 0 has a hidden gotcha. If any disk fails all data is lost. If you record shows and delete them weekly with little or no retention then this is much of an issue. The most you would lose is a weeks worth. However, if you have favorite shows you want to keep permanently then this will eventually come back to haunt you.

First, I recommend hardware RAID 6 (RAID 5 can also work) as a good solution. Yes, most of these cards are expensive $500. However, for the serious mythdvr person who rips all there dvd/cd and records and keeps tons of stuff this is the best option. Twice I have lost everything with software solutions. Since I have gotten RAID 6 I have lost nothing. RAID 5 supports the failure of 1 drive and RAID6 supports the failure of 2 driver. Software RAID 5 and 6 are CPU expensive, but hardware version is not.

[trilarian]

First 1 hour of 1080i is 8.5gb not what above person said.

Standard Definition is not 1080i... :rolleyes: PVR-150 does not record HD, and runs roughly 1.xGB per half hour.

Finally, your software raid 0 has a hidden gotcha.

That is why I stated I backup stuff I wish to keep to DVD-DL, and don't bother with stuff I don't. Running software RAID is free, and a pack of 50 DVD-DL (that is 425GB of storage) cost me roughly $40 - $50. I also have access to 100% of my drive space since none is duplicated as backup. Hardware RAID 5/6 is a nice setup, and often used for high end database/file servers, but really is not needed for a home Myth system.

[cybernard]

Standard Definition is not 1080i... :rolleyes: PVR-150 does not record HD, and runs roughly 1.xGB per half hour.

Your correct, I made a SD vs HD mistake.

That is why I stated I backup stuff I wish to keep to DVD-DL, and don't bother with stuff I don't.


Congratulation, your in the 0.1% of the population that backup, I am talking to everyone else who is way to lazy. Even though I take good care of my DVD's they always end up scratched, guess I am unlucky that way.


Running software RAID is free, and a pack of 50 DVD-DL (that is 425GB of storage) cost me roughly $40 - $50. I also have access to 100% of my drive space since none is duplicated as backup.


That part is correct, but magnify the storage of the DVDs and cost against my 3200gb of data and growing. If 1 drive fails in your setup your lose it all. Yes, you have backed it up, :) again pat yourself on your back for that :) , but imagine the hours it would take to copy it all back.


Hardware RAID 5/6 is a nice setup, and often used for high end database/file servers, but really is not needed for a home Myth system.

RAID 5/6 is nice is the understatement of the decade speaking as the owner of one. :)

I have lost 400gb of data twice due to depending on software RAID 0 and/or the linux equilivant of dynamic disk. I was very very said. :(:(