[mythtv-users] Multicasting BE Recordings - now can do!

Tortise tortise at paradise.net.nz
Mon Jan 11 01:58:50 UTC 2010


----- Original Message ----- 
From: "Nick Rout" <nick.rout at gmail.com>
To: "Discussion about mythtv" <mythtv-users at mythtv.org>
Sent: Monday, December 14, 2009 8:54 PM
Subject: Re: [mythtv-users] Any FE to Many PCs - LAN Content Simulcasts withVLC Multicasting


On Sun, Dec 13, 2009 at 12:05 PM, Tortise <tortise at paradise.net.nz> wrote:
> GOAL: Move to integrate HD into an Any to Many Model.
>
> I've been trying to achieve "any FE PC to many PC simulcasts of live and
> recorded content" for some time in the new HD world.
>
> I have enjoyed this for some time in the SD World using a dual channel
> modulator that puts out a UHF Channel stream as taken from a
> SD AV receiver composite output feed as also displayed on the respective
> TV's (used effectively just as Monitors) one in the Lounge
> and
> the 2nd in my room where this kit resides. That old world is therefore a 2
> to many situation which was ok, any to many would be
> even better, especially as I
> move to have a PC in most rooms.
>
> Why do this? The typical TV program model is to sit down in one room and
> watch the one screen. Sometimes I like to watch something
> on the move between a number of rooms - a good example might be in the early
> evenings I might want to watch something, cook some
> stuff and work on something in the workshop - roaming between those rooms.
>
> With the SD model that was cool, a quick flick on of the (old!) TV in each
> room and tune the respective channel UHF and the stream
> is replicated, be it live tv, tivo, mythtv, dvd, radio, whatever....
>
> And HD? Not so easy! Some ways to do this have occurred to me:
>
> Coaxial Transmission:
> HD Modulator
> If there was an economic HD modulator equivalent I'd also need HD tuners in
> each location. Not so good an idea.
>
> Existing SD Modulators
> To achieve this I need to descale the HD video to SD, which can then be fed
> into the existing network. Quality descaling would
> result in a quality SD experience in most rooms, this would be acceptable.
> 16:9 HD would potentially be seen on both 4:3 SD TV's
> and 16:9 HD TV's. But getting SD from HD from each myth box? Not so easy.
> The myth boxes that I am more likely to want to see
> broadcast locally feed their displays with component. Hmmm.
> I could use a VGA in / Component and Composite Out box however the quality
> of this conversion seems somewhat risky, one would be
> required from each set of Mythtv
>
> MultiCast with VLC:
> This might work, I figure I'd use VLC as the myth media player and set it to
> multicast at the same time using the appropriate
> command line. Then any PC on the network could tune the appropriate
> multicast stream...any pc...and bingo, multicast! Each
> multicast client would need to have enough puff to play the HD streams.
> (This means they need to be higher spec CPU's as can't use
> vdpau) I've tested VLC multicast and it works well out of the box. Now I
> just need to set it up...and test some more.... Anyone
> thought of this, tried this or any comments?
>

>mythtv is a upnp server
>vlc can act as a upnp client
>vlc can act as a multicast server

>solution: find a mechanism to star vlc as a upnp client to the mythbackend, and simultaneously multicast it to your lan.

Well that didn't work as uPnP was missing....  until today...

The latest VLC update (I think via http://ppa.launchpad.net/mythbuntu/repos/ubuntu) just added in uPnP support.

It reads my mythtv BE via uPnP but seems to crash playing stuff.....every step is small....!

However.......if I click stream........it streams a recording direct from the mythBE...and plays it also!! All be it with an 
incorrect aspect ratio on the server(!)  Setting aspect ratio to 16:9 seems to fix this.

Clients are correct in their aspect ratio.

CPU with a 576i H264 stream is about 30-40%.  (3.16G C2D)

Great idea Nick thanks.  (Anyone want to check out audio sync / echo issues on recordings easily can now...)

Kewl! 



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