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• Android Samsung Galaxy S2 / S3 device bitmap rendering to ImageView issue

  18 décembre 2014, par Steve

  I am stuck in a very strange Bitmap rendering issue with Samsung Android devices. Let me discuss in brief what I have done.

  I am taking frame from a video and rendering it in a ImageView using ffmpeg. Following code gives me a bitmap object in return from JNI callback.

      img_convert_ctx = sws_getContext(pCodecCtx->width,
  
              pCodecCtx->height, pCodecCtx->pix_fmt, target_width,
  
          target_height, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL,NULL);
  
  
  
      sws_scale(img_convert_ctx,(const uint8_t* const *) 
  
          pFrame->data,pFrame->linesize, 0, pCodecCtx->height,pFrameRGB->data, 
  
  pFrameRGB->linesize);

  Next, I’m just setting the Bitmap to ImageView. Now the issue is the Bitmap I get is rendering very well in maximum devices except Samsung S2/S3.

  A>Working well In :- Screen Shot 1

  1. Nexus 4
  2. HTC One / HTC One x
  3. LG Optimus
  4. Sony Experia
  5. Samsung Galaxy S Plus / Samsung Exhibit (Android 2.3)

  Issue With :-
  B>Samsung Galaxy S2 & S3 : The second screen shot.

  For Case B, A part of the video is rendering at the right side if you notice.

  I have tried saving the Bitmap I get from JNI as jpg in SD card and read that again to set the ImageView and it works. I Don’t understand what is going wrong with the raw Bitmap that I get from JNI callback, is it with Samsung S2 Hardware ? Please someone help me on this.

  

  

• Merge individual frame to video file using Opencv and FFmpeg

  16 août 2022, par Rohit

  I am trying to stack a individual frame to a video file using Opencv. I want to combine two different code together to make the individual frame.
Following code help me extract the individual frame

  


  while True:
ret, frame=cap.read()
mask = object_detector.apply(frame)
_, mask  = cv2.threshold(mask,254,255,cv2.THRESH_BINARY)       
contours,_ = cv2.findContours(mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
res = cv2.bitwise_and(frame,frame,mask=mask)
for cnt in contours:
    area = cv2.contourArea(cnt)
    if area>1000:   
        #print("Area of contour:", area)
        cv2.drawContours(frame, [cnt], -1, (0,255,0),2)
        cv2.imwrite("file%d.jpg"%count, frame)


  


  And I attach the frame together separately using following code using ffmpeg command

  


  ffmpeg -r 3 -i frame%03d.jpg -c:v libx264 -vf fps=25 -pix_fmt yuv420p video.mp4


  


  I tried storing the individual frame in array, but it didn't work. It doesn't show any error, but pc crash.

  


• Convert m4a to m4a with 3gp4 codec using ffmpeg, for compatibility with samsung audio recorder app [closed]

  17 août 2023, par Ash

  I need to convert my m4a audio files to m4a but will a 3gp4 codec (it seems samsung audio recording app only recognizes those with 3gp4 codec).

  


  How can i do that with ffmpeg or any other program ?

  


  I tried

  


  ffmpeg -i input.m4a -brand "3gp4" output.m4a


  


  This did change the major brand to 3gp4 but samsung recorder app still doesn't recognize the audio file.