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• Rotation on Video frame image makes video quality low and becomes green ffmpeg opencv

  21 novembre 2013, par bindal

  I am working on one application in which i have to record video on touch which includes pause recording so , i am using FFmpegFrameRecorder for that

  But when i am recording video with rear camera then in onpreviewframe
  i am getting yuvIplImage in portrait mode that is correct but when i
  am recording with front camera in portrait mode then in onPreviewframe
  i am getting image upside down , so my half, so from that result my
  half video is showing in correct portrait mode and remaining half
  video id showing upside down, so i am applying rotation on yuvIplImage
  when recording from front camera

  Here is my onPreviewFrame Method

   @Override
  
              public void onPreviewFrame(byte[] data, Camera camera) {
  
  
  
                  long frameTimeStamp = 0L;
  
                  if (mAudioTimestamp == 0L && firstTime > 0L)
  
                      frameTimeStamp = 1000L * (System.currentTimeMillis() - firstTime);
  
                  else if (mLastAudioTimestamp == mAudioTimestamp)
  
                      frameTimeStamp = mAudioTimestamp + frameTime;
  
                  else {
  
                      long l2 = (System.nanoTime() - mAudioTimeRecorded) / 1000L;
  
                      frameTimeStamp = l2 + mAudioTimestamp;
  
                      mLastAudioTimestamp = mAudioTimestamp;
  
                  }
  
                  synchronized (mVideoRecordLock) {
  
                      if (recording && rec && lastSavedframe != null
  
                              && lastSavedframe.getFrameBytesData() != null
  
                              && yuvIplImage != null) {
  
                          mVideoTimestamp += frameTime;
  
                          if (lastSavedframe.getTimeStamp() > mVideoTimestamp)
  
                              mVideoTimestamp = lastSavedframe.getTimeStamp();
  
                          try {
  
                              yuvIplImage.getByteBuffer().put(
  
                                      lastSavedframe.getFrameBytesData());
  
                              videoRecorder.setTimestamp(lastSavedframe
  
                                      .getTimeStamp());
  
  
  
                              // if (defaultCameraId == 1) {
  
                              // CvSize size = new CvSize(yuvIplImage.height(),
  
                              // yuvIplImage.width());
  
                              // IplImage yuvIplImage2 = opencv_core.cvCreateImage(
  
                              // size, yuvIplImage.depth(),
  
                              // yuvIplImage.nChannels());
  
                              //
  
                              // videoRecorder.record(yuvIplImage2);
  
                              // } else {
  
  
  
                              // }
  
  
  
  
  
  
  
                              if (defaultCameraId == 1) {
  
                                  yuvIplImage = rotate(yuvIplImage, 270);
  
  
  
                                  videoRecorder.record(yuvIplImage);
  
                              }else
  
                              {
  
                                  videoRecorder.record(yuvIplImage);
  
                              }
  
                              // else
  
  
  
                              // opencv_core.cvTranspose(yuvIplImage, yuvIplImage);
  
                          } catch (com.googlecode.javacv.FrameRecorder.Exception e) {
  
                              e.printStackTrace();
  
                          }
  
                      }
  
                      lastSavedframe = new SavedFrames(data, frameTimeStamp);
  
                  }
  
              }
  
          } 

  Here is rotation function

  public static 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);
  
      // opencv_core.cvReleaseImage(copy);
  
  
  
      // 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;
  
  }

  But Final output of video makes half of the video green

  Thanks in advance

• FFMPEG : burn SRT files to a transparent video file ?

  19 septembre 2017, par Taapo

  I need to create several versions of srt/ssa subtitles for another editor. To minimize the problems that can rise (encoding, etc) I want to provide a separate AVI file that can be overlayed onto another file.

  So I would like to use FFMPEG to burn an "empty" (transparent) video file which has the length of the subtitle file, and with the subtitles burnt in. How would this be done in FFMPEG ?

  Before someone says this is a bad idea (which someone already did), there are use cases where this technique would be helpful. I’m fully aware that this would create big files, but most real-life editors don’t care about size - but about solutions. Judging from other posts (on other forums) there seem to be a need for others as well. And since a professional subtitler like Lemony Subtitler is offering the option, I suppose this is not really a bad idea.

• http: Add the trailing endlines if they are missing

  23 juillet 2015, par Luca Barbato

  http: Add the trailing endlines if they are missing
  Makes slightly easier the life of those want to use the option
  
  from the command line
  

  • [DH] libavformat/http.c