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• Video width is different in different devices

  8 novembre 2017, par David

  I have a special video when i want to get this video’s width code returns different value for Samsung galaxy s6 and Samsung note 3. I tested many different codes and libraries, but result is the same.
  in Samsung galaxy s6 : 640x480
  in Samsung note 3 : 853x480
  when I open this video with Gspot program it shows :

  Recommended Display Size : 853x480

  and this is the same value is returned by our IOS app tested in Iphone 7. aspect radio is not the same and this is big problem.

  here is some of codes I tested :

  (1)

      MediaMetadataRetriever metaRetriever = new MediaMetadataRetriever();
  
      metaRetriever.setDataSource(path);
  
      Bitmap bmp = metaRetriever.getFrameAtTime(-1);
  
  
  
      int height = bmp.getHeight();
  
      int width = bmp.getWidth();

  (2)

      MediaPlayer myMediaPlayer= MediaPlayer.create(ApplicationLoader.applicationContext, 
  
                                       Uri.fromFile(new File(path)));
  
  
  
      width = myMediaPlayer.getVideoWidth();
  
      height = myMediaPlayer.getVideoHeight();

  (3)

   MediaMetadataRetriever metaRetriever = new MediaMetadataRetriever();
  
          metaRetriever.setDataSource(path);
  
   String heights = metaRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT);
  
          String widths = metaRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH);
  
      int height = Integer.valueOf(heights);
  
          int width = Integer.valueOf(widths);

  (4)

    MediaPlayer myMediaPlayer= MediaPlayer.create(ApplicationLoader.applicationContext, Uri.fromFile(new File(path)));
  
              myMediaPlayer.setOnVideoSizeChangedListener((mp, width, height) -> {
  
          int videoWidth = width;
  
          int videoHeight = height;
  
      );
  
              myMediaPlayer.setDataSource(path);
  
              myMediaPlayer.prepare();

  FFmpegMediaMetadataRetriever, FFmpeg Java, ExoPlayer and some other libraries returns the same result.

• HEVC video cutting issues using FFmpeg

  4 novembre 2017, par Dmitry Katkevich

  I need to cut videos using FFmpeg and I cannot transcode original videos (because of the performance reason). And I ran into a problem with HEVC videos from IPhone : there are glithes in the beginning of the cutted video.

  Here is how we converted videos before issue :

  ffmpeg.exe -i original.MOV -c:v copy -c:a aac -ss 4 -y good.mp4

  But for HEVC video there are glitches for 1 second in the beginning of the cutted video :

  

  Then I’ve tried to put seek option before input video :

  ffmpeg.exe -ss 4 -i original.MOV -c:v copy -c:a aac -y good.mp4

  The result seems good :

  

  After some googling it turns out that -ss option before input is faster but less accurate whereas -ss option after input and before output is slower but more accurate.

  So my questions are :

  • Why -ss option behaves differently then it is put before/after input ?

  • Is there a way to avoid glitches using output seek ffmpeg option ?

  • What does ’more/less accurate’ mean ? Does it mean that the seek may be too big or to little (bigger/less than we specified) ? How big may be this difference ?

• FFmpeg HLS Live Stream Stuck with iOS 11

  1er novembre 2017, par Lamorun

  I’ve exp with FFmpeg but i recent problem with iOS 11 (Recent release for Apple)

  I used FFmpeg for stream HLS Live Stream for only iPhone and iPad in closed app for online courses. My problem is the next :

  I used this code for HLS Live Stream :

  ffmpeg -i "Input" -preset fast -c:v libx264 -c:a aac -ac 1 -strict -2 -crf 18 -profile:v baseline -maxrate 1000k -bufsize 1835k -pix_fmt yuv420p -b:a 64k -flags -global_header -hls_time 20 -hls_list_size 6 -hls_wrap 10 -start_number 1 /m3u8/test.m3u8

  This work perfect in iOS 8, 9 and 10 devices. But with new version iOS 11, video is stuck after about 30 to 40 seconds, as seen in the image :

  ios11stuck

  I have searched for hours and hours. I have done many tests, but I can not get it out, since it works perfectly with iOS 8,9 and 10 (test in somes devices, even working perfectly on a device with iOS 10, update to iOS 11, and stop working immediately, downgrade to iOS 10 and work again)

  I hope someone can help me out, thank you and greetings to all