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• sh : ffmpeg : command not found when run command through php

  9 avril 2015, par Ashok

  I have installed successfully installed FFMpeg on root of my Centos 6 machine (https://trac.ffmpeg.org/wiki/CompilationGuide/Centos).

  My workplace of apache/php is /var/www/html

  Now I’m running below command successfully on /var/www/html directory to capture frame from the video file. It’s capturing a frame.

  [root@localhost html]# ffmpeg -i video.mpg -an -ss 30  -t 00:00:01 -r 1 -y -vcodec mjpeg -f mjpeg -s 160x100 frame8  2>&1

  I want to run this command through php and using shell_exec() or exec() php functions. My php code for running the command is :

  $cmd = "/root/bin/ffmpeg -i /project/app/webroot/videos/video.mpg -ss 00:00:14.435 -f image2 -vframes 1 /project/app/webroot/videothumbnails/example-thumb.jpg";
  
  $locale = 'en_IN.UTF-8';
  
  setlocale(LC_ALL, $locale);
  
  putenv('LC_ALL='.$locale);
  
  echo shell_exec($cmd);

  When I’m trying to run command through above php code, I’m getting below error :

  sh: ffmpeg: command not found

  Please help me to solve out this problem.

• Yes or no, will ffmpeg api do hardware decoding on iOS ?

  15 janvier 2019, par Fattie

  There seems to be conflicting information on this.

  https://trac.ffmpeg.org/wiki/HWAccelIntro

  notice the first diagram, it firmly marks iOS as “Y” on VideoToolbox

  

  however in the comments down the bottom it says

  VideoToolbox. ​VideoToolbox, only supported on macOS. H.264 decoding is available in FFmpeg/libavcodec.

  And in the confusing second diagram it says "Standalone" is not done for VideoToolbox.

  We have found that using ffmpeg compiled in to iOS .... it seems to not use hardware decoding, which is really a pain.

  1. With avcodec_get_hw_config() we get AV_PIX_FMT_VIDEOTOOLBOX, AV_HWDEVICE_TYPE_VIDEOTOOLBOX which is seemingly correct.

  2. But usage and framerates clearly shows everything is being done in CPU. The code is in ff_hevc_hls_residual_coding all the time. (That’s fffmpeg’s software decoder.)

  3. This very diff very long git.videolan.org URL here seems to suggest again it should all be working.

  4. Have tried every iPhone etc. of course

• cafenc : fill in avg. packet size later if unknown

  10 juillet 2021, par Roman Beranek

  cafenc : fill in avg. packet size later if unknown
  Frame size of Opus stream was previously presumed here to be 960 samples
  
  (20ms), however sizes of 120, 240, 480, 1920, and 2880 are also allowed.
  
  It can also alter on a per-packet basis and even multiple frames may be
  
  present in a single packet according to the specification, for the sake
  
  of simplicity however, let us assume that this doesn't occur.
  Because the mFramesPerPacket field, representing the number of samples
  
  per packet in the ffmpeg terminilogy, is the key factor in calculating
  
  packet durations and all that follows from that (index, bitrate, ...),
  
  it is crucial to get right.
  Therefore, if the packet size is not available ahead of time (as it is in
  
  the case of Opus), calculate an average from the stream duration once we
  
  know how many packets there are and update the filed in the header.
  

  • [DH] libavformat/cafenc.c