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• How to programmatically start/stop FFMPEG stream transcoding

  3 février 2014, par Paul Wieland

  I have an ip webcam which provides an MJPEG stream. I can successfully transcode and save that stream with ffmpeg under OSX. The following gives me pretty much what I want :

  ffmpeg -f mjpeg -i "http://user:pass@10.0.1.200/nphMotionJpeg?Resolution=640x480&Quality=Standard" -b:v 1500k -vcodec libx264 /tmp/test.mp4

  That will start an FFMPEG session and begin saving the live stream to my test.mp4 file. pressing q will quit ffmpeg and save the file.

  I would like to programmatically start & stop the recording using a PHP or Bash shell script. I have tried the following :

  <?php
  
  
  
  $pid = pcntl_fork();
  
  
  
  if($pid == -1){
  
      die("could not fork"); 
  
  }elseif($pid){
  
      // we are the parent...
  
      print $pid.' started recording. waiting 10 seconds...';
  
      sleep(10); // Wait 10 seconds
  
  
  
      print_r(shell_exec("kill ".$pid)); // Kill the child recording process
  
  
  
      echo 'done';
  
      exit(); 
  
  }else{
  
      // we are the child process. call ffmpeg.
  
      exec('../lib/ffmpeg -f mjpeg -i "http://user:pass@10.0.1.200/nphMotionJpeg?Resolution=640x480&Quality=Standard" -b:v 1500k -vcodec libx264 /tmp/test.mp4');
  
  }

  But there are two problems :

  1. The ffmpeg process does not end/die (probably because its forked again)
  2. When I manually kill the ffmpeg process, the video file is not readable

• Can ffmpeg and libav headers coexist on Ubuntu ? And aren't these headers #includeing each other wrongly ?

  12 mai 2014, par spraff

  So Ubuntu has rejected ffmpeg in favour of its fork libav. I need to develop an app on Ubuntu which uses ffmpeg instead of libav.

  I have compiled and linked ffmpeg separately and it seems to be ok but I’ve just realised I can’t debug it properly because the system headers are for libav.

  I’ve tried putting the ffmepg headers in a local path and doing e.g.

  #include avformat.h>

  instead of

  #include 

  but this gives me errors such as

  ffmpeg-0.8.10/libavformat/avformat.h:455:10: error: use of enum ‘AVCodecID’ without previous declaration

  AVCodecID is defined in avcodec.h but this is included from avformat.h as follows :

  #include "libavcodec/avcodec.h"

  Two questions :

  1. Can I set up the environment so that the local ffmpeg headers include each other correctly, without changing those headers, while libav headers are still installed and on the normal include path ?
  2. Am I crazy or shouldn’t #include "libavcodec/avcodec.h" always fail anyway because it will look for libavformat/libavcodev/avcodec.h which never exists ?

• avcodec/idctdsp : make add/put_pixels_clamped_c internal functions

  13 août 2014, par James Almer

  avcodec/idctdsp : make add/put_pixels_clamped_c internal functions
  This reduces code duplication and differences with the fork.
  Signed-off-by : James Almer <jamrial@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/arm/idctdsp_init_arm.c
  • [DH] libavcodec/idctdsp.c
  • [DH] libavcodec/idctdsp.h
  • [DH] libavcodec/xvididct.c