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• What does it mean for avcodec_find_decoder() to return 0 ? [duplicate]

  11 février 2019, par Lucas Zanella

  This question already has an answer here :

  • ffmpeg compilation problem : avcodec_find_decoder always returns null
    
    2 answers
    

  This part of my code

  m_pAVCodec = avcodec_find_decoder(AV_CODEC_ID_H264);

  is returning 0, which means it failed to find the codec.

  What does it mean for ffmpeg to not find a codec ? Is it something related with my system ? I need somehow to install the h264 codec ?

  I’m using Ubuntu

  UPDATE :

  By doing
  avcodec_register_all() ;

  before, it works. It’s kinda strange because av_register_all() was deprecated long ago and won’t even compile.

  What more needs to be registered ?

• PHP exec or shell_exec not returning process id (PID) on Windows Wamp

  17 mai 2013, par HoplaYann

  I am on windows 7, using a WampServer, and trying to use FFMPEG.

  The encoding works, but I can't get a process id back from either the exec()
  method nor the shell_exec() methods.

  This is my code :

  $cmd = C:\ffmpeg\bin\ffmpeg.exe -i "C:\...\4ch.wav"  -ar 44100 -ab 48000 -f mp3 -y "C:\...\enc_4ch.mp3"

  This what I was trying to do with shell_exec :

  shell_exec("nohup $cmd > /dev/null & echo $!");

  And with exec :

  exec("nohup " . $this->_command . " > /dev/null 2>/dev/null &") ; // returns null
  
  exec("nohup " . $this->_command . " > /dev/null 2>&1 &"); // also returns null 

  Please let me know what I do wrong, as I'd like later to use the following method to check if my process is still running :

  private function is_process_running($proccess_id) 
  
      { 
  
          exec("ps $proccess_id", $process_state);
  
          return (count($process_state) >= 2);
  
      }

  thank you in advace

• avformat_open_input return value, error code on NaCl Module

  7 février 2016, par Jar

  I’m trying to port FFmpeg into my NaCl module.

  So far, my module linked ffmpeg and SDL libraries.

  It already can play YUV format video which is directed load into memory and copy into YUVOverlay buffer (it’s very easy).

  Now, I want to use ffmpeg to decode video, but when I call the function avformat_open_input it returns -5 when input is URL string, such as rtmp:// or mmsh:// ; it returns -1052488119 when input is file name, such as /saved/tmp (I mount the file system - html5fs).

  ---

  There are some questions :

  1. What means of -5 and -1052488119 ?
  2. If file can’t open by avformat_open_input, is it possible the input type is from buffer not from file name or url string ?

  ---

  If I’m not clearly about my question or description, you can tell me.
  If you are doing the same thing or having the same problem, we can discuss together.

  Thanks,
  Jar