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• ffmpeg - which video rate is correct ?

  7 mai 2014, par mast kalandar

  I am using ubuntu 13.04

  Version of ffmpeg is ffmpeg version N-61041-g52a2138

  Through php, I am calling ffmpeg commands to extract images and do some modification in those images and again merge those images back to video.

  While merging all images through ffmpeg command, I need to pass video bit rates.

  Command is as below

  public function mergeImagesToVideo($frame_no,$user_directory_name,$video_bit_rates,&$output,&$status){
  
          /* merge all of frames to create one second video */
  
  
  
          $user_frames_path=$GLOBALS["all_user_dir_path"].$user_directory_name."/";
  
  
  
          $command= $GLOBALS['ffmpeg'].' -f image2 -r 30 -i '.
  
                    $user_frames_path.'f'.$frame_no.'_%d.png -r 30 -b:v '
  
                    .$video_bit_rates.'k '.$user_frames_path.'f'.$frame_no.'.mp4';
  
  
  
          //echo $command;
  
          exec($command,$output,$status);
  
          return;
  
      }

  The call is made as below

  $this->mergeImagesToVideo($start_second,$user_directory,$video_bit_rates,$output,$status);
  
  
  
                if($status!=0){
  
                  echo "some thing went wrong in merging all images to create a video <br />";
  
                }

  Now When check bit rates through ffmpeg command output is like as below

  ffmpeg -i f1.mp4

  This command shows 7303 kb/s

  

  While I right click the image and show properties, it shows 7295 kbps

  

  Which is the correct one ?? Not getting correct line..

  Thanks in advance.

• ffmpeg command to scale, show images at exactly 130bpm [closed]

  17 août 2023, par S. Imp

  I have a sequence of images which I would like to display to some music that plays at 130bpm. I'll also need to scale the images, which are a rather strange 2673x2151 pixels each down to something, ideally something that would fit without stretching inside a 1080p frame — e.g. 1342x1080.

  


  130BPM yields weirdness with frame rates. There are 2.16666666667 (13/6) beats per second. This being the case, I can't figure out how many frames to show each each image at the usual frame rates (24, 25, 30 fps). If I could make a movie with a frame rate of 2.16666667 frames per second, i could simply show each image for one frame. This seems like it might actually be optimal — it would probably make a a very compact video file, right ??

  


  Alternatively, if we must set the frame rate to an positive integer value, 13 frames per second works if we just display each image for six frames. 13 FPS means 780 frames per minute. 780 frames divided by 130 beats means 6 frames per beat.

  


  Finally, my images are named j1.jpg, j2.jpg, j3.jpg, etc.

  


  Can someone help me concoct an ffmpeg command to assemble these images into a video with each image lasting one beat at 130BPM ? I've been trying to massage this command, which does assemble the images into a movie, but my attempts to specify a frame rate have had weird effects. E.g., doing a -r results in strange videos that change image very erratically. I think it's because there's a setpts=N/25/TB bit in there.

  


  ffmpeg -pattern_type glob -i "j*.jpg" -filter_complex "[0]reverse[r];[0][r]concat,loop=2:250,setpts=N/25/TB,scale=1342:1080" -pix_fmt yuv420p -c:v libx264 -preset slow -b:v 3500k output_looped.mp4


  


  Also, I don't understand what the 250 means in loop=2:250. If someone could explain that to me, I'd be grateful.

  


• Revision 79bd071373 : Merge branch 'indianrunnerduck' * indianrunnerduck : Update CHANGELOG for v1.4

  3 avril 2015, par Johann

  Changed Paths :
   Modify /README

  
  
  Merge branch ’indianrunnerduck’

  * indianrunnerduck :
  Update CHANGELOG for v1.4.0 (Indian Runner Duck) release
  vp9 : fix high-bitdepth NEON build
  Fix use of scaling in joint motion search
  Prepare Release Candidate for libvpx v1.4.0
  vp8cx.h : vpx/vpx_encoder.h -> ./vpx_encoder.h

  Change-Id : Ib2eee50f02e12623aae478871cb9150604bb2ac2