title: Video Slideshow from png files + mp3 audio
body: <p>I have a bunch of .png frames and a .mp3 audio file which I would like to convert into a video. Unfortunately, the frames do not correspond to a constant frame rate. For instance, one frame may need to be displayed for 1 second, whereas another may need to be displayed for 3 seconds.</p>
  
  <p>Is there any open-source software (something like ffmpeg) which would help me accomplish this? Any feedback would be greatly appreciated. </p>
  
  <p>Many thanks!</p>