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• Dynamically generate list of arguments for ffmpeg in C

  5 mars 2013, par OregonTrail

  I'm currently writing a video conversion daemon in C. It calls ffmpeg using execvp.

  I've created a struct called "ffmpeg_job" that represents a conversion job to be completed. I'd like to dynamically allocate the arguments to ffmpeg for each job, so that I can free one of these structs and its list of arguments after the job is completed.

  I started writing the function that dynamically allocates the list of arguments, but I feel like the way I'm going about it is quite naive. The code is below.

  Is there a better way to do this ?

  EDIT : I'm thinking now that I will have a static string list of arguments for each level of quality, then sprintf into it and strtok it into a char **

  char ** generate_arguments(
  
      char *filepath,
  
      ph5v_format format,
  
      ph5v_quality quality)
  
  {
  
      char ** arguments;
  
      if (format == ph5v_MP4) {
  
          mp4_arguments = {
  
              "-i", "%%INPUT FILEPATH 1",
  
              "-vcodec", "libx264",
  
              "-preset", "%%X264 PRESET 5",
  
              "-b:v", "%%VIDEO BITRATE 7",
  
              "-strict", "-2",
  
              "-acodec", "aac",
  
              "-b:a", "%%AUDIO BITRATE 13",
  
              "-ar", "%%AUDIO SAMPLERATE 15",
  
              "-ac", "2",
  
              "-y", "%%OUTPUT FILEPATH 19"
  
          }
  
  
  
          arguments = malloc(sizeof(char*) * 20);
  
  
  
          int i;
  
          for (i = 0; i < 20; i++) {
  
              if (i == 1) {
  
                  char *argument = malloc(strlen(filepath) + 1);
  
                  strcpy(argument, filepath);
  
                  arguments[1] = argument;
  
              } else if (i == 5) {
  
                  if (quality == ph5v_LOW || quality == ph5v_MEDIUM) {
  
                      char *argument = malloc(strlen("fast") + 1);
  
                      strcpy(argument, "fast");
  
                      arguments[5] = argument;
  
                  } else if (quality == ph5v_HIGH || quality == ph5v_ULTRA ) {
  
                      char *argument = malloc(strlen("medium") + 1);
  
                      strcpy(argument, "medium");
  
                      arguments[5] = argument;
  
                  }
  
              } else if (i == 7) {
  
                  if (quality ==
  
              .
  
              .
  
              .

• Setting up a server to redistribute a webcam stream

  22 janvier 2013, par Martin Taleski

  I am trying to set up a streaming server that will receive a RTP stream and redistribute it.

  I am able to create the stream with :

  ffmpeg -f video4linux2 -i /dev/video0 -vcodec mpeg2video -r 25 -pix_fmt yuv420p -me_method epzs -b 2600k -bt 256k -f rtp rtp://myserver:8090/

  I see the UDP packets coming to my server, but I was not able to set up a feed and a stream with ffserver. I can also view the stream though VLC if I change the destination IP of the server with my local IP.

  I am now considering writing a daemon in python or perl or C, that will read the UDP packets coming on port 8090 on the server, and distribute them on another port. Not sure if this is a great idea, but can not find any other clues...

  Any clues how to make this happen ?

• avcodec/h264_slice : Check picture structure before setting the related fields

  7 février 2015, par Michael Niedermayer

  avcodec/h264_slice : Check picture structure before setting the related fields
  This might fix a hypothetical race condition
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/h264_slice.c