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I try to display (multiple) webcams on a hdmi screen with my Raspberry Pi B.

At first I used (since some month ago) OpenCV solution for 2x C170 Logitech Webcam -> works flawless (5-6fps).

Now I want to upgrade my system to 4 webcams -> OpenCV performance breaks down to 0.5fps.

Therefore I installed a new Raspbian Version + mplayer and excecuted rpi-update / apt-get update + upgrade.

mplayer works fine with 3-4 fps with all 4 Webcams parallel (enough for me).

But the color of the Cam's is total off.

Someone has a solution?

How it is How it should be

lsusb output:

Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 017: ID 046d:c045 Logitech, Inc. Optical Mouse
Bus 001 Device 018: ID 046d:082b Logitech, Inc. 
Bus 001 Device 019: ID 046d:c223 Logitech, Inc. G11/G15 Keyboard / USB Hub
Bus 001 Device 020: ID 046d:082b Logitech, Inc. 
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
Bus 001 Device 004: ID 05e3:0605 Genesys Logic, Inc. USB 2.0 Hub [ednet]
Bus 001 Device 014: ID 046d:082b Logitech, Inc. 
Bus 001 Device 015: ID 046d:082b Logitech, Inc. 
Bus 001 Device 016: ID 05e3:0605 Genesys Logic, Inc. USB 2.0 Hub [ednet]
Bus 001 Device 021: ID 046d:c226 Logitech, Inc. G15 Refresh Keyboard
Bus 001 Device 023: ID 1307:0165 Transcend Information, Inc. 2GB/4GB Flash Drive
Bus 001 Device 022: ID 046d:c227 Logitech, Inc. G15 Refresh Keyboard
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  • I have exactly the same issue as you do. I haven't tried to find a solution yet but will be watching here for answers. If we don't find any, maybe we can pull resources if we need to resolve ourselves.
    – Kolban
    Commented Apr 13, 2015 at 18:03
  • This question is to broad and has very little to do with Raspberry Pi. It is more about hardware and software issues that can happen on any OS
    – Piotr Kula
    Commented Aug 27, 2015 at 7:26

1 Answer 1

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Have you tried adjusting mplayer at all? From man mplayer:

(The following keys are valid only  when  using  a  hardware  accelerated  video  output  (xv,
(x)vidix, (x)mga, etc), the software equalizer (-vf eq or -vf eq2) or hue filter (-vf hue).)

      1 and 2
           Adjust contrast.
      3 and 4
           Adjust brightness.
      5 and 6
           Adjust hue.
      7 and 8
           Adjust saturation.

That's a pretty elaborate man page. Probably daunting at first but if you are doing things with 4 cameras, no doubt worth a read.

From the looks of things the hue and saturation need serious adjustment.

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  • 1
    I tried different settings, here is what i used: mplayer -fps 3 -nosound -nocache tv:// -tv driver=v4l2:width=320:height=240:device=/dev/video0:outfmt=YUY2 and experimented with :brightness=XX :saturation=xx etc. commands. No really good result.
    – Matyro
    Commented Apr 13, 2015 at 16:45

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