V4L2: Add shutdown detection

The problem is, that the picture is coming from the HDMI2AV converter and not from the grabber. So the HDMI2AV converter is sending a rainbow or blue picture and the grabber thinks it is a valid signal.

As suggested, we can define an area where the threshold is applied. Then you can define the area for a blue stripe and this will be used for detection

As another rainbow no-signal sufferer here, what about adding audio capture support to disable LED output after x-seconds of no captured sound?
Has the added benefit of disabling output when my blueray/mediabox screensaver kicks in.

Audio capture is not so easy, because we have no reliable always available api in linux. There is alsa, jack and pulseaudio. We have to implement all of them to get this feature work everywhere. Then comes next prob, hyperion is often used on raspi and there is no audio in (extra hardware is needes).
I'm sure we will integrate audio in feature, because its needed for audio to lights ....

Since the shutdown issues are mainly on V4L2 capture setups, I would assume that most capture devices also have audio inputs. Helps on the raspberry pi at least.

For the time being, I'm going to see if I can cobble together a transistor on a 555 timer, taking a reset input from my TV's optical audio out. Shut off power to the LED string after x-seconds of no signal.

Take audio from grabber is just recording from an alsa device. So we have the problems described. It is possible to tinker with rpi gpio or arduino to detect active sound, but this solution is not the best.

maybe you can just take kind of a "screenshot" of the "no-signal-image" and save this as setting to recognize when there is no signal?

To complex, a god solution is already suggested some post before.

'we can define an area where the threshold is applied. Then you can define the area for a blue stripe and this will be used for detection'

Quote from redPanther

To complex, a god solution is already suggested some post before.

'we can define an area where the threshold is applied. Then you can define the area for a blue stripe and this will be used for detection'

Hello redPanther,

What is the status for the detection area feature for a "No Signal" image. I also have the problem that I bought 3 different HDMI to AV converters and they all produce a rainbow output when no HDMI input is detected.

Do you have any other suggestion related to this problem?

I've started implementation, but currently my time is limited and this feature is not highest prio.
So you have to wait .... if somebody wants to do the work, this is the point where to place to code
https://github.com/hyperion-proje…rabber.cpp#L789

Quote from redPanther

I've started implementation, but currently my time is limited and this feature is not highest prio.
So you have to wait .... if somebody wants to do the work, this is the point where to place to code
https://github.com/hyperion-proje…rabber.cpp#L789

Thnx for your answer. I like to help but i'm not a developer. So I will wait. Do you have a date when you expect it will be ready? And if you search persons to test the new function let me know.

hi friends, could you help me please?
My hdmi2av sends blue picture when no signal -
When I checked image in image editor, I found out that there is several pixel values e.g.:
18,71,255
19,73,255
20,71,255 etc

I tried various settings to set v4l2 grabber to display "no color" on LEDs when there is no signal detected (I found out these values are the most important):

// SMOOTHING CONFIG
        "smoothing" :
        {
            "type"            : "linear",
            "time_ms"         : 200,
            "updateFrequency" : 20.0000,
            "updateDelay"     : 0
        }
    },


    // V4L2 GRABBER CONFIG
    "grabber-v4l2" :
    {
        "device" : "/dev/video0",
        "input" : 0,
        "standard" : "PAL",
        "width" : 360,
        "height" : 288,
        "frameDecimation" : 1,
        "sizeDecimation" : 1,
        "priority" : 900,
        "mode" : "2D",
        "cropLeft" : 20,
        "cropRight" : 20,
        "cropTop" : 20,
        "cropBottom" : 20,
        "redSignalThreshold" : 0.9,
        "greenSignalThreshold" : 0.9,
        "blueSignalThreshold" : 1.0
    },

I tried different settings (red/green thresholds from 0.0 up to 0.9, frameDecimation - 2,8, disable smoothing) but I am not able to get it working when no signal detected. LEDs always are blue when no signal detected and not going to "black"/turn off state. What am I doing wrong please?

Set all values to 1.0 Then no signal should be detected permanently. Then start to decrease a value in 0.003 steps. E.g. start with red 0.997 decrease this value until a signal is detected.

Then take the value before signal was detected.
Do this again with green value. Blue should stay at 1

Btw only frame decimation have impact on signal detection (besides the 3 threshold values of course)

implemented! ... in hyperion.ng. More details here:
https://github.com/hyperion-project/hyperion.ng/pull/334
https://github.com/hyperion-project/hyperion.ng/pull/339

Quote from redPanther

Set all values to 1.0 Then no signal should be detected permanently. Then start to decrease a value in 0.003 steps. E.g. start with red 0.997 decrease this value until a signal is detected.

Then take the value before signal was detected.
Do this again with green value. Blue should stay at 1

Thank you!