[mythtv-users] mythtv-users Digest, Vol 36, Issue 176

[Jeff Simpson]

On 3/28/06, j.mcdowell at mcdowelltribe.com <j.mcdowell at mcdowelltribe.com>
wrote:
>
>   19. Equipment setup q's from a noob. (j.mcdowell at mcdowelltribe.com)
>   22. Re: Equipment setup q's from a noob. (Jeff Simpson)
>   26. Re: Equipment setup q's from a noob. (Robert Johnston)
>
> > At the moment, there is no smart card access setup for myth, so you
> might
> > need to go another route, perhaps a password or user-account-based
> system.
>   One could use bio metrics, I know that is well supported under linux
> as a whole, however I am not familiar w/ MythTV yet and therefore it
> may not work.  It is however the very last of my concerns and something
> I would be willing to help to develop if it doesn't exsist.  Again this
> is the last thing I am worried about as punishment is always an option.


The MythTV Frontend is just an application that loads and displays to the
TV. If you have experience with biometric sensors, you could do whatever it
takes to get that working under linux and simply use that as the password to
allow access to the system, and have MythFrontend start automatically after
that. You might not even have to incorporate it into myth at all, so long as
you didn't want anything more than an allowed/not allowed flag (ie, that
method wouldn't have time limits, restricted channels, etc, as those
features don't exist in myth).


  I can always break them apart, however it is important to me to have
> FULL feeds and not "Digital Zooms".  I.E. Some security system cards
> will support 5 pics on one screen while they record.  However, if one
> wants to play them back for any reason they are of very poor quaility.
> So as long as MythTV has good support for separate systems streaming
> back and forth w/ good quality I am ok w/ that.


They would be full feeds. The PVR-500 card records at 720x480 (NTSC), and
will be at least as good as a VCR would be. Any more than that resolution
would require digital cameras anyway (which may be a better choice, but you
mentioned that you already have the cameras.)


>   I currently have 500 GB in my PC and 2 Gb ram, so space is not an
> issue w/ the cost of drives falling the way they have.  With the right
> rebate special I can get a TB for $220.00.  Those are SATA drives btw.
> Ram, same thing, so cheap w/ the right rebate it's sick.
>   So a 2 TB SATA Raid would cost me 440.00, and again I am ok with
> that.  However, if I separate the boxes I should need 1.5 TB in the
> security streamer.


You shouldn't have to split the boxes by purpose, just by physical number of
cards / drives. It may make sense to have all the drives in one server, and
have the capture cards shared between the two. You will want all the
recordings to be on one partition, either local or NFS.

> Picture-in-Picture should work for the security cameras the same as TV
> > inputs. Not sure if there is any support for an all-at-once mode.
>    I am willing to allow certain developer access to my system if I
> build it, to develop features on worthy hardware.


I don't know if developer access would be the limiting factor for the
development, it's probably just a matter of which features are likely to be
used often. As a workaround, it is fairly trivial to just play the mpg files
directly while they are recording using mplayer. You can have 7 mplayer
windows open on the same screen and resize / open / close them as you need.
Won't be as pretty as the PIP on myth, but it may work better this way.

> This one will be tough - I don't know about your internet connection, but
> > mine can't handle a 2.2Gig/hour stream. You need at least 54mbps
> wireless or
> > 100mb wired ethernet to view live. Transcoded you might be able to
> stream
> > over a lower connection, but it wouldn't be a live feed.
>
>   Again, I SHOULD be able to mod tihs to get a semi live feed, a few
> mins delayed.  And if I want to review video over the web, well that's
> a little ambitious.  If the problem is that bad, I can come home.


It should be possible to have an application grab frames from an mpeg on
request, and thus you can have a "live" view of the camera, updated every
30-60 seconds or so, depending on how you set it up.

  Again I have no issue w/ making a box for each TV, I guess the
> question remains will a celeron 1.2 GHZ work w/ 256 MB memory and if I
> am lucky I may have a pci slot in these things.  If not I can build
> what ever I need.


a celeron 1.2 should work quite nicely for a frontend machine. If they have
TV-Out that is linux-supported and 100baseT ethernet, you may not even need
to use that PCI slot.

  I have no idea just yet how mythTV works, I am just starting to read
> about it.


Basically you have a "Backend" which is where all the data storage and
recording takes place, and you have a "Frontend", which is where the viewing
happens. You can have any number of backends and frontends, but as a rule of
thumb, it is good to have as many tuners as frontends, otherwise you won't
be able to use all of them to record or watch TV at once. The frontend
machines are used to schedule recordings, view recordings, etc, but the
backend is the one that actually records them, so any frontend can watch
what the backend has recorded.

To further confuse the issue, you can run multiple frontends on the same
machine, as well as running a frontend on the same machine you run the
backend on. It's a very configurable setup, the only thing that needs to be
connected between a backend and a frontend is a MySQL Database port, a
mythTV backend control port, and a port to stream the video. Additionally,
you may want to have NFS drive sharing to allow other access to recordings,
but it's not needed for just TV.

   Cost is an issue if it gets crazy, however, has anyone priced the
> cost of a security PVR latley ?  I couldn't get one for 6k that would
> handle all the feeds I want.  I have also seen cards that will handle
> up to 8 CCTV connections @ once.  I am still inquiring as to their
> usefullness.


I am curious how the cost compares between a CCTV card and a normal video
input card. CCTV is generally a lower resolution and black and white, so it
probably can be done for a much lower cost and bandwidth. If that card can
be interfaced with MythTV, that may be an interesting idea.

MythTV is more of a TV-Recording/Scheduling/Home entertainment box. The
"Mythical Convergence Box" as it was named for, a single system that
controls everything. I haven't heard of many people tying their security
cameras in there, so it's probably cheaper to get a dedicated security
system, but you will have a lot of flexibility and features with myth.

  I don't care about the quality on MOST of my cameras, however, the
> front of the house and the sides I want all but HI-DEF. :D


You should be able to record in as high a quality as the camera outputs, so
long as it is outputting in NTSC that the recording card can read.


>   I have thought about this, and they aren't flexable enough for me. So
> I have been thinking that a BASE Athlon 64 w/ 1 gig ram would be more
> than enough.  I can make this small enough to hide inside my
> entertainment center.  It's the BIG BOY w/ all the discs that HAS to
> remain in the basement.  So hopefully MythTV will use the master /
> slave thing VIA TCP/IP so there isn't any let down in signal quality.


Exactly what it does. The Master/Slave thing is actually for just the
backends, and you would probably want both of those in the basement. The
Backend/Frontend concept is what will allow you to transfer all the video
digitally without signal loss. You leave the Backend in the basement with
all the loud discs and TV tuners and just run Cat5 to each of the frontend
systems (or wireless G, but I suggest Cat 5 if you want a robust system).

  Again this is something I would be willing to "Develop" once I have
> an understanding that is better than what I have now.  I think I relly
> should have just built one before posting here.  So I beleive that will
> be my next step.


A good place to start would be to pick up a single PVR-150 or PVR-500 and
set up a linux system with MythTV around it. You can run the frontend and
backend on the same system to try it out, and add on other frontends as you
go (laptop, etc. Any system can be a frontend if it's >700Mhz or so, has a
fast ethernet connection, and can run linux. TV-Out is good if you want to
actually put the video on the TV, but you can watch on a monitor, too). Once
you have a single system set up, you can easily scale up to the number of
tuners and drives you need and keep adding frontends as you go.

 - Jeff
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