View source for VLC HowTo/Make a mosaic

{{howto| set up a mosaic of a few videos or stream like a TV portal}}

==VLC mosaic howto==

This is a small example about how to use {{VLC}} to create a mosaic. What we basically want is a video mosaic mixing 3 video channels (channels 1, 2 and 3) on a background image (background.png) and streaming the resulting video on the network. Note that we will also be streaming the 3 sound tracks from channels 1, 2 and 3 in the same mpeg-ts stream.

Starting with VLC 0.8.5-test2, the http interface features a "Mosaic wizard". You might want to use it if you have no knowledge of VLC command line usage.

http://people.via.ecp.fr/~dionoea/videolan/mosaic1.png

Other neat examples :

[http://people.via.ecp.fr/~dionoea/videolan/mosaic2.jpg 12 video mosaic]

[http://people.via.ecp.fr/~dionoea/videolan/mos1.png 20 video mosaic]

[http://people.via.ecp.fr/~dionoea/videolan/mos2.png 20 video mosaic]

===Step 0===

Read the VLC streaming howto (chapters 3 and 5 concerning command line and vlm usage in VLC) : http://videolan.org/doc/

===Step 1===

Get VLC 0.8.4-test1 or newer and install it on your computer.

===Step 2===

You now have to get a background image. Many image formats are supported (JPEG, PNG ...).

You can also test it with VLC to see if it displays locally :
<pre>
./vlc --fake-file background.png --fake-aspect-ratio "4:3" fake:
</pre>

===Step 3===

You now need to configure VLC to get the 3 source streams and blend them on the background image.

The vlm configuration file looks like :

<pre>
new channel1 broadcast enabled                                                       
setup channel1 input udp://@239.255.2.60:1234                                        
setup channel1 output #duplicate{dst=mosaic-bridge{id=1,height=144,width=180},select=video,dst=bridge-out{id=1},select=audio}                                                         
                                                                                
new channel2 broadcast enabled
setup channel2 input udp://@239.255.10.200:1234
setup channel2 output #duplicate{dst=mosaic-bridge{id=2,height=144,width=180},select=video,dst=bridge-out{id=2},select=audio}                                                         

new channel3 broadcast enabled
setup channel3 input udp://@239.255.6.9:1234
setup channel3 output #duplicate{dst=mosaic-bridge{id=3,height=144,width=180},select=video,dst=bridge-out{id=3},select=audio}                                                         

new background broadcast enabled
setup background input fake:
setup background output #transcode{sfilter=mosaic,vcodec=mp2v,vb=10000,scale=1}:bridge-in{delay=400,id-offset=100}:standard{access=udp,mux=ts,url=239.255.12.42,sap,name="mosaic"}

control background play
control channel1 play
control channel2 play
control channel3 play
</pre>

Note that the source streams are network streams, which is likely to be the case if you're considering doing a mosaic.

===Step 4===

And now, the right command to launch vlc :

<pre>
./vlc --color -I telnet --vlm-conf ../mosaic.vlm.conf --ttl 12 \
 --fake-file background.png --fake-aspect-ratio "4:3" \
 --mosaic-width 360 --mosaic-height 288 --udp-caching 800 \
 --mosaic-keep-picture --mosaic-rows 2 --mosaic-cols 2 \
 --mosaic-position 1 --mosaic-order 1,2,3
</pre>

== Other examples ==

=== Dual webcam with alphamask ===

http://people.videolan.org/~dionoea/mosaic/dual-webcam.png

<pre>new isight broadcast
setup isight input v4l2:///dev/video0:width=320:height=240:audio-method=0
setup isight option v4l2-brightness=90
setup isight output #mosaic-bridge{chroma=YUVA,vfilter=alphamask{mask=../mask.png},width=320,height=240}
setup isight enabled

new logitech broadcast
setup logitech input v4l2:///dev/video1:width=640:height=480:audio-method=0
setup logitech output #transcode{vcodec=mp4v,vb=1024,sfilter="mosaic:marq{marquee='VLC dual webcam setup',position=8}"}:bridge-in:display
setup logitech enabled

new audio broadcast enabled
setup audio input v4l:///dev/dsp1
setup audio output #transcode{acodec=mp4a,ab=128}:bridge-out

control isight play
#control audio play
control logitech play</pre>

You can then launch it with:
 vlc --vlm-conf ../dual-webcam.conf --no-media-library --plugin-path modules -v --no-video-title --mosaic-keep-picture

The mask.png file is used to set transparency values on the isight camera (uses the png alpha plane). An example file to use is available at http://people.videolan.org/~dionoea/mosaic/.

==See Also==
* [http://people.via.ecp.fr/~dionoea/videolan/mosaic-diagram.png Small Diagram That Might Help]
* [http://people.videolan.org/~dionoea/mosaic/ VLC Mosaic related resources]
* [[MosaicExampleSetup | Example set-up of conference web-streaming with two grabber cards]]

==Appendix==
* [[Documentation:Modules/mosaic]]
* [[Documentation:Modules/mosaic-bridge]]
* [[Documentation:Modules/bridge-out]]
* [[Documentation:Modules/bridge-in]]
===Mosaic specific video filters===
* [[Documentation:Modules/alphamask]]
* [[Documentation:Modules/bluescreen]]