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• FFmpegFrameGrabber and FFmpegFrameRecorder Audio Issue

  20 août 2015, par Sheheryar Chagani

  I am compress an existing camera recorded video using FFmpegframerecorder and ffmpegFrameGrabber.

  The issue is that its audio is not occurring after compression.

  Please note that I am using googlecode.javacv along with javacpp and armeabi in lib folder.

  Below is the code which I have used.

  public void compressVideo(String filePath)

      FrameGrabber grabber = new FFmpegFrameGrabber(filePath);
  
      grabber.start();
  
      fileoutput = filePath.replace("trimmed", "compressed");
  
      // recorder.setAudioCodec(grabber.get);
  
      FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(fileoutput, 480,
  
              480, grabber.getAudioChannels());
  
      recorder.setFrameRate(grabber.getFrameRate());
  
      recorder.setSampleRate(grabber.getSampleRate());
  
      recorder.setSampleFormat(grabber.getSampleFormat());
  
      recorder.setFormat(grabber.getFormat());
  
      // recorder.setPixelFormat(grabber.getPixelFormat());
  
  
  
      recorder.start();
  
      Frame frame;
  
      int count = 0;
  
      while ((frame = grabber.grabFrame()) != null) {
  
          if (frame.image != null) {
  
              publishProgress(count);
  
              count++;
  
              IplImage rotateImage = rotate(frame.image, 90);
  
              IplImage cropImage = resizeImage(rotateImage, 480, 480, true);
  
              frame.image = cropImage;
  
              recorder.record(frame);
  
              if (rotateImage != null)
  
                  opencv_core.cvReleaseImage(rotateImage);
  
              if (cropImage != null)
  
                  opencv_core.cvReleaseImage(cropImage);
  
          } else {
  
              recorder.record(frame);
  
          }
  
  
  
      }
  
      recorder.stop();
  
      grabber.stop();
  
      recorder.release();
  
      grabber.release();
  
  }
  
  
  
  IplImage resizeImage(IplImage origImg, int newWidth, int newHeight,
  
          boolean keepAspectRatio) {
  
  
  
      IplImage outImg;
  
      int origWidth = 0;
  
      int origHeight = 0;
  
      if (origImg != null) {
  
          origWidth = origImg.width();
  
          origHeight = origImg.height();
  
      }
  
      if (newWidth <= 0 || newHeight <= 0 || origImg == null
  
              || origWidth <= 0 || origHeight <= 0) {
  
          // cerr << "ERROR: Bad desired image size of " << newWidth
  
          // << "x" << newHeight << " in resizeImage().\n";
  
          return null;
  
      }
  
  
  
      if (keepAspectRatio) {
  
          // Resize the image without changing its aspect ratio,
  
          // by cropping off the edges and enlarging the middle section.
  
          CvRect r;
  
          // input aspect ratio
  
          float origAspect = (origWidth / (float) origHeight);
  
          // output aspect ratio
  
          float newAspect = (newWidth / (float) newHeight);
  
          // crop width to be origHeight * newAspect
  
          if (origAspect > newAspect) {
  
              int tw = (origHeight * newWidth) / newHeight;
  
              // System.out.println((origWidth - tw) / 2+" "+)
  
              r = opencv_core.cvRect((origWidth - tw) / 2, 0, tw, origHeight);
  
          } else { // crop height to be origWidth / newAspect
  
              int th = (origWidth * newHeight) / newWidth;
  
              r = opencv_core.cvRect(0, (origHeight - th) / 2, origWidth, th);
  
          }
  
          IplImage croppedImg = cropImage(origImg, r);
  
  
  
          // Call this function again, with the new aspect ratio image.
  
          // Will do a scaled image resize with the correct aspect ratio.
  
          outImg = resizeImage(croppedImg, newWidth, newHeight, false);
  
          opencv_core.cvReleaseImage(croppedImg);
  
  
  
      } else {
  
  
  
          // Scale the image to the new dimensions,
  
          // even if the aspect ratio will be changed.
  
          outImg = opencv_core.cvCreateImage(
  
                  opencv_core.cvSize(newWidth, newHeight), origImg.depth(),
  
                  origImg.nChannels());
  
          if (newWidth > origImg.width() && newHeight > origImg.height()) {
  
              // Make the image larger
  
              opencv_core.cvResetImageROI((IplImage) origImg);
  
              // CV_INTER_LINEAR: good at enlarging.
  
              // CV_INTER_CUBIC: good at enlarging.
  
              cvResize(origImg, outImg, CV_INTER_LINEAR);
  
          } else {
  
              // Make the image smaller
  
              opencv_core.cvResetImageROI((IplImage) origImg);
  
              // CV_INTER_AREA: good at shrinking (decimation) only.
  
              cvResize(origImg, outImg, CV_INTER_AREA);
  
          }
  
  
  
      }
  
      return outImg;
  
  }
  
  
  
  // Returns a new image that is a cropped version (rectangular cut-out)
  
  // of the original image.
  
  IplImage cropImage(IplImage img, CvRect region) {
  
      IplImage imageCropped;
  
      opencv_core.CvSize size = new CvSize();
  
  
  
      if (img.width() <= 0 || img.height() <= 0 || region.width() <= 0
  
              || region.height() <= 0) {
  
          // cerr << "ERROR in cropImage(): invalid dimensions." << endl;
  
          return null;
  
      }
  
  
  
      if (img.depth() != opencv_core.IPL_DEPTH_8U) {
  
          // cerr << "ERROR in cropImage(): image depth is not 8." << endl;
  
          return null;
  
      }
  
  
  
      // Set the desired region of interest.
  
      opencv_core.cvSetImageROI((IplImage) img, region);
  
      // Copy region of interest into a new iplImage and return it.
  
      size.width(region.width());
  
      size.height(region.height());
  
      imageCropped = opencv_core.cvCreateImage(size,
  
              opencv_core.IPL_DEPTH_8U, img.nChannels());
  
      opencv_core.cvCopy(img, imageCropped); // Copy just the region.
  
  
  
      return imageCropped;
  
  }
  
  
  
  public IplImage rotate(IplImage image, double angle) {
  
      IplImage copy = opencv_core.cvCloneImage(image);
  
  
  
      IplImage rotatedImage = opencv_core.cvCreateImage(
  
              opencv_core.cvGetSize(copy), copy.depth(), copy.nChannels());
  
      CvMat mapMatrix = opencv_core.cvCreateMat(2, 3, opencv_core.CV_32FC1);
  
  
  
      // Define Mid Point
  
      CvPoint2D32f centerPoint = new CvPoint2D32f();
  
      centerPoint.x(copy.width() / 2);
  
      centerPoint.y(copy.height() / 2);
  
  
  
      // Get Rotational Matrix
  
      opencv_imgproc.cv2DRotationMatrix(centerPoint, angle, 1.0, mapMatrix);
  
  
  
      // Rotate the Image
  
      opencv_imgproc.cvWarpAffine(copy, rotatedImage, mapMatrix,
  
              opencv_imgproc.CV_INTER_CUBIC
  
                      + opencv_imgproc.CV_WARP_FILL_OUTLIERS,
  
              opencv_core.cvScalarAll(170));
  
      opencv_core.cvReleaseImage(copy);
  
      opencv_core.cvReleaseMat(mapMatrix);
  
      return rotatedImage;
  
  }

  I am rotating the video frame and then resizing the frame image.

  The code was working fine 3 days ago but not suddenly it started messing up.

• Does anyone know any filters for better low quality video ?

  7 septembre 2022, par kasten

  So maybe my question can be closed, but anyway I'm researching and looking for a tool that can do the following with video files :

  


  Here's an example of what I want :

  


  When you put a low quality video on your TV and look into a mirror that reflects that image, it appears to be sharper, acting as a filter to improve the video.

  


  I don't know if anyone has thought of this fact or if there is a software that does something similar. I know low quality video can't get any better, but why is there an improvement when looking in the mirror ?

  


  I appreciate if anyone can comment, as I'm not a professional in video.

  


• Real time livestreaming - RPI FFmpeg and H5 Player

  29 avril 2022, par Victor

  I work at a telehealth company and we are using connected medical devices in order to provide the doctor with real time information from these equipements, the equipements are used by a trained health Professional.

  


  Those devices work with video and audio. Right now, we are using them with peerjs (so peer to peer connection) but we are trying to move away from that and have a RPI with his only job to stream data (so streaming audio and video).

  


  Because the equipements are supposed to be used with instructions from a doctor we need the doctor to receive the data in real time.

  


  But we also need the trained health professional to see what he is doing (so we need a local feed from the equipement)

  


  How do we capture audio and video

  


  We are using ffmpeg with a go client that is in charge of managing the ffmpeg clients and stream them to a SRS server.
This works but we are having a 2-3 sec delay when streaming the data. (rtmp from ffmpeg and flv on the front end)

  


  ffmpeg settings :

  


  ("ffmpeg", "-f", "v4l2", `-i`, "*/video0", "-f", "flv", "-vcodec", "libx264", "-x264opts", "keyint=15", "-preset", "ultrafast", "-tune", "zerolatency", "-fflags", "nobuffer", "-b:a", "160k", "-threads", "0", "-g", "0", "rtmp://srs-url")


  


  My questions

  


  

  • Is there a way for this set up to achieve low latency (<1 sec) (for the nurse and for the doctor) ?

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  • Is the way I want to achieve this good ? Is there a batter way ?

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  Flow schema

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  Data exchange and use case flow :

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  Note : The nurse and doctor use HTTP-FLV to play the live stream, for low latency.

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