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• How to ensure plt.savefig saves multiple images instead of one ?

  18 mars 2018, par Natalie

  I’m trying to save images after for each iteration to show how my neural network is learning.

  for iterations in range(1,1000):
  
      model.fit(x_train, 
  
                y_train, 
  
                batch_size=20, 
  
                epochs=1, 
  
                verbose=2)
  
  
  
  predictions = model.predict(X)
  
  plt.plot(X,predictions,'o')
  
  plt.plot(r, morse(r,De,Re,alpha))
  
  plt.xlabel(r'$r$') # internuclear separation distance
  
  plt.ylabel(r'$V(r)$') # morse potential energy
  
  plt.savefig('myfig'+str(iterations))
  
  plt.clf()

  Originally, I was able to save every image, however, it now only saves the last iteration image only. I wondered how I might be able to solve this issue ?

  Also, related the first question : using the images I’m saving, I’m trying to merge all the images together into a quick movie to show the training process. I’ve been using ffmpeg (see image below for syntax error), but I keep getting syntax errors. Could anyone guide me through what I might be doing wrong ? ffmpeg syntax error I’m getting

  Thanks in advance for helping me out - completely new to machine learning but using it for a university project, so apologies for my lack of understanding/mistakes !!

• aacenc_tns : tune and reduce artifacts

  6 décembre 2015, par Rostislav Pehlivanov

  aacenc_tns : tune and reduce artifacts
  There are a couple of major changes here :
  1. Start using TNS coefficient compression.
  
  2. Start using 3 bits per coefficient maximum for short windows.
  
  The bits we save from these 2 changes seem to make a nice impact on the
  
  rest of the file/windows.
  3. Remove special case gain checking for short windows.
  
  4. Modify the coefficient loop to support up to 3 windows.
  
  The additional restrictions on TNS were something that was no in the
  
  specifications and furthermore restricting TNS to only low energy short
  
  windows was done to compensate for bugs elsewhere in the code.
  Overall, the improvements here reduce crackling artifacts heard in very
  
  noisy tracks.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/aacenc_tns.c

• ffmpeg extracting frames from video

  22 novembre 2017, par TheOtherguyz4kj

  I am using Writingminds FFmpeg to use FFmpeg with Android. I am currently trying to extract frames from a video.

  I would like to extract 8 frames from the video evenly distributed throughout the video. I found this tutorial here is my implementation of it.

  MediaMetadataRetriever retriever = new MediaMetadataRetriever();
  
      retriever.setDataSource(videoCroppedFile.getAbsolutePath());
  
      String time = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
  
      Long videoLength = Long.parseLong(time);
  
  
  
  
  
  final String cmd[] = {
  
  
  
              "-i",
  
              videoCroppedFile.getAbsolutePath(),
  
              "-f",
  
              "image2",
  
              "-ss",
  
              String.valueOf(videoLength.intValue() / ((8 + 1) * 10)),
  
              "-r",
  
              String.valueOf((8 + 1) / videoLength.intValue()),
  
              mediaStorageDir.getAbsolutePath() + "/%d.jpg"
  
      };

  However, when i go to the folder where the frames should be saved there isn’t anything there. Also there are no error messages.

  I feel like its a way this library takes the String parameters. I’ve been stuck on this for sometime I have tried lots of different versions of the cmd. I was hoping someone could help.

  Here is my output from ffmpeg :

  1-22 19:33:14.904 30981-30981/com.firebase.android D/videoFrames:  failure reason ffmpeg version n3.0.1 Copyright (c) 2000-2016 the FFmpeg developers
  
           built with gcc 4.8 (GCC)
  
           configuration: --target-os=linux --cross-prefix=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/bin/arm-linux-androideabi- --arch=arm --cpu=cortex-a8 --enable-runtime-cpudetect --sysroot=/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/sysroot --enable-pic --enable-libx264 --enable-libass --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-fontconfig --enable-pthreads --disable-debug --disable-ffserver --enable-version3 --enable-hardcoded-tables --disable-ffplay --disable-ffprobe --enable-gpl --enable-yasm --disable-doc --disable-shared --enable-static --pkg-config=/home/vagrant/SourceCode/ffmpeg-android/ffmpeg-pkg-config --prefix=/home/vagrant/SourceCode/ffmpeg-android/build/armeabi-v7a --extra-cflags='-I/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/include -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fno-strict-overflow -fstack-protector-all' --extra-ldflags='-L/home/vagrant/SourceCode/ffmpeg-android/toolchain-android/lib -Wl,-z,relro -Wl,-z,now -pie' --extra-libs='-lpng -lexpat -lm' --extra-cxxflags=
  
           libavutil      55. 17.103 / 55. 17.103
  
           libavcodec     57. 24.102 / 57. 24.102
  
           libavformat    57. 25.100 / 57. 25.100
  
           libavdevice    57.  0.101 / 57.  0.101
  
           libavfilter     6. 31.100 /  6. 31.100
  
           libswscale      4.  0.100 /  4.  0.100
  
           libswresample   2.  0.101 /  2.  0.101
  
           libpostproc    54.  0.100 / 54.  0.100
  
         Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/data/user/0/com.firebase.android/cache/videovgntp6q5ar4dglkaflaoobfpcv945824159.mp4':
  
           Metadata:
  
             major_brand     : isom
  
             minor_version   : 512
  
             compatible_brands: isomiso2avc1mp41
  
             encoder         : Lavf57.25.100
  
           Duration: 00:00:08.28, start: 0.000000, bitrate: 391 kb/s
  
             Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 720x764 [SAR 1:1 DAR 180:191], 132 kb/s, 16.67 fps, 16.67 tbr, 12800 tbn, 33.33 tbc (default)
  
             Metadata:
  
               handler_name    : VideoHandler
  
             Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 256 kb/s (default)
  
             Metadata:
  
               handler_name    : SoundHandler
  
         Invalid framerate value: 0

  Update 2

  Here is my Android code :

        try {
  
          ffmpeg.loadBinary(new LoadBinaryResponseHandler() {
  
  
  
              @Override
  
              public void onStart() {
  
                  Log.d("videoFrames", "starting to load binary");
  
              }
  
  
  
              @Override
  
              public void onFailure() {
  
                  Log.d("videoFrames", "failed to load binary");
  
              }
  
  
  
              @Override
  
              public void onSuccess() {
  
                  Log.d("videoFrames", "loaded binary");
  
                  try {
  
                      ffmpeg.execute(cmd, new ExecuteBinaryResponseHandler() {
  
  
  
                          @Override
  
                          public void onStart() {
  
                              Log.d("videoFrames", " starting to get frames from video");
  
                              if (mediaStorageDir.isDirectory() && mediaStorageDir.list().length > 0) {
  
                                  String[] children = mediaStorageDir.list();
  
                                  for (int i = 0; i < children.length; i++) {
  
                                      new File(mediaStorageDir, children[i]).delete();
  
                                  }
  
                              }
  
                          }
  
  
  
                          @Override
  
                          public void onProgress(String message) {
  
                              Log.d("videoFrames", " progress getting frames from video");
  
                          }
  
  
  
                          @Override
  
                          public void onFailure(String message) {
  
                              Log.d("videoFrames", " failed to get frames from video");
  
                              Log.d("videoFrames", " failure reason " + message);
  
                              Log.d("videoFrames", " ----------------------------------------------- ");
  
                          }
  
  
  
                          @Override
  
                          public void onSuccess(String message) {
  
                              Log.d("videoFrames", " success getting frames from video");
  
                          }
  
  
  
                          @Override
  
                          public void onFinish() {
  
                              Log.d("videoFrames", " finished getting frames from video");
  
                          }
  
                      });
  
                  } catch (FFmpegCommandAlreadyRunningException e) {
  
                      Log.d("videoFrames", " command already running in fmpeg");
  
                      e.printStackTrace();
  
                  }
  
              }
  
  
  
              @Override
  
              public void onFinish() {}
  
          });
  
      } catch (FFmpegNotSupportedException e) {
  
          // Handle if FFmpeg is not supported by device
  
      }

  Update 3

  I fixed my code by doing :

   final String cmd[] = {
  
  
  
              "-i",
  
              videoCroppedFile.getAbsolutePath(),
  
              "-f",
  
              "image2",
  
              "-ss",
  
              String.valueOf(videoLength.floatValue() / (8.0  * 10.0)),
  
              "-r",
  
              String.valueOf(8.0 / videoLength.floatValue()),
  
              mediaStorageDir.getAbsolutePath() + "/%d.jpg"
  
      };