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• timecode of scene change detection ffmpeg

  16 mars 2015, par Михаил Боровинских

  Good day, there was a bit of a problem when I working with ffmpeg. We need to find timecodes of scene change detection in the video. Use the following command :

  ffmpeg -i inputVideo.mp4 -f image2 -vf "select = gt (scene \ ,. 5)" -vsync vfr thumb% 04d.png

  It creates an image from scene change detection. I do not know how to add timecode to a text file. Thanks in advance for your help !)

  P.S. Sorry for my bad english)

• Distributed video decoding over a network

  26 mars 2015, par tkcast

  i’m developing a videowall controller.
  I can use any technology of programming language needed, and I want to decode videos of arbitrarily high resolution on my videowall.

  One possible solution is :
   split the ultra high video into several slices using ffmpeg and have one computer to decode each tile of the videowall separately. I’d use the network only to control the playback

  Another interesting solution :
   only a master computer would have the huge video, and it would control a distributed decoding over the network. Is it even possible ? how ?

  Thanks !

• Remove the instance of native library from app using dlclose(Android NDK)

  7 septembre 2012, par mirroredAbstraction

  I have compiled FFmpeg library using NDK and use it to trim videos and get thumbnails from a video in my app, so basically I have ffmpeg.so and video-trimmer.so libraries up and running.

  The problem however is strange, the trim or getThumbnail operations are successful but just one time i.e. the first time and the operations fail the second time. However it is successful the third time, I googled it and got two similar posts on SO related to my problem

  POST 1 :

  POST 2 :

  Interestingly they suggest the same solution and I am unable to solve the issue being a naive in C programming language.

  Here is what I have done

  void Java_com_example_demo_natives_LibraryLoader_loadTrimmerLibrary(JNIEnv* env, jclass class, jstring libffmpeg_path, jstring inputFile, jstring outFile,
  
          jstring startTime, jstring length)
  
  {
  
          const char* path;
  
          void* handle;
  
          int *(*Java_com_example_demo_natives_VideoTrimmer_trim)(JNIEnv *, jclass, jstring, jstring, jstring, jstring);
  
  
  
          path = (*env)->GetStringUTFChars(env, libffmpeg_path, 0);
  
  
  
          handle = dlopen(path, RTLD_LAZY);
  
  
  
          Java_com_example_demo_natives_VideoTrimmer_trim = dlsym(handle, "Java_com_example_demo_natives_VideoTrimmer_trim");
  
          (*Java_com_example_demo_natives_VideoTrimmer_trim)(env, class, inputFile, outFile, startTime, length);
  
  
  
          (*env)->ReleaseStringUTFChars(env, libffmpeg_path, path);
  
  
  
          dlclose(handle);
  
  }

  Despite of calling dlclose the library instance still exists in memory, what I am doing wrong here ?

  I come to know that library instance still exists because when I load the libraries again in some other activity the error message says library already exists in CL.

  I want to get rid of the instance of that library from memory, please help...