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  • Tap to record like in vine using javacv

    8 décembre 2015, par human123

    I am trying to implement a tap to record feature like in vine. A sample for handling recording (not touch to record) provided in javacv is https://github.com/bytedeco/javacv/blob/master/samples/RecordActivity.java. I am trying to modify it so that in onPreviewFrame method frames are added to buffer only when user has his finger placed on screen. These frames are then tried to be combined into final video in stopRecording method.

    The issue is that if I set the timestamp as given in below code snippet (in stopRecording method)

    if (t > recorder.getTimestamp())
    {
       recorder.setTimestamp(t);
    }

    the behavior is as below

    Case 1

    If I tap on screen to record for 2 seconds and take the finger away from screen for 3 seconds and then again place finger back on screen to record for another 4 seconds the resulting video is like,

    For 1st 2 seconds video has recorded content. For next 3 seconds (time when finger is put away from screen). video just shows the last frame recorded when finger was placed on screen last. Then the video has recorded video content for next 4 seconds. So there seems to be an issue in handling video recording when finger is removed from screen.

    Case 2

    Next I removed the code setting time stamp to recorder(the code snippet given above) in stopRecording method.

    Now the resulting video (for the same steps tried in case 1) does not contain the middle 3 seconds(which is what is required) when finger was taken away from screen. But video is playing at a faster rate. So it seems that we need to set time stamp so that video plays at normal rate.

    Full code of my activity is given below. (Please note that video recording is mainly handled from onPreviewFrame and stopRecording methods)

    public class TouchToRecordActivity extends Activity implements OnClickListener, View.OnTouchListener {

    private final static String CLASS_LABEL = "TouchToRecordActivity";
    private final static String LOG_TAG = CLASS_LABEL;

    private String ffmpeg_link = "/mnt/sdcard/stream.mp4";

    long startTime = 0;
    boolean recording = false;
    boolean rec = false;

    private FFmpegFrameRecorder recorder;

    private boolean isPreviewOn = false;

    private int sampleAudioRateInHz = 44100;
    private int imageWidth = 640;
    private int imageHeight = 480;
    private int destWidth = 480;
    private int frameRate = 30;

    /* audio data getting thread */
    private AudioRecord audioRecord;
    private AudioRecordRunnable audioRecordRunnable;
    private Thread audioThread;
    volatile boolean runAudioThread = true;

    /* video data getting thread */
    private Camera cameraDevice;
    private CameraView cameraView;

    private Frame yuvImage = null;

    /* layout setting */
    private final int bg_screen_bx = 232;
    private final int bg_screen_by = 128;
    private final int bg_screen_width = 700;
    private final int bg_screen_height = 500;
    private final int bg_width = 1123;
    private final int bg_height = 715;
    private final int live_width = 640;
    private final int live_height = 480;
    private int screenWidth, screenHeight;
    private Button btnRecorderControl;

    /* The number of seconds in the continuous record loop (or 0 to disable loop). */
    final int RECORD_LENGTH = 20;
    Frame[] images;
    long[] timestamps;
    ShortBuffer[] samples;
    int imagesIndex, samplesIndex;

    long firstTime = 0;
    long startPauseTime = 0;
    long totalPauseTime = 0;
    long pausedTime = 0;
    long stopPauseTime = 0;
    long totalTime = 0;

    long totalRecordedTS = 0;

    private TextView txtTimer;
    private Handler mHandler = new Handler();

    @Override
    public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

       setContentView(R.layout.touch_main);

       initLayout();
    }

    @Override
    protected void onDestroy() {
       super.onDestroy();

       recording = false;

       if (cameraView != null) {
           cameraView.stopPreview();
       }

       if (cameraDevice != null) {
           cameraDevice.stopPreview();
           cameraDevice.release();
           cameraDevice = null;
       }
    }


    private void initLayout() {

       /* get size of screen */
       Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
       screenWidth = display.getWidth();
       screenHeight = display.getHeight();
       RelativeLayout.LayoutParams layoutParam = null;
       LayoutInflater myInflate = null;
       myInflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
       RelativeLayout topLayout = new RelativeLayout(this);
       setContentView(topLayout);
       LinearLayout preViewLayout = (LinearLayout) myInflate.inflate(R.layout.touch_main, null);
       layoutParam = new RelativeLayout.LayoutParams(screenWidth, screenHeight);
       topLayout.addView(preViewLayout, layoutParam);

       txtTimer = (TextView) preViewLayout.findViewById(R.id.txtTimer);

       /* add control button: start and stop */
       btnRecorderControl = (Button) findViewById(R.id.recorder_control);
       btnRecorderControl.setText("Start");
       btnRecorderControl.setOnClickListener(this);

       /* add camera view */
       int display_width_d = (int) (1.0 * bg_screen_width * screenWidth / bg_width);
       int display_height_d = (int) (1.0 * bg_screen_height * screenHeight / bg_height);
       int prev_rw, prev_rh;
       if (1.0 * display_width_d / display_height_d > 1.0 * live_width / live_height) {
           prev_rh = display_height_d;
           prev_rw = (int) (1.0 * display_height_d * live_width / live_height);
       } else {
           prev_rw = display_width_d;
           prev_rh = (int) (1.0 * display_width_d * live_height / live_width);
       }
       layoutParam = new RelativeLayout.LayoutParams(prev_rw, prev_rh);
       layoutParam.topMargin = (int) (1.0 * bg_screen_by * screenHeight / bg_height);
       layoutParam.leftMargin = (int) (1.0 * bg_screen_bx * screenWidth / bg_width);

       cameraDevice = Camera.open();
       Log.i(LOG_TAG, "cameara open");
       cameraView = new CameraView(this, cameraDevice);
       topLayout.addView(cameraView, layoutParam);
       topLayout.setOnTouchListener(this);
       Log.i(LOG_TAG, "cameara preview start: OK");
    }

    //---------------------------------------
    // initialize ffmpeg_recorder
    //---------------------------------------
    private void initRecorder() {

       Log.w(LOG_TAG, "init recorder");

       if (RECORD_LENGTH > 0) {
           imagesIndex = 0;
           images = new Frame[RECORD_LENGTH * frameRate];
           timestamps = new long[images.length];
           for (int i = 0; i < images.length; i++) {
               images[i] = new Frame(destWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
               timestamps[i] = -1;
           }
       } else if (yuvImage == null) {
           yuvImage = new Frame(destWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
           Log.i(LOG_TAG, "create yuvImage");
       }
       Log.i(LOG_TAG, "ffmpeg_url: " + ffmpeg_link);
       recorder = new FFmpegFrameRecorder(ffmpeg_link, destWidth, imageHeight, 1);
       recorder.setFormat("mp4");
       recorder.setVideoCodecName("libx264");
       recorder.setSampleRate(sampleAudioRateInHz);
       // Set in the surface changed method
       recorder.setFrameRate(frameRate);

       Log.i(LOG_TAG, "recorder initialize success");

       audioRecordRunnable = new AudioRecordRunnable();
       audioThread = new Thread(audioRecordRunnable);
       runAudioThread = true;
    }

    public void startRecording() {

       initRecorder();

       mHandler.removeCallbacks(mUpdateTimeTask);
       mHandler.postDelayed(mUpdateTimeTask, 100);

       try {
           recorder.start();
           startTime = System.currentTimeMillis();
           recording = true;
           audioThread.start();

       } catch (FFmpegFrameRecorder.Exception e) {
           e.printStackTrace();
       }
    }

    public void stopRecording() {

       runAudioThread = false;
       try {
           audioThread.join();
       } catch (InterruptedException e) {
           e.printStackTrace();
       }
       audioRecordRunnable = null;
       audioThread = null;

       if (recorder != null && recording) {
           if (RECORD_LENGTH > 0) {
               Log.v(LOG_TAG, "Writing frames");
               try {
                   int firstIndex = imagesIndex % samples.length;
                   int lastIndex = (imagesIndex - 1) % images.length;
                   if (imagesIndex <= images.length) {
                       firstIndex = 0;
                       lastIndex = imagesIndex - 1;
                   }
                   if ((startTime = timestamps[lastIndex] - RECORD_LENGTH * 1000000L) < 0) {
                       startTime = 0;
                   }
                   if (lastIndex < firstIndex) {
                       lastIndex += images.length;
                   }
                   int videoCounter = 0;
                   for (int i = firstIndex; i <= lastIndex; i++) {
                       if (timestamps[i] == -1) {
                           Log.v(LOG_TAG, "frame not recorded");
                       }
                       if (timestamps[i] != -1) {
                           long t = timestamps[i % timestamps.length] - startTime;
                           if (t >= 0) {

                               videoCounter++;

                               /*if (((i % images.length) != 0) && images[i % images.length] != images[(i % images.length) - 1]) {
                                   if (t > recorder.getTimestamp()) {
                                       recorder.setTimestamp(t);
                                   }*/
                                   Log.v(LOG_TAG, "imageIndex=" + (i % images.length));
                                   recorder.record(images[i % images.length]);
                           /*    }*/
                               Log.v(LOG_TAG, "videoCounter=" + videoCounter);
                           }
                       }
                   }

                   firstIndex = samplesIndex % samples.length;
                   lastIndex = (samplesIndex - 1) % samples.length;
                   if (samplesIndex <= samples.length) {
                       firstIndex = 0;
                       lastIndex = samplesIndex - 1;
                   }
                   if (lastIndex < firstIndex) {
                       lastIndex += samples.length;
                   }
                   for (int i = firstIndex; i <= lastIndex; i++) {
                       if (timestamps[i] != -1) {
                           recorder.recordSamples(samples[i % samples.length]);
                       }
                   }
               } catch (FFmpegFrameRecorder.Exception e) {
                   Log.v(LOG_TAG, e.getMessage());
                   e.printStackTrace();
               }
           }

           recording = false;
           Log.v(LOG_TAG, "Finishing recording, calling stop and release on recorder");
           try {
               recorder.stop();
               recorder.release();
           } catch (FFmpegFrameRecorder.Exception e) {
               e.printStackTrace();
           }
           recorder = null;

       }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

       if (keyCode == KeyEvent.KEYCODE_BACK) {
           if (recording) {
               stopRecording();
           }

           finish();

           return true;
       }

       return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
       switch (motionEvent.getAction()) {
           case MotionEvent.ACTION_DOWN:
               Log.v(LOG_TAG, "ACTION_DOWN" + recording);

               if (!recording) {
                   startRecording();
               } else {
                   stopPauseTime = System.currentTimeMillis();
                   totalPauseTime = stopPauseTime - startPauseTime - ((long) (1.0 / (double) frameRate) * 1000);
                   pausedTime += totalPauseTime;
               }
               rec = true;
               setTotalVideoTime();
               btnRecorderControl.setText(getResources().getString(R.string.stop));
               break;
           case MotionEvent.ACTION_MOVE:
               rec = true;
               setTotalVideoTime();
               break;
           case MotionEvent.ACTION_UP:
               Log.v(LOG_TAG, "ACTION_UP");
               rec = false;
               startPauseTime = System.currentTimeMillis();
               break;
       }
       return true;
    }

    private Runnable mUpdateTimeTask = new Runnable() {
       public void run() {
           if (recording) {
               setTotalVideoTime();
           }
           mHandler.postDelayed(this, 500);
       }
    };

    private synchronized void setTotalVideoTime() {
       totalTime = System.currentTimeMillis() - firstTime - pausedTime - ((long) (1.0 / (double) frameRate) * 1000);
       if (totalTime > 0)
           txtTimer.setText(getRecordingTimeFromMillis(totalTime));
    }

    private String getRecordingTimeFromMillis(long millis) {
       String strRecordingTime = null;
       int seconds = (int) (millis / 1000);
       int minutes = seconds / 60;
       int hours = minutes / 60;

       if (hours >= 0 && hours < 10)
           strRecordingTime = "0" + hours + ":";
       else
           strRecordingTime = hours + ":";

       if (hours > 0)
           minutes = minutes % 60;

       if (minutes >= 0 && minutes < 10)
           strRecordingTime += "0" + minutes + ":";
       else
           strRecordingTime += minutes + ":";

       seconds = seconds % 60;

       if (seconds >= 0 && seconds < 10)
           strRecordingTime += "0" + seconds;
       else
           strRecordingTime += seconds;

       return strRecordingTime;

    }


    //---------------------------------------------
    // audio thread, gets and encodes audio data
    //---------------------------------------------
    class AudioRecordRunnable implements Runnable {

       @Override
       public void run() {
           android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);

           // Audio
           int bufferSize;
           ShortBuffer audioData;
           int bufferReadResult;

           bufferSize = AudioRecord.getMinBufferSize(sampleAudioRateInHz,
                   AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
           audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleAudioRateInHz,
                   AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);

           if (RECORD_LENGTH > 0) {
               samplesIndex = 0;
               samples = new ShortBuffer[RECORD_LENGTH * sampleAudioRateInHz * 2 / bufferSize + 1];
               for (int i = 0; i < samples.length; i++) {
                   samples[i] = ShortBuffer.allocate(bufferSize);
               }
           } else {
               audioData = ShortBuffer.allocate(bufferSize);
           }

           Log.d(LOG_TAG, "audioRecord.startRecording()");
           audioRecord.startRecording();

           /* ffmpeg_audio encoding loop */
           while (runAudioThread) {
               if (RECORD_LENGTH > 0) {
                   audioData = samples[samplesIndex++ % samples.length];
                   audioData.position(0).limit(0);
               }
               //Log.v(LOG_TAG,"recording? " + recording);
               bufferReadResult = audioRecord.read(audioData.array(), 0, audioData.capacity());
               audioData.limit(bufferReadResult);
               if (bufferReadResult > 0) {
                   Log.v(LOG_TAG, "bufferReadResult: " + bufferReadResult);
                   // If "recording" isn't true when start this thread, it never get's set according to this if statement...!!!
                   // Why?  Good question...
                   if (recording && rec) {
                       Log.v(LOG_TAG, "Recording audio");
                       if (RECORD_LENGTH <= 0) try {
                           recorder.recordSamples(audioData);
                           //Log.v(LOG_TAG,"recording " + 1024*i + " to " + 1024*i+1024);
                       } catch (FFmpegFrameRecorder.Exception e) {
                           Log.v(LOG_TAG, e.getMessage());
                           e.printStackTrace();
                       }
                   }
               }
           }
           Log.v(LOG_TAG, "AudioThread Finished, release audioRecord");

           /* encoding finish, release recorder */
           if (audioRecord != null) {
               audioRecord.stop();
               audioRecord.release();
               audioRecord = null;
               Log.v(LOG_TAG, "audioRecord released");
           }
       }
    }

    //---------------------------------------------
    // camera thread, gets and encodes video data
    //---------------------------------------------
    class CameraView extends SurfaceView implements SurfaceHolder.Callback, PreviewCallback {

       private SurfaceHolder mHolder;
       private Camera mCamera;

       public CameraView(Context context, Camera camera) {
           super(context);
           Log.w("camera", "camera view");
           mCamera = camera;
           mHolder = getHolder();
           mHolder.addCallback(CameraView.this);
           mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
           mCamera.setPreviewCallback(CameraView.this);
       }

       @Override
       public void surfaceCreated(SurfaceHolder holder) {
           try {
               stopPreview();
               mCamera.setPreviewDisplay(holder);
           } catch (IOException exception) {
               mCamera.release();
               mCamera = null;
           }
       }

       public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
           stopPreview();

           Camera.Parameters camParams = mCamera.getParameters();
           List sizes = camParams.getSupportedPreviewSizes();
           // Sort the list in ascending order
           Collections.sort(sizes, new Comparator() {

               public int compare(final Camera.Size a, final Camera.Size b) {
                   return a.width * a.height - b.width * b.height;
               }
           });

           camParams.setPreviewSize(imageWidth, imageHeight);

           Log.v(LOG_TAG, "Setting imageWidth: " + imageWidth + " imageHeight: " + imageHeight + " frameRate: " + frameRate);

           camParams.setPreviewFrameRate(frameRate);
           Log.v(LOG_TAG, "Preview Framerate: " + camParams.getPreviewFrameRate());

           mCamera.setParameters(camParams);

           List videoSizes = mCamera.getParameters().getSupportedVideoSizes();

           // Set the holder (which might have changed) again
           try {
               mCamera.setPreviewDisplay(holder);
               mCamera.setPreviewCallback(CameraView.this);
               startPreview();
           } catch (Exception e) {
               Log.e(LOG_TAG, "Could not set preview display in surfaceChanged");
           }
       }

       @Override
       public void surfaceDestroyed(SurfaceHolder holder) {
           try {
               mHolder.addCallback(null);
               mCamera.setPreviewCallback(null);
           } catch (RuntimeException e) {
               // The camera has probably just been released, ignore.
           }
       }

       public void startPreview() {
           if (!isPreviewOn && mCamera != null) {
               isPreviewOn = true;
               mCamera.startPreview();
           }
       }

       public void stopPreview() {
           if (isPreviewOn && mCamera != null) {
               isPreviewOn = false;
               mCamera.stopPreview();
           }
       }

       @Override
       public void onPreviewFrame(byte[] data, Camera camera) {
           if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
               startTime = System.currentTimeMillis();
               return;
           }
           if (RECORD_LENGTH > 0) {
               int i = imagesIndex++ % images.length;
               Log.v(LOG_TAG, "recording:" + recording + "rec:" + rec);
               if (recording && rec) {
                   yuvImage = images[i];
                   timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
                   totalRecordedTS++;
               } else {
                   Log.v(LOG_TAG, "recording is paused");
                   yuvImage = null;
                   timestamps[i] = -1;
               }
           }

           /* get video data */
           if (yuvImage != null && recording && rec) {
               if (data.length != imageWidth * imageHeight) {
                   Camera.Size sz = camera.getParameters().getPreviewSize();
                   imageWidth = sz.width;
                   imageHeight = sz.height;
                   destWidth = imageHeight;
                   Log.v(LOG_TAG, "data length:" + data.length);
               }

               ByteBuffer bb = (ByteBuffer) yuvImage.image[0].position(0); // resets the buffer
               int start = 2 * ((imageWidth - destWidth) / 4); // this must be even
               for (int row = 0; row < imageHeight * 3 / 2; row++) {
                   bb.put(data, start, destWidth);
                   start += imageWidth;
               }

           }
       }
    }

    @Override
    public void onClick(View v) {
       if (!recording) {
           startRecording();
           Log.w(LOG_TAG, "Start Button Pushed");
           btnRecorderControl.setText("Stop");
       } else {
           // This will trigger the audio recording loop to stop and then set isRecorderStart = false;
           stopRecording();
           Log.w(LOG_TAG, "Stop Button Pushed");
           btnRecorderControl.setText("Start");
       }
    }}

    Changes made as per Alex Cohn’s suggestions

    Suggestion 1 - Estimate average frame rate

       public void stopRecording() {

      ..............................

                               if (((i % images.length) != 0) && images[i % images.length] != images[(i % images.length) - 1]) {
                                   if (t > recorder.getTimestamp()) {
                                       t += 1000000 / frameRate;
                                       recorder.setTimestamp(t);
                                   }

                                   recorder.record(images[i % images.length]);
                               }
                ..........................................


    }

    Change made was adding t += 1000000 / frameRate ; But this caused the video to freeze (as in case 1 described above) in portions when finger was placed away from screen.

    Suggestion 2 - Modification in onPreviewFrame()

    long[] timestampsForRecorder;
    private void initRecorder() {

       Log.w(LOG_TAG, "init recorder");

       if (RECORD_LENGTH > 0) {
          .......................................................
           timestampsForRecorder = new long[images.length];
           for (int i = 0; i < images.length; i++) {
               images[i] = new Frame(destWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
               timestamps[i] = -1;
               timestampsForRecorder[i] = -1;
           }
       } else if (yuvImage == null) {
           yuvImage = new Frame(destWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
           Log.i(LOG_TAG, "create yuvImage");
       }
       ...................................................
    }

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
           if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
               startTime = SystemClock.elapsedRealtime();
               return;
           }
           if (RECORD_LENGTH > 0) {
               int i = imagesIndex++ % images.length;
               Log.v(LOG_TAG, "recording:" + recording + "rec:" + rec);
               if (recording && rec) {
                   yuvImage = images[i];
                   long thisFrameTime = SystemClock.elapsedRealtime();
                   timestamps[i] = thisFrameTime;
                   long lastFrameTime = timestamps[(int) (imagesIndex == 0 ? startTime : ((imagesIndex-1) % images.length))];
                   Log.v(LOG_TAG, "lastFrameTime:" + lastFrameTime+",stopPauseTime:" + stopPauseTime);
                   if (lastFrameTime > stopPauseTime) {
                       timestampsForRecorder[i] = 1000 * (thisFrameTime - Math.max(stopPauseTime, lastFrameTime));
                   }
               }
           }

          .....................................................
       }

    public void stopRecording() {

       .......................................................

       if (recorder != null && recording) {
           if (RECORD_LENGTH > 0) {
               Log.v(LOG_TAG, "Writing frames");
               try {
                   int firstIndex = imagesIndex % samples.length;
                   int lastIndex = (imagesIndex - 1) % images.length;
                   if (imagesIndex <= images.length) {
                       firstIndex = 0;
                       lastIndex = imagesIndex - 1;
                   }
                   if ((startTime = timestampsForRecorder[lastIndex] - RECORD_LENGTH * 1000000L) < 0) {
                       startTime = 0;
                   }
                   if (lastIndex < firstIndex) {
                       lastIndex += images.length;
                   }
                   for (int i = firstIndex; i <= lastIndex; i++) {

                       if (timestampsForRecorder[i] != -1) {
                           long t = timestampsForRecorder[i % timestampsForRecorder.length] - startTime;
                           if (t >= 0) {

                               if (((i % images.length) != 0) && images[i % images.length] != images[(i % images.length) - 1]) {
                                   if (t > recorder.getTimestamp()) {
                                       recorder.setTimestamp(t);
                                   }
                                   Log.v(LOG_TAG, "imageIndex=" + (i % images.length));
                                   recorder.record(images[i % images.length]);
                               }
                           }
                       }
                   }
                   .............................................
               } catch (FFmpegFrameRecorder.Exception e) {
                  .................................
               }
           }

           ...........................................

       }
    }

    The video recorded using this was having the issue in case 2 mentioned above. ie,It was playing at a faster rate

  • Issue in recording video

    16 novembre 2015, par human123

    I am trying to record video in 480*480 resolution like in vine using javacv. As a starting point I used the sample provided in https://github.com/bytedeco/javacv/blob/master/samples/RecordActivity.java Video is getting recorded (but not in the desired resolution) and saved.

    But the issue is that 480*480 resolution is not supported natively in android. So some pre processing needs to be done to get the video in desired resolution.

    So once I was able to record video using code sample provided by javacv, next challenge was on how to pre process the video. On research it was found that efficient cropping is possible when final image width required is same as recorded image width. Such a solution was provided in the SO question,Recording video on Android using JavaCV (Updated 2014 02 17). I changed onPreviewFrame method as suggested in that answer.

       @Override
       public void onPreviewFrame(byte[] data, Camera camera) {
           if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
               startTime = System.currentTimeMillis();
               return;
           }
           if (RECORD_LENGTH > 0) {
               int i = imagesIndex++ % images.length;
               yuvImage = images[i];
               timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
           }
           /* get video data */
           imageWidth = 640;
           imageHeight = 480    
           int finalImageHeight = 360;
           if (yuvImage != null && recording) {
               ByteBuffer bb = (ByteBuffer)yuvImage.image[0].position(0); // resets the buffer
               final int startY = imageWidth*(imageHeight-finalImageHeight)/2;
               final int lenY = imageWidth*finalImageHeight;
               bb.put(data, startY, lenY);
               final int startVU = imageWidth*imageHeight + imageWidth*(imageHeight-finalImageHeight)/4;
               final int lenVU = imageWidth* finalImageHeight/2;
               bb.put(data, startVU, lenVU);
               try {
                   long t = 1000 * (System.currentTimeMillis() - startTime);
                   if (t > recorder.getTimestamp()) {
                       recorder.setTimestamp(t);
                   }
                   recorder.record(yuvImage);
               } catch (FFmpegFrameRecorder.Exception e) {
                   Log.e(LOG_TAG, "problem with recorder():", e);
               }
           }


       }
    }

    Please also note that this solution was provided for an older version of javacv. The resulting video had a yellowish overlay covering 2/3rd part. Also there was empty section on left side as the video was not cropped correctly.

    So my question is what is the most appropriate solution for cropping videos using latest version of javacv ?

    Code after making change as suggested by Alex Cohn

       @Override
       public void onPreviewFrame(byte[] data, Camera camera) {
           if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
               startTime = System.currentTimeMillis();
               return;
           }
           if (RECORD_LENGTH > 0) {
               int i = imagesIndex++ % images.length;
               yuvImage = images[i];
               timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
           }
           /* get video data */
           imageWidth = 640;
           imageHeight = 480;      
           destWidth = 480;

           if (yuvImage != null && recording) {
               ByteBuffer bb = (ByteBuffer)yuvImage.image[0].position(0); // resets the buffer
               int start = 2*((imageWidth-destWidth)/4); // this must be even
               for (int row=0; row2; row++) {
                   bb.put(data, start, destWidth);
                   start += imageWidth;
               }
               try {
                   long t = 1000 * (System.currentTimeMillis() - startTime);
                   if (t > recorder.getTimestamp()) {
                       recorder.setTimestamp(t);
                   }
                   recorder.record(yuvImage);
               } catch (FFmpegFrameRecorder.Exception e) {
                   Log.e(LOG_TAG, "problem with recorder():", e);
               }
           }


       }

    Screen shot from video generated with this code (destWidth 480) is

    video resolution 480*480

    Next I tried capturing a video with destWidth speciified as 639. The result is

    639*480

    When destWidth is 639 video is repeating contents twice. When it is 480, contents are repeated 5 times and the green overlay and distortion is more.

    Also When the destWidth = imageWidth, video is captured properly. ie, for 640*480 there is no repetition of video contents and no green overlay.

    Converting frame to IplImage

    When this question was asked first, I missed to mention that the record method in FFmpegFrameRecorder is now accepting object of type Frame whereas earlier it was IplImage object. So I tried to apply Alex Cohn’s solution by converting Frame to IplImage.

    //---------------------------------------
    // initialize ffmpeg_recorder
    //---------------------------------------
    private void initRecorder() {

       Log.w(LOG_TAG,"init recorder");

       imageWidth = 640;
       imageHeight = 480;

       if (RECORD_LENGTH > 0) {
           imagesIndex = 0;
           images = new Frame[RECORD_LENGTH * frameRate];
           timestamps = new long[images.length];
           for (int i = 0; i < images.length; i++) {
               images[i] = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
               timestamps[i] = -1;
           }
       } else if (yuvImage == null) {
           yuvImage = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
           Log.i(LOG_TAG, "create yuvImage");
           OpenCVFrameConverter.ToIplImage converter = new OpenCVFrameConverter.ToIplImage();
           yuvIplimage = converter.convert(yuvImage);

       }

       Log.i(LOG_TAG, "ffmpeg_url: " + ffmpeg_link);
       recorder = new FFmpegFrameRecorder(ffmpeg_link, imageWidth, imageHeight, 1);
       recorder.setFormat("flv");
       recorder.setSampleRate(sampleAudioRateInHz);
       // Set in the surface changed method
       recorder.setFrameRate(frameRate);

       Log.i(LOG_TAG, "recorder initialize success");

       audioRecordRunnable = new AudioRecordRunnable();
       audioThread = new Thread(audioRecordRunnable);
       runAudioThread = true;
    }



    @Override
       public void onPreviewFrame(byte[] data, Camera camera) {
           if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
               startTime = System.currentTimeMillis();
               return;
           }
           if (RECORD_LENGTH > 0) {
               int i = imagesIndex++ % images.length;
               yuvImage = images[i];
               timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
           }
           /* get video data */
           int destWidth = 640;

           if (yuvIplimage != null && recording) {
               ByteBuffer bb = yuvIplimage.getByteBuffer(); // resets the buffer
               int start = 2*((imageWidth-destWidth)/4); // this must be even
               for (int row=0; row2; row++) {
                   bb.put(data, start, destWidth);
                   start += imageWidth;
               }
               try {
                   long t = 1000 * (System.currentTimeMillis() - startTime);
                   if (t > recorder.getTimestamp()) {
                       recorder.setTimestamp(t);
                   }
                   recorder.record(yuvImage);
               } catch (FFmpegFrameRecorder.Exception e) {
                   Log.e(LOG_TAG, "problem with recorder():", e);
               }
           }


       }

    But the videos generated with this method contained only green frames.

  • Modify H.264 Level in MP4 stream

    25 mars 2013, par d33pika

    I have 1000+ videos with wrong Level information, and hence do not play on some devices. They are H.264 baseline with aac audio in mp4 container. I want to correct them but avoid re-encoding. Am I right in assuming that this is possible and will be faster ? How do I identify the level_idc bits in the streams ? Will all streams have them in the same location ? I expect this to be in just one place in the stream, is this assumption correct ?
    Update : I came across a windows executable link that claims to do this. I want to be able to do this commandline on unix, so I can script it.

    More Updates : As per Roman's answer below. I dug up MP4 syntax and found that Profile and Level information are part of avcC atom under stsd. I could see that level was set to 1E, I corrected it to 1F. Before :

    61 76 63 43 01 42 C0 1E FF E1 00 19 67 42 C0 1E
    D9

    After :

    61 76 63 43 01 42 C0 1F FF E1 00 19 67 42 C0 1E
    D9

    with that the MediaInfo changed to :

    Video
    ID                                       : 1
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : Baseline@L3.0
    Format settings, CABAC                   : No
    Format settings, ReFrames                : 3 frames
    Muxing mode                              : Container profile=Baseline@3.1
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 1mn 4s
    Bit rate                                 : 3 000 Kbps
    Width                                    : 1 280 pixels
    Height                                   : 720 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 30.000 fps
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.109
    Stream size                              : 22.7 MiB (92%)
    Writing library                          : x264 core 120 r2151 a3f4407
    Encoding settings                        : cabac=0 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=3000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

    It introduced a Muxing mode parameter with level 3.1 but alas this stream did not play on the device either. How do I correct the level indicated in Format Profile Is this possible without re-encoding ?