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• Is there a way to get FFprobe to return codec_name from firs first video, audio, and subtitle stream in a video in a single call to FFprobe ?

  26 août 2023, par Chase Westlye

  ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 (filename) 


  


  is how to retrieve the codec_name of the first video stream in a file via FFprobe.

  


  Replace v:0 with a:0 to get the first audio stream, and it returns the codec_name of the first audio stream in the file.

  


  And replace v:0 with s:0 to get the codec_name of the first subtitle stream in the file.

  


  Awesome.

  


  What isn't awesome, is having to call FFprobe three times for these operations and having to hit the file three times.

  


  Is there a way to call FFProbe once, and have FFProbe return the codec_name of the first video, audio, and subtitle stream (instead of separate calls) ?

  


• 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

• 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.