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• "Format" or style the output of showwaves/showwavespic in ffmpeg

  9 avril 2020, par flomei

  I'm trying to get my head wrapped around ffmpeg and its functions and filters.

  



  showwaves and showwavespic already create nice output, but I'm looking to style it even more. Lots of audioplayers for example create a "waveform" like the following, which would be a job for showwavespic, I think. (I think soundcloud for example does create a form like this with actual data.)


  



  I wonder if I can use ffmpeg to create something like this directly from my raw input data. I thought I might need to split my audio track into X parts, calculate the average distance from the Y-axis and then create a bar. But I'm not sure if I can manage to do that with ffmpeg or if I need to build more of a toolchain for that.

  



  If I could create the output of showwaves to look like that above, that would be great. On the other hand I'd already be happy if I could just increase the stroke width of the showwaves output.

  



  Didn't found anything about the in the documentation or I looked at the wrong places, because I don't yet get the big picture of ffmpeg.

  


• 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.