Is there a way to record a video without a quick flash on the screen when starting and stopping the recording? #137

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1. EriFisher

   changed the title [-]Is there a way to record a video without it making a quick flash on the screen when starting and stopping the recording?[/-] [+]Is there a way to record a video without a quick flash on the screen when starting and stopping the recording?[/+] on Mar 24, 2017
2. garsdle commented on Apr 13, 2017

   

   garsdle

   on Apr 13, 2017

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   Are you trying to make something like this?
3. patthehuman commented on Apr 13, 2017

   

   patthehuman

   on Apr 13, 2017

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   I am getting the same issue when I start recording, the screen flashes. When I stop recording, the screen flashes again.
4. bevbomb commented on Apr 19, 2017

   

   bevbomb

   on Apr 19, 2017

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   I've been testing out a basic filter with recording and I'm seeing the same issue, it looks to be a focus issue because at the start of most my test videos I have a low lit dark video which fades back to the normal brightness
5. eliot1019 commented on May 25, 2017

   

   eliot1019

   on May 25, 2017

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   Would greatly appreciate it if anyone who solved this problem could share their solution.
6. bevbomb commented on May 25, 2017

   

   bevbomb

   on May 25, 2017

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   @eliot1019 I couldn't find a fix for this Unfortunately. I had to go back to the original GPUImage
7. EriFisher commented on May 25, 2017

   

   EriFisher

   on May 25, 2017

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   The fix for my motion recording was to use a timer. I think in your situations that don't seem as much motion based, just the flash is on everything is to cut out the beginning of every recording, which I believe you probably can do this losslessly. Just put label on the screen like when you first start recording, "ready" then after one second change it to " Recording" on the screen. That way you let the user know what is usable. I noticed this flash on every swift based camera framework, so it might be something with swift rather than GPUimage2. I also saw the flash on apps like MSQRD.
8. ShivaHuang commented on May 30, 2017

   

   ShivaHuang

   on May 30, 2017

   Last edited by ShivaHuang

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   Hi @SoundandStuff, what kind of flash do you mean? Some white frames at the beginning and the end? Or black frames?

   I found the similar issue which occurred on the old GPUImage, and fortunately @zmzhuai found a solution. (BradLarson/GPUImage#2410)

   I've fix the issue based on @zmzhuai's work and created a PR (#161), maybe you can give it a try?
9. ivanvelkov commented on Aug 31, 2017

   

   ivanvelkov

   on Aug 31, 2017

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   We experienced the same issue when we had the camera working but not recording. Once we wanted to record we:

   • created an instance of MovieOutput
   • set camera.audioEncodingTarget = movieOutput
   • started recording via movie.start()
     However the initialization processes caused a quick flash, we believe was caused by the setter of the audioEncodingTarget and specifically
   • removeAudioInputsAndOutputs()
   • addAudioInputsAndOutputs()
     So what we ended up doing is-
     camera.delegate = self;
     where self implements AudioEncodingTarget and inside the public func processAudioBuffer(_ sampleBuffer:CMSampleBuffer) method we invoke movieOutput.processAudioBuffer(sampleBuffer)
     That way the MovieOutput always receives the audio and video buffers and when the recording is started there is no initializations needed

   👍React with 👍2Reacted by Artak and WenjieHu
10. joshbernfeld commented on Nov 21, 2017

    

    joshbernfeld

    on Nov 21, 2017

    Last edited by joshbernfeld

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    The problem here is that the audio inputs and outputs are being recreated each time you start and stop a video. Going off the SimpleVideoRecorder example, the solution I found was to expose addAudioInputsAndOutputs() on the Camera, and call that function right after you setup your Camera.

    do {
        try self.camera?.addAudioInputsAndOutputs()
    } catch {
        print("Could not initialize audio inputs and outputs: \(error)")
    }
    

    Lastly, the most important thing is to not allow your Camera's audio inputs and outputs to be destroyed when you set self.camera.audioEncodingTarget = nil after finishing recording. You can prevent this from happening by commenting out self.removeAudioInputsAndOuputs() in the setter

    public var audioEncodingTarget:AudioEncodingTarget? {
        didSet {
            guard let audioEncodingTarget = audioEncodingTarget else {
                //This line below commented out
                //self.removeAudioInputsAndOutputs()
                return
            }
            do {
                try self.addAudioInputsAndOutputs()
                audioEncodingTarget.activateAudioTrack()
            } catch {
                fatalError("ERROR: Could not connect audio target with error: \(error)")
            }
        }
    }