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• How to optimize video to animated GIF conversion using PHP + shell commands

  15 mars 2012, par user1070798

  I have a web application that converts any video into an animated GIF. The app runs in PHP and the following steps are executed through php's shell_exec :

  1. Scale video to smaller dimensions, if they are large (ffmpeg -i $in -s 200x150 -an $out)
  2. Use ffmpeg to extract 1 jpeg every x seconds (ffmpeg -i $in -ss $ss -vframes 1 $out)

  3. Convert jpegs to animated GIF using imagick (convert -delay $delay -loop 0 $dir/* $out)

     aside - the reason I don't use the ffmpeg gif89a output is because the quality sucks.

  I want to be able to except any major image format, but the most common will probably be .flv (flash) and .avi/.mpg.

  My application runs fine, but I am a perfectionist and it needs to be faster for scalability.

  My web server has 16 cores and I would like to utilize them as much as possible, but .flv multi-threading appears to not be supported by ffmpeg, while .avi and some others are supported. Also, ffmpeg doesn't support multi-threading when outputting to jpegs.

  Does anyone know of any other programs that support multi-threading for .flv and others ? Are there any more efficient methods to create an animated GIF from video, while maintaining relatively decent quality (aka not the 100-color palette that ffmpeg supports) ?

  Also, if anyone knows which codecs might perform best for stages 1 and 2, particularly with flv, I'd love to know. I've done hours of testing, but there are just so many options I haven't come to any solid conclusions.

  ***Update : My online app is working well so far animated gif generator. I would still love to make it faster though, so if anyone has run into similar circumstances... let me know !

• how to make videothumbnail from the middle of the video ?

  28 décembre 2019, par Shahrzad Nazemi

  I am using ffmpeg as my module in Node js app for making video thumbnails.the thing is , it makes it from the beginning of the Video. and some of them begins with a black frame so the thumbnail will be a black picture.I want to know how should I make it from the middle of the video so that they wont be black anymore.
  here is what I did :

  module.exports.createVideoThumbnail = function (path, destination, fileName, cb) 
  
  {
  
      try 
  
      {
  
          var process = new ffmpeg(path);
  
          process.then(function (video) {
  
              video.fnExtractFrameToJPG(destination, {
  
                  frame_rate: 1,
  
                  number: 1,
  
                  start_time: 20,
  
                  duration_time: 1,
  
                  file_name: `${fileName}`
  
              }, function (error, files) {
  
                  if (!error) 
  
                  {
  
                      console.log('Frames: ');
  
                      cb(1)
  
                  }
  
                  else 
  
                  { console.log(error); cb(-1); }
  
              });
  
  
  
          }, function (err) {
  
              console.log('Error: ' + err);
  
              cb(-1)
  
          });
  
      } 
  
      catch (e) 
  
      {
  
          console.log(e.code);
  
          console.log(e.msg);
  
          cb(-1)
  
      }
  
  }

• ffmpeg how to crop and scale at the same time ?

  13 décembre 2018, par Mitchell Faas

  I’m trying to convert a video with black bars, to one without and if the source is 4k, I want the video to be converted to 1080p

  Now to do this, I’m using the following command :*

  ffmpeg -i input ... -filter:v "crop=..." -filter:V "scale=1920:-1" ouput

  But running this, I found that the end product still has said black bars and is 1920x1080 as opposed to the 1920x800 I’d expect.

  What gives, why does this not work ?

  * : Other settings have been left out for convenience.