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• Anomalie #4430 : image_reduire gère mal les arrondis

  4 février 2020, par jluc -

  L’image initiale fait 640 × 427 pixels.
  |image_proportions1,1,focus produit correctement une image de 427x427. Il est donc probable qu’on reproduit le pb directement à partir d’une image de 427x427

  En tout cas le résultat final fait réellement 200x201.

• ffmpeg Get time of frames from trimmed video

  17 novembre 2017, par TheOtherguyz4kj

  I am using FFmpeg in my application to extract frames from a video, the frames will be added to a trim video view where you get an illustration as to what is happening in the video at a specific time within the video. So each frame needs to represent some time within the video.

  I dont quite understand how FFmpeg is producing the frames. Here is my code :

  "-i",
  
  videoCroppedFile.getAbsolutePath(),
  
  "-vf",
  
  "fps=1/" + frameSeperation,
  
  mediaStorageDir.getAbsolutePath() +
  
  "/%d.jpg"

  My app allows you to record a video at a max length of 20s. The number of frames extracted from the video depnds on how long the captured video is. frameSeperation is calculated doing the below code.

  String time = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
  
      long videoLength = Long.parseLong(time) / 1000;
  
      double frameSeperationDouble = (double) videoLength;
  
      // Divide by 11 because there is a maximum of 11 frames on trim video view
  
      frameSeperationDouble /= 11;
  
      frameSeperationDouble = Math.ceil(frameSeperationDouble);
  
      int frameSeperation = (int) frameSeperationDouble;

  Maybe the above logic is very bad, if there is a better way please can somebody tell me.

  Anyway I run the code and below are a few test cases :

  • A video captured with a length of 6 seconds has 7 frames.
  • A video captured with a length of 2 seconds has 3 frames.
  • A video captured with a length of 10 seconds has 12 frames.
  • A video captured with a length of 15 seconds has 9 frames.
  • A video captured with a length of 20 seconds has 11 frames.

  There is no consistency, and I find it hard to put timestamps against each frame because of this. I feel like my logic is wrong or im not understanding. Any help is much appreciated

  Update 1

  So I did what you said in comments :

   final FFmpeg ffmpeg = FFmpeg.getInstance(mContext);
  
          final File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
  
                  + "/Android/data/"
  
                  + mContext.getPackageName()
  
                  + "/vFrames");
  
  
  
      if (!mediaStorageDir.exists()){
  
          mediaStorageDir.mkdirs();
  
      }
  
  
  
      MediaMetadataRetriever retriever = new MediaMetadataRetriever();
  
      retriever.setDataSource(mContext, Uri.fromFile(videoCroppedFile));
  
      String time = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
  
      long videoLength = Long.parseLong(time) / 1000;
  
      double frameSeperationDouble = (double) videoLength / 8;
  
  
  
      retriever.release();
  
  
  
      final String cmd[] = {
  
  
  
              "-i",
  
              videoCroppedFile.getAbsolutePath(),
  
              "-vf",
  
              "fps=1/" + frameSeperationDouble,
  
              "-vframes," + 8,
  
              mediaStorageDir.getAbsolutePath() +
  
              "/%d.jpg"
  
      };

  I also tried "-vframes=" + 8 at the same point where I put vFrames in cmd. It doesnt seem to work at all now no frames are being extracted from the video

• MediaMetadataRetriever setDataSource failed : status = 0xFFFFFFED

  10 octobre 2019, par darja

  I need to fetch frames from video located in the web. That’s how I do this :

  class PlayerWrapper {
  
      private static final MediaMetadataRetriever mMediaMetadataRetriever = new MediaMetadataRetriever();
  
  
  
      …
  
  
  
      public void initPlayback(final Context context, final VideoSurfaceView videoSurface, final String url) {
  
          new Thread(new Runnable() {
  
              @Override
  
              public void run() {
  
                  …
  
  
  
                  try {
  
                      mMediaMetadataRetriever.setDataSource(url, new HashMap());
  
                  } catch (Exception e) {
  
                      DPLog(e);
  
                  }
  
  
  
              }
  
          }).start();
  
      }
  
  
  
      public Bitmap getFrameAt(int positionMillis) {
  
          if (mMediaMetadataRetriever != null) {
  
              DPLog.d("Creating frame for position [%s]", positionMillis);
  
              try {
  
                  return mMediaMetadataRetriever.getFrameAtTime(positionMillis * 1000);
  
              } catch (Exception e) {
  
                  …
  
                  return null;
  
              }
  
          } else {
  
              return null;
  
          }
  
      }
  
  }

  This works fine on several devices with Android 4.4, 5 and 6. But on one device with Android 4.1.2 setDataSource function fails with following stack trace :

  java.lang.RuntimeException: setDataSource failed: status = 0xFFFFFFED
  
         at android.media.MediaMetadataRetriever._setDataSource(MediaMetadataRetriever.java)
  
         at android.media.MediaMetadataRetriever.setDataSource(MediaMetadataRetriever.java:99)
  
         at co.unreel.videoapp.playback.UnreelPlayer$3.run(UnreelPlayer.java:138)
  
         at java.lang.Thread.run(Thread.java:856)

  Also tried this code on emulator, got almost the same but with status 0x80000000

  Url is got from YouTube API, looks like this :

  https://r2---sn-n3toxu-axqe.googlevideo.com/videoplayback?gcr=ru&sver=3&mm=31&mn=sn-n3toxu-axqe&key=yt6&signature=D1CE7B8615F3D96A58A9D2679057D676E7777E05.5A318AD8C5F48FCED2D1A9149348CD269F466FA9&mt=1456173450&pl=24&mv=m&ms=au&lmt=1455616987173757&itag=22&requiressl=yes&ip=188.242.217.203&source=youtube&dur=848.248&id=o-ABIn_CbRwqIO6qpvlaWe_ekyTZPLVd0w_eM80awd6uRQ&fexp=9408087%2C9416126%2C9419451%2C9420452%2C9421340%2C9422596%2C9423661%2C9423662%2C9425078%2C9425963%2C9427767%2C9427801%2C9428013%2C9428432%2C9428660%2C9429602&mime=video%2Fmp4&upn=P5qxGGbPoc0&sparams=dur%2Cgcr%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Cratebypass%2Crequiressl%2Csource%2Cupn%2Cexpire&expire=1456195127&initcwndbps=3140000&ratebypass=yes&ipbits=0

  Permissions :

  Why this can happen and what to do ?

  I also tried to use FFmpegMediaMetadataRetriever with the same logic, but it doesn’t work at all, setDataSource causes exceptions with status 0xFFFFFFFF on all devices. As I found on SO, that means that url is invalid, but it is ok and played by MediaPlayer without any issues. Also I found that ffmpeg has issues with urls longer than 1024, but that’s not my case too.

  May be there are another way to get frames from video ?