Too much red in leds

[jonnieboyrevel]

Hi all,

Firstly I'd like to thank gkaindl, this is an great project.

I've got everything set up and working, my issue is that there appears to be too much red in the leds. Yellows are a bit too orange, as is skin tone.

I've tried changing gamma levels but without much joy.

Can anyone advise me of the best way to correct this?

Thanks in advance.

Jonathan

[Phil1988]

This will definitely help you:

http://www.forum-raspberrypi.de/Thread-ambi-tv-farbwerte-ambi-tv

If you dont speak german go and translate the page with google translate:

[jonnieboyrevel]

Ok thanks, I'll have a look.

[amroibrahim]

@jonnieboyrevel what LEDs do u have? 52 per meter version?

[jonnieboyrevel]

Hi amroibrahim,

I have the 32 per meter LPD8806 leds.

Thanks

Jonathan

[jonnieboyrevel]

Apologies for my lack of Linux knowledge, I'd never used it before this project.

I've downloaded the zip file from the post but assumed I'd just replace the files and then use make again. However, if I try and run make I get an error.

I assume I'm missing something obvious but don't really know enough to know what it is. It doesn't help that Google translate doesn't do a great job on the post...

Can someone explain how to use the files from the linked post?

Any help would be greatly appreciated.

Jonathan

[amroibrahim]

What does the error say? I do remember compiling the given code before with no issues.

[Phil1988]

its important that you download this zip: http://www.activehitzclan.de/Volle/ambitv.zip

other zip files in this thread are for WS2801 etc..

just override the existing files and then run make.

nothing else needed.

after that you can adjust color values. if you start ambi tv from terminal it will work directly if it autostarts then you must adjust with a keyboard connected to the pi

[jonnieboyrevel]

Ok thanks, I'll have another go. The error was something to do with the date, If it happens again I'll make a proper note of it.

As a thought, I didn't update my PI at all after getting ambi-tv working. I'm still running it with 2013-07-26-wheezy-raspbian, would that make any difference?

[nickmazz]

Not sure really.

On Jan 8, 2014, at 12:11 PM, jonnieboyrevel notifications@github.com wrote:

Ok thanks, I'll have another go. The error was something to do with the date, If it happens again I'll make a proper note of it.

As a thought, I didn't update my PI at all after getting ambi-tv working. I'm still running it with 2013-07-26-wheezy-raspbian, would that make any difference?

— Reply to this email directly or view it on GitHub.

[alexeymohr]

Could someone possibly post a copy of the modified lpd8806-spidev-sink.c file where the colors are NOT reversed? I have these LEDs, and my colors are assigned correctly, but I'm having trouble figuring out how to modify lpd8806-spidev-sink.c file to undo the color reversal that was done by the person over at www.forum-raspberrypi.de

Thanks in advance!

[amroibrahim]

@alexeymohr a simple way to do it is to go to lpd8806-spidev-sink.c and go to line 180. there you should see r then on line 181 g and on line 182 b. just changing there order in those lines should change the order of the output. (for example if u want to switch the output that is for red to the blue switch r and b letters so line 180 would be b and line 182 would be r) hope my English makes sense.

[alexeymohr]

When I look at lines 180, 181, and 182, I see this:

}

static int

Down at 186, 187, and 188 I see this:

int r, int g, int b)

Is that the section you are referring to?

[Phil1988]

The reported problem (too much red) must be an overall problem.

I tested two grabbers (fushicai chip and STK 1160) and both show a too red grabbed picture. So this problem is caused by the grabbers or their drivers..

To your point: I dont know at the moment and cant have a look

[amroibrahim]

@alexeymohr yes, kind of strange u have them in different lines.

[alexeymohr]

Cool, I got the colors properly re-ordered in the lpd8806-spidev-sink.c file. I ran this re-compile, and the additional controls for overall brightness and individual color brightness are very handy.

Still, the colors themselves are a bit "off." I created several color test stills that I played with an Apple TV's picture slideshow function to see just how close the LED colors are to what I'm showing on screen. The hue of the colors is definitely a bit off, especially with blue and green. Adjusting the individual color gamma doesn't really help things, because that's just a matter color brightness. The problem is the interpretation of color hue.

Does anyone know of any way to adjust hue?

[sami-mw]

I have not read through all the history on this issue so I don't know if the OP's problem was solved but I had the same issue and it turns out it was the HDMI to composite converter. This is the one I have: http://www.amazon.ca/Sanoxy-HDMI-Composite-S-Video-Converter/dp/B0047PDBP0/ref=cm_cr_pr_pb_i and it overheats really badly. If you look at the signal that the raspberry pi receives (by running mplayer or plugging the composite back into your TV) and you see a lot of red stripes which increase as you use the converter you probably have the same issue. To solve this I opened the box of the converter and attached heat sinks to all the chips. This solved the red stripes issue, I hope this is helpful to someone else.