[mythtv-users] Raspberry Pi as a slave backend server

[Jay Harbeston]

On Mar 22, 2015 4:06 PM, "Dave MythTV" <dave.mythtv at gmail.com> wrote:
>
>
>
> On Sat, Mar 21, 2015 at 3:09 PM, jrh <jharbestonus at gmail.com> wrote:
>>
>>
>>> On Mar 21, 2015, at 12:56 PM, Dave MythTV <dave.mythtv at gmail.com> wrote:
>>>
>>>
>>> On Fri, Mar 6, 2015 at 8:22 PM, jrh <jharbestonus at gmail.com> wrote:
>>>>
>>>> I have experimented some using the raspberry pi as a slave backend
server and have had generally good results with caveats.
>>>>
>>>> Configuration:
>>>> Raspberry Pi Slave backends running v 27.4(dated in November)
>>>> NFS mount to the Master backend for the mythtv directories.
>>>> Hauppauge USB HVR-950Q tuner(1 only ) (configured only 1 virtual tuner
so only 1 recording)
>>>> I did not configure the analog side of the tuner, only the digital
part.
>>>>
>>>> Using a Raspberry Pi model B and B+:
>>>>
>>>> Able to record Standard Definition mpg video stream.
>>>> When attempting to record 720p or 1080i streams, there would
consistently be TFW taking to long errors.
>>>>
>>>> Using a Raspberry Pi 2 model B: (the quad core version)
>>>>
>>>> Able to record Standard Definition mpg video stream
>>>> Able to record both 720p and 1080i streams up to 15mbps!
>>>>
>>>> In summary, for 1 stream and a USB TV stick The RPi 2 is a viable
masterbackend with the above conditions. I didn’t try multiple streams off
the same real channel, but I suspicion the Pi 2 would be able to handle it.
>>>>
>>>> Note that I did not try analog recording as there are no analog NTSC
Over the air broadcast stations in the area and so I didn’t even try to
configure the analog side.
>>>
>>>
>>> Thanks for sharing this information!
>>>
>>> A few quick questions for you:
>>> 1) Which Linux distribution are you using?
>>> 2) I'm assuming this testing was with a wired network (and not a USB
wireless adapter)?
>>> 3) Do you have any thoughts on the source of the TFW errors on the Pi
1?  Such as, whether the TFW errors with the Pi 1 were related to the CPU
loading, pushing the data out across the network, or a limitation of the
USB system?  (Since it kept up OK with standard definition streams, I'm
wondering if the Pi 1 might be sufficient as a high-definition slave
backend if it recorded directly to a small local USB hard drive, or even to
its own SD card, and then did a non-realtime NFS data transfer back to the
master backend when the tuner was idle?)
>>>
>>>
>>> Keep us posted on how things go if you try multiple streams or multiple
tuners on the Pi 2!
>>>
>>> Thanks
>>> - Dave
>>
>>
>> I am using raspbian off the noobs image.
>>
>> You are correct, I just used wired network. I didn’t even want to try
going wireless.
>>
>> I didn’t even try experimenting using a local usb drive as that wouldn’t
fit my usage scenario, so are still all good questions.
>>
>> I will be staying with a single USB tuner for my needs, and Since I
started using the RPi 2 configured as above, I have had no TFW errors since
starting to use it!
>>
>> I have no plans whatsoever to try to use an RPi of any kind as a
frontend, however, they are very insteresting as a remote backend like I am
using. The pi 2 plus the hauppauge USB tuner are only using around 7 watts
while recording!
>>
>> By the Way, I noticed I goofed above when I said it was a viable master
backend. I meant to say it is a viable SLAVE backend.
>>
>> An experiment I might try sometime in the future is to have an RPi as a
masterbackend ONLY with no tuners(just define a dummy recorder). No
immediate plans to try that tho yet.
>>
>> Regards
>>
>
>
> Thanks for the reply.
>
> Remind me again what your usage scenario is?
>

I needed a remote tuner as you spoke about however I do have wired network
available. I don't think wireless will work very well.
>
> I'm considering a possible usage for myself with a remote slave backend
up in the attic, on a wi-fi connection, to allow for separate tuners
directly connected to separate directional antennas aimed at some of our
fringe stations from nearby cities.   Being co-located up in the attic
would allow the USB tuners to be directly connected to the antennas
(effectively 6 inches or less of coax), minimizing the cable loss and
removing the need for multiple additional long coax runs (and possibly
pre-amps) to the master backend/frontend in the living room.
>
> The Raspberry Pi would seem to be a good candidate for this, but if I end
up needing two or more Pi 2s to handle the separate tuners individually, I
might as well just stick a single x86 ECS LIVA up there instead as the
overall price and power consumption would be similar, and the setup would
be much simpler.   If one of the Pi 1 models could do the task for a single
HD stream, however, then even with multiples, the price and power figures
swing into their favor.  :-)

The pi 1 doesn't have enough 'grunt' to handle HD streams. When I tried it
I had a lot of TFW errors.  The pi 2 was fine with HD stream. I didn't test
was the multi tuners on the pi 2.

Regarding your remote additional antenna, why not try the hdhr tuners?

>
> And it's all in that interesting scenario where it would be easy to test
with experimentation, but if I try it and it doesn't work, the $$ "wasted"
on the Pis could have just bought the LIVA.    Hence the interest in the
details of what you've been testing!
>
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