FoodServiceIT
Posts: 4
Joined: Thu Feb 27, 2014 6:28 pm

Multiple Video Displays

Thu Feb 27, 2014 6:54 pm

Hello everyone, I have never used Raspberry Pi before but it was suggested by a friend that for the project I have coming up, that this would be a good way to go. I am looking for some info on if this is possible or if there would be a better way to do it.

Here is what we are trying to do:

We have 9 sites which require anywhere from 1-6 displays per site.
5 elementary schools
2 middle schools
2 high schools
-------------------------------------------------------------------------------------
The current options are provided by Nutrislice are:
There are various hardware configurations that are compatible with our product, but they can be broken down into two basic configurations:

(1) (Wired One to one) One computing device connected to each screen

(2) (Wired One to multiple) Single computing device attached to multiple screens via (a) a single video output, split with VGA, DVI or HDMI splitter/booster hardware (depending on the output) or (b) multiple video outputs (with video signal boosters for significant distances (VGA is more tolerant of longer distances without boosting, but is a lower quality signal)).

(3) (Wireless via Chromecast) Wireless transmission via Google Chromecast dongles. This requires one Google Chromecast device per screen and the presence of a reliable, high-speed, high signal strength wireless local area network to connect the Chromecast device to a computer on the local area network.

**********************
or (this is the one I'm having some trouble with)
(4) Use 3-9 virtual servers (one for each school level / or one for each site) and have the VS's provide the video feed to the displays at the different sites.
-------------------------------------------------------------------------------------
The company providing the digital signage answered this when I suggested using virtual servers for this:

"Virtual servers would be fine if you have a mechanism to get the video output from the desktop of each virtual server onto the screen at each respective school. However, I'm not familiar with such a mechanism (but admittedly, I'm not a video hardware expert). If there is one, we're interested to learn about it, since that could be a cost-saving mechanism, as you note.

The reason we generally have one CPU per screen or at least one per school with split video output to each screen is to get the desktop video signal (we essentially run in a full screen HTML5 browser) to the TV."
-------------------------------------------------------------------------------------

Any thoughts, insights or suggestions are greatly appreciated.
Thank You

ghans
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Location: Germany

Re: Multiple Video Displays

Fri Feb 28, 2014 8:34 am

Are those displays running videos or are they displaying mostly
static information ? What kind of hardware and software
is usually used in scenario 1 ? "computing device" is a very
vague term. Is it a special browser ? Special browser-plugins ?
Something else altogether ?

ghans
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jamesh
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Re: Multiple Video Displays

Fri Feb 28, 2014 9:01 am

Not exactly sure of the requriemnts, but i woudl go for 1).

Attach a Raspi to each screen, connect Raspi to ethernet. Have a central school server which is command/control/storage, and tells each Raspi what to do. The Raspi can then stream video or whatever from the main server.

Or CC could send videos to each Raspi to store locally for playback, although not much of a benefit over streaming I don't think.

Raspi can display 1080p30 video, so that should be no problem.
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FoodServiceIT
Posts: 4
Joined: Thu Feb 27, 2014 6:28 pm

Re: Multiple Video Displays

Thu Aug 28, 2014 10:24 am

The problem with 1 to 1 is the cost of all of the new towers (as we just purchased 26 new systems for the managers & office staff) so money is limited.

The display's would be fed a static revolving display of still images via chrome browser.
example: http://www.nutrislice.com/school-lunch- ... gnage.html

Jamesh, any suggestions on the best place to get a bulk order of Raspi's and their average price?

Thanks

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RaTTuS
Posts: 10381
Joined: Tue Nov 29, 2011 11:12 am
Location: North West UK

Re: Multiple Video Displays

Thu Aug 28, 2014 10:48 am

FoodServiceIT wrote:The problem with 1 to 1 is the cost of all of the new towers (as we just purchased 26 new systems for the managers & office staff) so money is limited.

The display's would be fed a static revolving display of still images via chrome browser.
example: http://www.nutrislice.com/school-lunch- ... gnage.html

Jamesh, any suggestions on the best place to get a bulk order of Raspi's and their average price?

Thanks
don't use chrome to display a static image :roll:

http://cpc.farnell.com/raspberry-pi/ras ... dp/SC13456
is about the best YMMV
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JizzaDaMan
Posts: 66
Joined: Sun Apr 07, 2013 2:14 pm

Re: Multiple Video Displays

Thu Aug 28, 2014 11:23 am

I recently did a project like this for a school play, where I had 4 pis, each wired up to an individual display. The display would then play a video or show an image, or display the webcam. All images and videos were stored on the individual pis. I used sockets to send a signal to the pi which would tell it what to do. Scripts stored on the pi would then be run to do the right thing. I used omxplayer and feh. The remote control of omxplayer required using pipes which were very buggy. I tell you what... It was an organisation nightmare and it didn't work very well (Although we did pull it off :) )

Moral of the story:
If you want your displays to be synchronised, Ethernet is not the way to go.
For playing videos omxplayer is fine, so long as all your videos run through to the end and you don't need facilities to pause/play, or quit mid video, because that can get pretty messy. If this is the case, consider writing your own video playing script in python.
Sockets are not worth the effort - use SSH

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topguy
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Re: Multiple Video Displays

Thu Aug 28, 2014 11:57 am

If chrome can cast to Chromecast when run on a virtual server, then I see a possible combination of #2, #3 and #4.

Virtual server running Chrome, casting to a Chromcast which is connected to a HDMI splitter where that is practical.

Alternative is to replace Chromecast with Raspberry running Miracast/Piracast. Its unfortunate that both solutions require wireless, but for this usage one can have arguments both for (easy placement, no cables) and against ( unreliable connection speeds) using wireless in such a setup.

FoodServiceIT
Posts: 4
Joined: Thu Feb 27, 2014 6:28 pm

Re: Multiple Video Displays

Thu Aug 28, 2014 6:49 pm

RaTTuS wrote:
FoodServiceIT wrote:The problem with 1 to 1 is the cost of all of the new towers (as we just purchased 26 new systems for the managers & office staff) so money is limited.

The display's would be fed a static revolving display of still images via chrome browser.
example: http://www.nutrislice.com/school-lunch- ... gnage.html

Jamesh, any suggestions on the best place to get a bulk order of Raspi's and their average price?

Thanks
don't use chrome to display a static image :roll:

http://cpc.farnell.com/raspberry-pi/ras ... dp/SC13456
is about the best YMMV

it's not a single static image, it runs off the nutrislice website with a slide presentation, the company recommends chrome as they have had problems with IE.
Last edited by FoodServiceIT on Thu Aug 28, 2014 7:20 pm, edited 1 time in total.

FoodServiceIT
Posts: 4
Joined: Thu Feb 27, 2014 6:28 pm

Re: Multiple Video Displays

Thu Aug 28, 2014 6:55 pm

JizzaDaMan wrote:I recently did a project like this for a school play, where I had 4 pis, each wired up to an individual display. The display would then play a video or show an image, or display the webcam. All images and videos were stored on the individual pis. I used sockets to send a signal to the pi which would tell it what to do. Scripts stored on the pi would then be run to do the right thing. I used omxplayer and feh. The remote control of omxplayer required using pipes which were very buggy. I tell you what... It was an organisation nightmare and it didn't work very well (Although we did pull it off :) )

Moral of the story:
If you want your displays to be synchronised, Ethernet is not the way to go.
For playing videos omxplayer is fine, so long as all your videos run through to the end and you don't need facilities to pause/play, or quit mid video, because that can get pretty messy. If this is the case, consider writing your own video playing script in python.
Sockets are not worth the effort - use SSH
Thanks
In sync would be good, however, they don't have to be.
The screens would display content for their school level (Elementary, Middle, High) and each cafeteria has multiple displays.

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RaTTuS
Posts: 10381
Joined: Tue Nov 29, 2011 11:12 am
Location: North West UK

Re: Multiple Video Displays

Fri Aug 29, 2014 8:04 am

http://www.raspberrypi.org/forums/viewtopic.php?t=40860 is what you will probably need to look at TBH
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

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