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• why jmf can't play rtp stream ?

  24 janvier 2017, par ahmet burak

  I produced an rtp link with ffmpeg and I tried to listen and play this stream. VLC and ffmpeg can play rtp stream, both work well but jmf doesn’t.

  Although there is no any error, jmf doesn’t play rtp stream and there is no sound.

  My rtp stream (http:.. is a radio link and rtp :... my stream)

  ffmpeg -i http://airspectrum.cdnstream1.com:8114/1648_128 -acodec copy -f rtp "rtp ://127.0.0.1:10000/audio/1"

  public void play() {
  
      MediaLocator mediaLocator = new MediaLocator("rtp://127.0.0.1:10000/audio/1");
  
      try {
  
          if (mediaLocator == null) {
  
              System.err.println("null locator");
  
          }
  
          player = Manager.createRealizedPlayer(mediaLocator);
  
          player.start();
  
      } catch (CannotRealizeException e) {
  
          e.printStackTrace();
  
      } catch (IOException e) {
  
          e.printStackTrace();
  
      } catch (NoPlayerException e) {
  
          e.printStackTrace();
  
      }
  
  
  
  }

  1. os ubuntu 16.08
  2. java jdk 1.8
  3. javax.media.jmf 2.1.1e (maven repo version)

• Converting videos to flv using ffmpeg

  6 janvier 2012, par user703526

  In my c# application, i am writing code for converting any video format to flv format. For this FFMPEG is used.

  Some times an exceptions is occuring like :

  Attempted to read or write protected memory. This is often an indication that other memory is corrupt

  Below is my code from where the exception throwing,

      IntPtr pFormatContext;
  
      FFmpeg.av_register_all();
  
  
  
      int ret;
  
      ret = FFmpeg.av_open_input_file(out pFormatContext, this.Filename, IntPtr.Zero, 0, IntPtr.Zero);
  
  
  
      if (ret < 0)
  
      {
  
          Trace.WriteLine("couldn't open input file");
  
  
  
          FFmpeg.av_free_static();
  
          return;
  
      }
  
  
  
  
  
      try
  
      {
  
          ret = FFmpeg.av_find_stream_info(pFormatContext);
  
  
  
          if (ret < 0)
  
          {
  
              Trace.WriteLine("couldnt find stream informaion");
  
              FFmpeg.av_close_input_file(pFormatContext);
  
              FFmpeg.av_free_static();
  
              return;
  
          }
  
  
  
  
  
          FFmpeg.AVFormatContext formatContext = (FFmpeg.AVFormatContext)Marshal.PtrToStructure(pFormatContext, typeof(FFmpeg.AVFormatContext));
  
  
  
          Duration = formatContext.duration / FFmpeg.AV_TIME_BASE;
  
  
  
          for (int i = 0; i < formatContext.nb_streams; ++i)
  
          {
  
              FFmpeg.AVStream stream = (FFmpeg.AVStream)Marshal.PtrToStructure(formatContext.streams[i], typeof(FFmpeg.AVStream));
  
              FFmpeg.AVCodecContext codec = (FFmpeg.AVCodecContext)Marshal.PtrToStructure(stream.codec, typeof(FFmpeg.AVCodecContext));
  
  
  
              if (codec.codec_type == FFmpeg.CodecType.CODEC_TYPE_VIDEO)
  
              {
  
                  Height = codec.height;
  
                  Width = codec.width;
  
  
  
                          Type = FileType.flv;
  
                          MimeType = "video/x-flv";
  
  
  
              }
  
  
  
          }
  
      }
  
      catch (Exception ex)
  
      {
  
          Trace.WriteLine("FFMpeg failed to understand the file");
  
      }
  
  
  
      FFmpeg.av_close_input_file(pFormatContext);
  
      FFmpeg.av_free_static();
  
  }

  And from the above code this ret = FFmpeg.av_find_stream_info(pFormatContext); line throws memory corrupt exception.
  Please help me to solve this issue.

• Gnuplot how to set a variable to standard-input if not passed

  27 août 2020, par DDS

  I have a gnuplot script (plot.script) that is invoked like

  


  C:> ffmpeg -i '.\my_awesome_audio_file.wav' -filter_complex aformat=channel_layouts=mono -acodec pcm_s16le -ar 4000 -f data - | gnuplot -e "fileout='plot';fileformat='png';wid=500;" .\plot.script        


  


  Now I'd want to default filein variable to stdin if it is not passed as argument. This because I want to be able to call this script as a 1-liner command with ffmpeg data generation and also as step-by-step procedure

  


  My idea was to use

  


  if(!exists('filein')){
filein = '-';
}


  


  but this throws warning: Skipping data file with no valid points

  


  if i print the variable datafile I got - (I expected something like stdin).

  


  this is the plot.script script :

  


  
if(!exists('filein')){
    filein = '-';
    }

if (!exists("hei")){
    hei = 4444;
    }
if (!exists("wid")){
    wid = 5555;
    }
if(!exists("fileformat")){
     fileformat = 'png';
     }
if(!exists("fileout")){
     fileout = 'risultato';
   }
   
fileout = fileout . '.' . fileformat;
   
if(!exists("dataformat")){
    dataformat = '%int16';
    }
if(fileformat eq 'png'){
  set terminal png transparent size larghezza,altezza;
  
  }else{
  set terminal fileformat size wid,hei;
  }
  set output fileout;
  unset key;
  unset tics;
  unset border;
  set lmargin 0;
  set rmargin 0;
  set tmargin 0;
  set bmargin 0;


print filein;
plot filein binary filetype=bin format=dataformat endian=little array=1:0 with lines linecolor "0x009900";


  


  But I also want to call this command-by-command :
generate the data-file :

  


  c:> ffmpeg -i '.\my_awesome_audio_file.wav' -filter_complex aformat=channel_layouts=mono -acodec pcm_s16le -ar 4000 -f data audio.dat


  


  plot the data :

  


  c:> gnuplot -e "filein='audio.dat';fileout='plot';fileformat='png';wid=500;" .\plot.script