Distributed Audio/Video Player


4 posts
by SimCS » Wed Apr 11, 2012 11:28 pm
I have an application in mind that pushes either the main or extended desktop of a Windows PC (probably a laptop) simultaneously to multiple RPis connected to either TVs or projectors, to form a distributed media presentation solution.

Many projectors now have network (incl wireless) interfaces, including the NEC NP1000 I have (an older model), but to create a multi-screen system with a mix of projector and TVs, NEC's own Image Express Utility software won't cut it, as (i) there's no TV that can receive the network media stream, and (ii) the Vista/Win7 version doesn't support extended desktop.

The PC will therefore do the screen image 'push' out across the network, and the RPis will receive the stream, decode it and output the resulting audio+video vis the HDMI port. I need the software for both sides of the solution.
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by androssofer » Thu Apr 12, 2012 3:30 pm
I am not sure about the extended desktop part. But the remote viewing of the desktop could be achieved using VNC.

You would simply set up a VNC server on your laptop then set the raspberry Pis to listen for the server on the network. When it is active display the server output on the screens...

pulse audio could be used to carry the sound, using the same principles for VNC. this would allow a single server for audio and video.

I am however uncertain about the implementations of VNC and pulse audio on windows.. As i run a 100% Linux network...
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by jsparry » Wed Apr 18, 2012 4:09 pm
Don't mean to hijack the thread but I also had a very similar/same idea.

For work we use status screens with various monitoring data (e.g Nagios etc). On multiple desks around the office.

Currently I use the Cat5-e in the wall as a VGA cable. (£2 VGA to RJ-45 converter on each end) (And of course the the quality is very poor but just about does the job, just! so can't justify buying expensive VGA to Ethernet senders and receivers due to the amount of screens we have.)

So my idea was to stick a Pi to the back of the screen and allow the screen of the server to be displayed. (possibly using VNC as androssofer suggested.)

However this got me thinking it would be possible to make a Network projector server out of the PI. For Board room and meeting rooms etc.. To convert an old projector into a network projector. Using something along the lines of Microsoft's connect to Network Projector feature that's in Vista and Win 7.

However I far as i can tell windows projector feature will only work with Windows CE and was unable find the protocol spec anywhere to even workout if its possible to create a Linux based server alternative.

Ideally wanted the end user experience to be very easy to use. C-Level (CEO,COO,…) kind of IT skill level. Hence why VNC was not ideal.

But wondered if anyone else had any other ideas how this could be accomplished.

Jetto
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by jordi » Thu Apr 19, 2012 1:43 pm
In my workplace we use a propietary solution that does a similiar thing.

http://www.justaddpower.com/pr.....gory_id=16

This device gets an HDMI as imput, encodes it in h264 sends on the network to a multicast IP. Then you can have an arbitrary number of client devices that subscribe to the stream on the multicast IP decode the h264 and output it on an HDMI port.

In the end raspberry pi has a similar hardware than the renders on this setup.

We were thinking about VNC and similar software but in the end those things don't look well when you have to show videos.

One could have a hardware h264 encoding card on a pc and use it to generate the desired stream and publish it on a multicast IP. Then use several raspis to get this stream and decode it.
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