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• FFMPEG & OPENGL - RAW Frames

  27 mars 2015, par Marco Reisacher

  I’m building a recorder using a BlackMagic DeckLink Card.
  The program is using OpenGL to display the Frames and FFMPEG (with the glReadPixels() method) to record them.
  I’m setting the viewport in my program to apply a automatic letter-/pillarbox whether the Image/Monitor is 16:9/4:3.
  The problem with that ist that when i capture these frames of this viewport they get of course recorded in the resolution my viewport is (i.e. Full Hd source -> viewport due to monitor with 1600x1200 resolution -> letterbox down to 1600x900) and so FFMPEG records those 1600x1200 with black bars at the top/bottom.

  Is there any possibility to grab the RAW Frame before it gets passed trough the setViewport function and all the rescaling stuff ?

• geting no result from GetStringUTFChars JNI

  9 avril 2013, par talhamalik22

  android NDK for my android application. i am stuck on the starting lines and it is not compiling further. Following is my code. It doest not compile after "str = (*env)->GetStringUTFChars(env, filename, NULL) ;". Please check my java and c code

  The java code :

  public class MyffmpegActivity extends Activity {
  
  
  
  private static native int logFileInfo(String filename);
  
  
  
  static
  
  {
  
      Log.i("HEHA", "HOHA");
  
      System.loadLibrary("mylib");
  
  }
  
  
  
  @Override
  
  protected void onCreate(Bundle savedInstanceState) {
  
      super.onCreate(savedInstanceState);
  
      setContentView(R.layout.activity_myffmpeg);
  
      String path=Environment.getExternalStorageDirectory().getPath();
  
      path=path+"/test.mp4";
  
      Log.i("Name Returned is ", ":"+path);
  
  int x=logFileInfo(path);
  
  
  
  
  
  }

  The C code

  jint Java_com_example_myffmpegtest_MyffmpegActivity_logFileInfo(JNIEnv * env, jobject  this, jstring filename)
  
  {
  
  
  
  av_register_all();
  
     AVFormatContext *pFormatCtx;
  
     const jbyte *str;
  
  
  
    str = (*env)->GetStringUTFChars(env, filename, NULL);
  
   if(av_open_input_file(&pFormatCtx, str, NULL, 0, NULL)!=0)
  
   {
  
      LOGE("Can't open file '%s'\n", str);
  
      return 1;
  
  }
  
  else
  
  {
  
  
  
      LOGI("File was opened\n");
  
      LOGI("File '%s', Codec %s",
  
          pFormatCtx->filename,
  
          pFormatCtx->iformat->name
  
      );
  
  }
  
  return 0;}

• Where is my ffmpeg stream getting saved to ?

  14 mars 2013, par Chris

  I'm just starting to explore ffmpeg (ultimately for use with openCV), and I'm running this command :

  root@beaglebone:/# ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 /out.avi

  At which point the camera indicator light turns on and it appears to be capturing. However when I end it with CTRL+C, the file is nowhere to be found.

  Any thoughts ?

  Full output :

  root@beaglebone:/# ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 /out.avi
  
  ffmpeg version v0.7.4, Copyright (c) 2000-2011 the Libav developers
  
    built on Oct  9 2012 10:50:57 with gcc 4.5.4 20120305 (prerelease)
  
    configuration: --enable-shared --enable-pthreads --enable-gpl --enable-postproc --enable-avfilter --cross-prefix=arm-angstrom-linux-gnueabi- --prefix=/usr --enable-ffserver --enable-ffplay --enable-x11grab --enable-libtheora --enable-libvorbis --arch=arm --target-os=linux --enable-cross-compile --extra-cflags=' -fexpensive-optimizations -fomit-frame-pointer -O4 -ffast-math -march=armv7-a -fno-tree-vectorize -mthumb-interwork -mfloat-abi=softfp -mfpu=neon -mtune=cortex-a8 --sysroot=/home/koen/setup-scripts/build/tmp-angstrom_v2012_05-eglibc/sysroots/beaglebone' --extra-ldflags='-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed' --sysroot=/home/koen/setup-scripts/build/tmp-angstrom_v2012_05-eglibc/sysroots/beaglebone --enable-hardcoded-tables --cpu=cortex-a8
  
    libavutil    51.  7. 0 / 51.  7. 0
  
    libavcodec   53.  6. 0 / 53.  6. 0
  
    libavformat  53.  3. 0 / 53.  3. 0
  
    libavdevice  53.  0. 0 / 53.  0. 0
  
    libavfilter   2.  4. 0 /  2.  4. 0
  
    libswscale    2.  0. 0 /  2.  0. 0
  
    libpostproc  52.  0. 0 / 52.  0. 0
  
  ^C
  
  root@beaglebone:/# ls
  
  bin   dev  home  lost+found  mnt  proc  sbin  tmp  var
  
  boot  etc  lib   media       opt  run   sys   usr
  
  root@beaglebone:/#