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• OpenCV accept HTTP video streaming with different endpoints

  22 juin 2019, par nabroyan

  I am writing a server, which receives live video stream over HTTP and performs some operations for different endpoints.

  I am using OpenCV for that and my basic code looks somethings like this

  void f1()
  
  {
  
      cv::VideoCapture cap("http://localhost:8080/operation1");
  
      if (!cap.isOpened())
  
          return;
  
  
  
      for (;;)
  
      {
  
          cv::Mat frame;
  
          cap >> frame;
  
  
  
          // do something
  
      }
  
  }
  
  
  
  void f2()
  
  {
  
      cv::VideoCapture cap("http://localhost:8080/operation2");
  
      if (!cap.isOpened())
  
          return;
  
  
  
      for (;;)
  
      {
  
          cv::Mat frame;
  
          cap >> frame;
  
  
  
          // do something else
  
      }
  
  }
  
  
  
  void f3() {...}

  As you see each function listens to a different HTTP endpoint and does different operation. Each function runs in a separate thread.

  The problem is that for some reason OpenCV ignores the resource part in endpoint i.e. if ip:port is correct it will accept the stream no matter it is from operation1 or operation2.

  For testing purposes I use this command as a stream generator
  ffmpeg -i sample.mp4 -listen 1 -f matroska -c:v libx264 -preset fast -tune zerolatency  http://localhost:8080/operation1

  How can I make OpenCV to differentiate between HTTP endpoints ? What am I missing ? I have no any previous experience with OpenCV and photo/video stuff.

• How to convert bitmaps array to a video in Android ?

  12 juillet 2020, par Kamran Janjua

  I have a buffer which is filled with image bitmaps as they arrive (using a thread to continuously take pictures). I would then like to dump that bitmap buffer (I have a hashmap at the moment for matching the keys) into a .mp4 file.

  


  Here is the code to continuously capture the images using a handler.

  


  button.setOnClickListener {
 prepareUIForCapture()
 if(isRunning){
   handler.removeCallbacksAndMessages(null)
   Logd("Length of wide: " + MainActivity.wideBitmaps.size)
   Logd("Length of normal: " + MainActivity.normalBitmaps.size)
   // This is where the make video would be called => makeVideoFootage()
   restartActivity()
 }else{
    button.text = "Stop"
    handler.postDelayed(object : Runnable {
    override fun run(){
       twoLens.reset()
       twoLens.isTwoLensShot = true
       MainActivity.cameraParams.get(dualCamLogicalId).let {
                if (it?.isOpen == true) {
                Logd("In onClick. Taking Dual Cam Photo on logical camera: " + dualCamLogicalId)
                takePicture(this@MainActivity, it)
                Toast.makeText(applicationContext, "Captured", Toast.LENGTH_LONG).show()
                            }
                        }
                        handler.postDelayed(this, 1000)
                    }
                }, 1000)
            }
            isRunning = !isRunning
        }


  


  This takes picture every 1 second until the stop button is pressed. Here is the function that retrieves the images and saves them into a hashmap.

  


  val wideBuffer: ByteBuffer? = twoLens.wideImage!!.planes[0].buffer
val wideBytes = ByteArray(wideBuffer!!.remaining())
wideBuffer.get(wideBytes)

val normalBuffer: ByteBuffer? = twoLens.normalImage!!.planes[0].buffer
val normalBytes = ByteArray(normalBuffer!!.remaining())
normalBuffer.get(normalBytes)

val tempWideBitmap = BitmapFactory.decodeByteArray(wideBytes, 0, wideBytes.size, null)
val tempNormalBitmap = BitmapFactory.decodeByteArray(normalBytes, 0, normalBytes.size, null)
MainActivity.counter += 1
MainActivity.wideBitmaps.put(MainActivity.counter.toString(), tempWideBitmap)
MainActivity.normalBitmaps.put(MainActivity.counter.toString(), tempNormalBitmap)


  


  counter is used to match the frames and that is why I am using a hashmap instead of an array. I have complied the ffmpeg as follows.

  


  implementation 'com.writingminds:FFmpegAndroid:0.3.2'



  


  Is this the correct way ?
I would appreciate some starter code in makeVideoFootage().

  


  fun makeVideoFootage(){
// I would like to get the bitmaps from MainActivity.wideBitmaps and then dump them into a video wide.mp4.
}


  


  Any help regarding this would be appreciated.

  


  P.S. I have read the existing questions and their answers (running from the command line), but I do not know how to proceed.

  


• How to add video play duration ffmpeg ? [duplicate]

  2 août 2019, par Mostafa Daash

  This question already has an answer here :

  • Time stamped video to time stamped images
    
    1 answer
    

  i want to add video duration stamp in mp4 file

  like this photo
  https://i.ibb.co/m6cd63k/Untitled-1.jpg

  i use this code to output video file with watermark

  ffmpeg -i 22.mp4 -i logo50.png -filter_complex "overlay=x=40:10:y=20" -preset medium -crf 24 -codec:a aac -b:a 128k -codec:v libx264 -pix_fmt yuv420p 22.xxxx.mp4