[mythtv-users] Bob's Huge List of Questions [Was: 0.22 annoyances]

Mark Small msmall at eastlink.ca
Wed Jan 6 11:21:43 UTC 2010


On January 5, 2010 19:58:09 Bob Cunningham wrote:
> On 01/05/2010 07:25 AM, Johnny wrote:
> >> His opinion surprised me.  In short, he said: "Put all your work into a
> >> feature-rich UPnP backend, then get a SageTV or Popcorn or similar media
> >> box for each TV."  From the perspectives of cost and ease-of-setup, this
> >> advice seems logical.  If I can get a box that's just smart enough to
> >> let me to access MythWeb, then it would seem I don't really need a
> >> MythTV frontend, and thus wouldn't need an HTPC.
> >>
> >> Comments?  Reactions?
> >>
> >> What would the best Media Player box be, assuming it would be talking to
> >> a MythTV backend?
> >>
> >> If this strategy seems prudent, then next step would be to craft the
> >> best bang-for-the-buck MythTV backend, which I assume would be a vastly
> >> simpler problem to solve (a 3 watt PlugComputer + HDHR?).  In which
> >> case, I'll not hijack this thread, and will start another thread for
> >> that subject.
> >
> > I don't agree. Going with UPnP device will limit your ability to use
> > some of the best features of MythTV. You would generally need more
> > than a 3 W plug computer for the backend, although not too much more.
> > You need disks, a CPU that can handle the database, commercial
> > flagging, etc, and you want to have a good network (I would go with 1
> > Gbps if I was starting out). The idea with a backend only machine is
> > that it doesn't need to be pretty or quiet. You can put all the disks
> > you need in it, etc, and then just stick it somewhere where you don't
> > see it or hear it.
> >
> > In the past it would have made more sense to go with something like
> > that popcorn hour, but now you can get a variety of small, quiet ION
> > based frontend machines for approximately $200. So they will have
> > basically the same footprint as a popcorn hour, but you get a full HD
> > capable frontend. So you get a full frontend that can do commercial
> > skip, time stretch, scheduling, etc. Also you can run other things
> > like XBMC or Boxee on there if you like. I don't see a compelling
> > reason to go with a UPnP frontend at this point.
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
> Last night I searched for ION boxes, and was pleasantly surprised: 9400M
> graphics +1.2 GHz CPU for US$200!  Power consumption still seems massive
> compared to the SageTV-type boxes, but it's a lot less than a regular
> PC.  And, yes, the cases are tiny.
>
> I suppose my initial joy at the thought of using something like a SageTV
> box was simply due to the fact that I'd not have to do any significant
> hacking to get instant functionality.  But with a MythTV frontend, once
> the first one works, cloning will be easy.
>
> After taking a quick look at the entire *minimal* processing chain from
> the cable TV to the disk and to the TV, the only part that always
> requires significant CPU horsepower seems to be SD compression (the vast
> majority of my channels are still SD).  A quick check shows it uses
> about 25% of a 3 GHz Xeon core, meaning it could saturate a 1 GHz
> single-core CPU, especially with multiple SD tuners.
>
> Are analog tuners with hardware compression worth it?  Do any
> USB/Ethernet analog tuners support SD compression?  (I haven't found any
> via Google.)   Can I somehow use the GPU for SD encoding?
>
> The next most CPU-intensive operations seem to be transcoding and
> commercial-flagging.  Since this does not need to be done in real-time
> on the backend, this means I'd simply have to use the TV tuner for
> LiveTV.  An acceptable trade-off, since I seldom watch LiveTV.
>
> Let's say I get an analog tuner with hardware SD compression (I *really*
> wish the HDHR had two of them).  Can I do transcoding and flagging
> without an FPU?  Can I consider using an ultra-low-power ARM CPU on the
> backend?
>

There's a fellow around who is using a sheevaplug for his master backend.  
Apparently it works great but it without and FPU commflagging/transcoding is 
just too slow to be feasible.  He uses the sheevaplug as a master backend 
that does no recording that wakes up a slave backend to do the recording.

Have a look here:
http://computingplugs.com/index.php/Sheeva_Plug_as_a_MythTV_master_backend

You could do analog/SD recordings on a sheevaplug/equivalent with a Hauppauge 
USB-PVR2.  Its a hardware encoder with a USB connection.  They show up on 
ebay now and then.  Driver info is here (Its in the recent kernels):

http://www.isely.net/pvrusb2/pvrusb2.html

Hope this helps,

Mark

> TIA,
>
> -BobC
>


More information about the mythtv-users mailing list