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• How to get video frames from mp4 video using ffmpeg in android ?

  3 juin 2013, par Mihir Shah

  I have successfully compiled and build ffmpeg library in android after 3,4 days research work.
  Now I want to grab frames from video. But I don't know which ffmpeg method with command to be called from java class to grab the all frames. Any one have idea about it ? or I want to overlay 2 videos. Is there any direct method available in ffmpeg to merge two videos one over another ? If yes, how to call it from java class ?

• Building FFmpeg for Android to use command line arguments

  28 juin 2013, par Zargoon

  I am trying to build the FFmpeg library to use in my android app with the NDK. The reason for this is because I am using the native video capture feature in android because I really don't want to write my own video recorder. However, the native video capture only allows for either high-quality encoding, or low quality encoding. I want something in between, and I believe that the solution is to use the FFmpeg library to re-encode the high quality video to be lighter.

  So far I have been able to build the FFmpeg library according to this guide : http://www.roman10.net/how-to-build-ffmpeg-for-android/ and which a few tweaks I have been able to get it to work.

  However, everything that I've found seems to be about writing your own encoder, which seems like overkill to me. All that I really want to do is send a string in command line format to the main() function of FFmpeg and re-encode my video. However, I can't seem to figure out how I build FFmpeg to give me access to the main method. I found this post : Compile ffmpeg.c and call its main() via JNI which links to a project doing what I want more of less, but for the life of me I cannot figure out what is going on. It also seems like he is compiling more than I want, and I would really like to keep my application as light weight as possible.

  Some additional direction would be extremely helpful. Thank you.

• Running ffmpeg commands from android ffmpeg syntax error in logcat

  30 septembre 2015, par Chaitanya Chandurkar

  I have successfully compiled ffmpeg for android and have ported it.

  I placed

  1. libffmpeg.so in /system/lib directory
  2. ffmpeg executable in /system/bin and /system/xbin directory (i was not sure where to place it). i directly copied ffmpeg executable from source directory (Not sure whether it’s a correct way)

  Now i am executing commands from android with following code !!

  imports *
  
  public class LatestActivity extends Activity {
  
  
  
      private Process process;
  
      String command,text;
  
  
  
      static { 
  
          System.loadLibrary("ffmpeg");
  
      }
  
  
  
    @Override
  
      public void onCreate(Bundle savedInstanceState) {
  
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.activity_latest);
  
  
  
            //Execute Command !!  
  
            try {
  
                 Execute();
  
            } catch (IOException e) {
  
                // TODO Auto-generated catch block
  
                e.printStackTrace();
  
            } catch (InterruptedException e) {
  
                 // TODO Auto-generated catch block
  
                  e.printStackTrace();
  
            }
  
       }
  
  
  
  
  
  
  
  
  
  public void Execute() throws IOException, InterruptedException{
  
          try {
  
              File dir=new File("/system/bin");
  
              String[] cmd= {"ffmpeg","-codecs"};
  
  
  
              process=Runtime.getRuntime().exec(cmd,null,dir);
  
          } catch (IOException e) {
  
              // TODO Auto-generated catch block
  
              Log.d("Process IOException starts:",e.getMessage());
  
              e.printStackTrace();
  
              Log.d("System Manual exit !!",e.getMessage());
  
              System.exit(MODE_PRIVATE);
  
          }
  
  
  
          BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()),16384);
  
  
  
           BufferedReader stdError = new BufferedReader(new InputStreamReader(process.getErrorStream()));
  
  
  
             // read the output from the command
  
             Log.d("Application output: ","Output if any !"); 
  
              while ((text = stdInput.readLine()) != null) {
  
                  Log.d("Output: ",text); //$NON-NLS-1$
  
                 }
  
  
  
  
  
          text="";
  
             // read any errors from the attempted command
  
          Log.d("Application output: ","Errors if any !");  //$NON-NLS-1$
  
             while ((text = stdError.readLine()) != null) {
  
  
  
                 Log.d("Error: ",text);  //$NON-NLS-1$
  
             }
  
  
  
  
  
  
  
             stdInput.close();
  
             stdError.close();
  
  
  
             process.waitFor();
  
             process.getOutputStream().close();
  
             process.getInputStream().close();
  
             process.getErrorStream().close(); 
  
             destroyProcess(process);
  
             //process.destroy();
  
  
  
      }
  
  
  
      private static void destroyProcess(Process process) {
  
          try {
  
              if (process != null) {
  
                  // use exitValue() to determine if process is still running.
  
                  process.exitValue();
  
              }
  
          } catch (IllegalThreadStateException e) {
  
              // process is still running, kill it.
  
              process.destroy();
  
          }
  
      }
  
  
  
    }

  And Here is the logcat output :

  09-05 15:29:13.287: D/dalvikvm(2670): No JNI_OnLoad found in /system/lib/libffmpeg.so 0x44e7e910, skipping init
  
  09-05 15:29:29.117: I/global(2670): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
  
  09-05 15:29:29.117: D/Application output:(2670): Output if any !
  
  09-05 15:29:29.117: D/Application output:(2670): Errors if any !
  
  09-05 15:29:29.127: D/Error:(2670): /system/bin/ffmpeg: 1: Syntax error: "(" unexpected

  m neither getting any errors nor output of command.
  At the end it shows syntax error.
  I want to know what kind of syntax error it is. how to tackle it ?

  m i doing something wrong ?