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• libx264 performances on iOS

  8 mai 2012, par Gilad

  I was wondering whether someone has some experience using libx264 on iPhone.

  How does it perform ? What framerate can I expect ? Will it work for simultaneous encoding & decoding (video call) or the CPU can't handle it ? I'm mainly interested with iPhone 4 and above (iPhone4/iPad 2)

  Are there any precompiled universal binaries I can use ?

• apply ffmpeg to many files

  30 juillet 2015, par puchu

  I have written simple script :

  #!/bin/bash
  
  find . -name "*.m4a" | while read filename;
  
  do
  
      new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
  
      if [ ! -f "$new_filename" ]
  
      then
  
              #ffmpeg -i "$filename" -acodec flac "$new_filename" > /dev/null 2>&1;
  
              #wait $!;
  
              echo "$filename";
  
              echo "$new_filename";
  
      fi
  
  done

  it outputs correct result :

  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

  if uncomment ffmpeg and wait :

  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
  
  ./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
  
  uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
  
  uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

  And no flacs has been done !

  PS

  #!/bin/bash
  
  find . -name "*.m4a" | while read filename;
  
  do
  
      new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
  
      if [ ! -f "$new_filename" ]
  
      then
  
              ffmpeg -i "$filename" -acodec flac "$new_filename";
  
              echo "$filename";
  
              echo "$new_filename";
  
      fi
  
      sleep 5;
  
  done

  1) encode start but suddenly stop with no error messages

  2) encode couldn’t start because of "uilibrium" instead of "./Equilibrium"

  3) = 1)

  4) = 2)

  ...

  last) correctly

• How to optimize FFMPEG with pipe and memory reuse in Tide SDK

  7 janvier 2014, par Vincent Duprez

  Im running into an speed optimization issue. Im building a video cut tool in web technologies on desktop with TideSDK. On of the tools has a timeline with a position slider

  basically, whenever the slider moves, (using jquery UI), I get the position, translate this into a timecode and asks FFMPEG to encode to a file, when a get the finished event, I simply update the background-image attribute of the 'viewer' to this file. The file is located in some temporary folder.

  The thing is, it is just a bit too slow. Usable, but slow (approx 2 fps on a High end Computer)
  I think there are 2 bottlenecks on this strategy :
   Writing ffmpeg output to a file & reading back in css
   repeatedly loading the same movie file in ffmpeg

  This is the code executed on each move (var timecode is the calculated timecode based on the pointer position)

  var cmd = [FFMPEG];
  
  cmd.push('-y'); //overwrite existing files
  
  cmd.push('-ss',timecode); //CUE position
  
  cmd.push('-i',input); //input file
  
  cmd.push('-f','image2'); //output format
  
  cmd.push('-vframes','1'); //number of images to render
  
  cmd.push(Ti.API.Application.getDataPath( )+"/encoderframe.jpg"); //output file
  
  
  
  var makeframe = Ti.Process.createProcess(cmd);
  
  makeframe.setOnReadLine(function(data){ /*console.log(data);*/ });
  
  var time = new Date().getTime();
  
  makeframe.setOnExit(function(){ ffmpegrunning = false;  $('#videoframe').css('background-image','url(file://'+Ti.API.Application.getDataPath( ).replace(" ","%20")+'/encoderframe.jpg?'+time+')');     });
  
  makeframe.launch();

  Basically, this repeatedly asks the same Command :

  ffmpeg -y -ss 00:00:01.04 -i /somepath/somevideo.mov -f image2 -vframes 1 /path/to/output/encoderframe204.jpg

  How can I optimize this code, Pipe to output straight to css background with Base64 data, or reuse loaded memory file in ffmpeg. ?

  Thanks !