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• Displaying 450 image files from SDCard at 30fps on android

  11 décembre 2013, par nikhilkerala

  I am trying to develop an app that takes a 15 seconds of video, allows the user to apply different filters, shows the preview of the effect, then allows to save the processed video to sdcard. I use ffmpeg to split the video into JPEG frames, apply the desired filter using GPUImage to all the frames, then use ffmpeg to encode the frames back to a video. Everything works fine except the part where user selects the filter. When user selects a filter, the app is supposed to display the preview of the video with the filter applied. Though 450 frames get the filter applied fairly quick, displaying the images sequentially at 30 fps (to make the user feel the video is being played) is performing poorly. I tried different approaches but the maximum frame rate I could attain even on the fastest devices is 10 to 12 fps.

  The AnimationDrawable technique doesn't work in this case because it requires the entire images to be buffered into memory which in this case is huge. App crashes.

  The below code is the best performing one so far (10 to 12 fps).

  package com.example.animseqvideo;
  
  import ......
  
  
  
  public class MainActivity extends Activity {
  
      Handler handler;
  
      Runnable runnable;
  
      final int interval = 33; // 30.30 FPS
  
      ImageView myImage;
  
      int i=0;
  
  
  
      @Override
  
      protected void onCreate(Bundle savedInstanceState) {
  
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.activity_main);
  
  
  
          myImage = (ImageView) findViewById(R.id.imageView1);
  
  
  
          handler = new Handler();
  
          runnable = new Runnable(){
  
              public void run() {
  
  
  
                  i++;  if(i>450)i=1;
  
  
  
                  File imgFile = new  File(Environment.getExternalStorageDirectory().getPath() + "/com.example.animseqvideo/image"+ String.format("%03d", i)   +".jpg");
  
                  if(imgFile.exists()){
  
                      Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
  
                      myImage.setImageBitmap(myBitmap);
  
                  }
  
  //SOLUTION EDIT - MOVE THE BELOW LINE OF CODE AS THE FIRST LINE OF run() AND FPS=30 !!!
  
  
  
                  handler.postDelayed(runnable, interval);
  
              }
  
          };
  
          handler.postAtTime(runnable, System.currentTimeMillis()+interval);
  
          handler.postDelayed(runnable, interval);
  
      }
  
  }

  I understand that the process of getting an image from SDCard, decoding it, then displaying it onto the screen involves the performance of the SDCard reading, the CPUs performance and graphics performance of the device. But I am wondering if there is a way I could save a few milliseconds in each iteration. Any suggestion would be of great help at this point.

• how to remove noise from buffer

  7 décembre 2013, par Ari

  I am integrating an media player kind of app

  I have converted the audio file format into buffer, and I have applied bass,treble filters with high gain then i got noise.How to minimise or eliminate that noise from audio in ffmpeg or is there any another way such that i can remove noise using java code by doing changes in byte i.e(audio buffer)

  here is my code :

      void playSound(byte[] buf, final int size) 
  
   {     
  
       trackStereo.write(buf, 0,size);
  
       trackStereo.play();
  
  
  
      buf = null;
  
   }
  
  bufSizeStereo =  AudioTrack.getMinBufferSize(44100,
  
    AudioFormat.CHANNEL_OUT_STEREO,
  
   AudioFormat.ENCODING_PCM_16BIT);
  
      trackStereo = new AudioTrack(AudioManager.STREAM_MUSIC, 44100,
  
  AudioFormat.CHANNEL_OUT_STEREO,
  
  AudioFormat.ENCODING_PCM_16BIT, bufSizeStereo,
  
  AudioTrack.MODE_STREAM);
  
      bytes = new byte[bufSizeStereo];

  how remove noise from byte before playing the audio

  Thanks

• New Piwik 2.0 public beta for testers

  16 octobre 2013, par matt

  Dear Piwik community,

  We are excited to announce the release of the first public beta version of Piwik 2.0.

  This is software still in development and we really don’t recommend that you run it on a production site — set up a test database just to play with the new version.

  Piwik 2.0 is a major update from Piwik 1.12 and is the result of 5 months of work on the platform !

  What’s changed ?

  We focused on upgrading Piwik source code quality and maintainability : upgraded to PHP 5.3 using namespaces, changed templating library to Twig, started using composer, using Less as well as css, improved QA tests, introduced new Screenshots tests, refactored translations to nice JSON format, refactored LOTS of code, added documentation….

  There also performance improvements, in particular the “All Websites Dashboard” is now usable with 20,000+ websites !

  Several bugs were fixed and we added some very-special-and-exciting new features.

  See the list of closed tickets in Piwik 2.0, or learn more about our recent developments in the Development update blog post.

  Piwik 2 is the open platform for your analytics data !

  How to update to Piwik 2.0 beta ?

  1. You can tell Piwik to use the latest beta from within the user interface. See this FAQ : [piwik.org]
  2. or alternatively you may download the latest beta from the build server, upload these files on top of your existing piwik files, and visit Piwik to upgrade.

  Beta cycle
  The more you test the beta, the more stable our release candidates and our final release will be. If you think you’ve found a bug, you can post it in this forum post. Or, if you’re comfortable writing a reproducible bug report, file one. The stable Piwik 2.0 release is planned for mid-November !

  Happy testing,

  PS : if you are interested in professional support for Piwik, or custom feature development, contact the Piwik experts.