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• How To convert video 16:9 to 4:3 with black bar with ffmpeg

  1er juin 2021, par VengenzR

  ok i trying to convert 16:9 videos to 4:3(PAL 720x576) but i getting this error , any solution ?

  


  [Parsed_pad_0 @ 0x55d70679c4c0] Failed to configure input pad on Parsed_pad_0
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0  

ffmpeg -i input.mp4 -vf pad=720:480:0:38 -f dvd -target pal-dvd -aspect 4:3 -vb 8000kb  outputname.mpg ```


  


• Unable to create custom mobile-ffmpeg

  29 mai 2021, par Olcay Karabıyık

  I've been trying to find the way but I'm unable to create a custom mobile-ffmpeg for react-native-ffmpeg for iOS and Android. Please Help.

  


• Custom Reading Function for FFMPEG I/O

  20 septembre 2015, par Joe Allen

  I need to create a custom reading callback function that can read contents of a file in the form of a std::string into a uint8_t * buf. I tried multiple different methods found around the internet and on stackoverflow but sometimes it works and other the the program infinitely loops or stops execution half way.

  I have no problems with amr/3gp files but all wav/pcm files are causing some problems for some reason. All I know its something to do with the reading function I have so far.

  Ideally I would like to be able to give the program any type of file and then it converts it.

  This is how I am calling the readCallback function from the code :

  //create the buffer
  
  uint8_t * avio_ctx_buffer = NULL;
  
  
  
  //allocate space for the buffer using ffmpeg allocation method
  
  avio_ctx_buffer = (uint8_t *) av_malloc(avio_ctx_buffer_size);
  
  
  
  //Allocate and initialize an AVIOContext for buffered I/O.
  
  //audio variable contains the contents of the audio file
  
  avio_ctx = avio_alloc_context(avio_ctx_buffer, avio_ctx_buffer_size,0, &audio, &readCallback, NULL, NULL);

  Here is the callback function that works on some types of files :

  static int readCallback(void* opaque, uint8_t * buf, int buf_size){  
  
    std::string * file =static_cast(opaque);
  
    if(file->length() == 0){
  
     return AVERROR_EOF; //if we reach to the end of the string, return
  
                         // return End of file
  
    }
  
  
  
    // Creating a vector of the string size
  
    std::vector array(file->length());
  
  
  
    //Copying the contents of the string into the vector
  
    std::copy(file->begin(),file->end(),array.begin());
  
  
  
    //Copying the vector into buf
  
    std::copy(array.begin(),array.end(),buf);
  
  
  
  
  
    return file->length();
  
  
  
  }