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• add padding to ffmpeg slideshow images with different dimensions

  3 mars 2023, par Martin

  I have an ffmpeg command which takes 3 audio files and 3 image files, and concats the 3 audio files into a video with length 870.04 seconds, where the images play in a slideshow where each image is shown for 290.015 seconds.

  


  You can copy and paste the command into your web browser search bar to turn it into one line, then run it (filepaths are formatted for win10 command prompt)

  


  ffmpeg 
-r 2 -i "E:\myFolder\10. Deejay Punk-Roc - Knock 'em All The Way Out.aiff"
-r 2 -i "E:\myFolder\11. Deejay Punk-Roc - Spring Break.aiff"
-r 2 -i "E:\myFolder\12. Deejay Punk-Roc - Fat Gold Chain.aiff"
-r 2 -i "E:\myFolder\1_front.jpg"
-r 2 -i "E:\myFolder\2_back.jpg"
-r 2 -i "E:\myFolder\3_cd.jpg"

-filter_complex "[0:a][1:a][2:a]concat=n=3:v=0:a=1[a];[3:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v3];[4:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v4];[5:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v5];[v3][v4][v5]concat=n=3:v=1:a=0,pad=ceil(iw/2)*2:ceil(ih/2)*2[v]"

-map "[v]" -map "[a]" -c:a pcm_s32le -c:v libx264 -bufsize 3M -crf 18 -pix_fmt yuv420p -tune stillimage -t 870.04 

"E:\myFolder\newOutputVid.mkv" 


  


  The most complex part of this command, which is the logic behind how long to show each image, is the filter_complex argument, which I will try to explain below :

  


  -filter_complex "

//concat the three audio files. [0:a] is referring to the 0'th file input which is audio file 'Knock 'em All The Way Out'
[0:a][1:a][2:a]concat=n=3:v=0:a=1[a];

//file input 3, is the first image, 
[3:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v3];[4:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v4];[5:v]scale=w=600:h=593,setsar=1,loop=580.03:580.03[v5];

//concat the three images in order
//set output resolution
[v3][v4][v5]concat=n=3:v=1:a=0,pad=ceil(iw/2)*2:ceil(ih/2)*2[v]"


  


  With the output video that gets rendered, the first image is shown correctly, because the video resolution 600w x 593h is the same as the image itself


  


  The second image however, was stretched to fit the frame of the video.


  


  How can i edit my filter_complex line for the [4:v], the 4th input file which is the second image 2_back.jpg, so that the image is not stretched ? Maybe like add black background padding to keep the image fully visible with the frame and not cropped/stretched

  


  Download files :
http://www.mediafire.com/folder/e8ja1n8elszk1lu,dxw4vglrz7polyh,ojjx6kcqruksv5r,lah9rano4svj46o,q5jg0083vbj9y1p,d3pt8ydf3ulqm5m/shared

  


• What are the gotchas of using statically linked libraries in serverless platforms such as Google Cloud Functions ?

  5 septembre 2017, par Dzh

  Libraries such as ffmpeg-static upload statically linked binaries onto container.

  I wonder what are the drawbacks of using this approach ?

  Does the library size counts against your memory use (it’s billed by GCloud) ?

  Does it slow down the container ? Perhaps some future-proofing issues ?

  Edit : Found something of a related (I wanted to setup OpenCV) on AWS blog. It doesn’t explain drawbacks, just shows how to do it exactly.

• Possible bug in latest google chrome (v62) ?

  21 novembre 2017, par Jalal El-Shaer

  The following demo was working perfectly :

  http://jsfiddle.net/r6wz0nz6/2/

  The following is a sample of ’video-preview’ class in action :

  <a href="https://www.youtube.com/watch?v=v1uyQZNg2vE" target="_blank" class="video-preview" data-frames="100" data-source="http://i.imgur.com/BX0pV4J.jpg">
  
  </a>

  Now, if you use your mouse to scroll from left-to-right, somehow it is not working (shows thumbnail instead of current image position). This was working perfectly before v62. While, from right-to-left, it works normally.

  Updated Please watch how this looks here : https://www.youtube.com/watch?v=HvDP-YXJgOk

  Question : How can I overcome this bug/issue ?

  P.S. the demo is based on this blog post (https://www.binpress.com/tutorial/how-to-generate-video-previews-with-ffmpeg/138)

  Update 2
  Interesting, in the following part :

  elm.mousemove(function(e) {
  
  var left = e.clientX - elm.position().left;
  
  slider.show().css('left', left -1); // <<---------------------- this line
  
  img.css('left', -Math.floor((left / width) * frames) * width);

  if I remove the ’-1’ like so :
  slider.show().css('left', left);
  It works from Left-To-Right, but now from Right-To-Left is showing same bug !!

  Proposed Workaround by @A. Wollf
  Change the "mouseout" to "mouseleave" and it seems to fix it : http://jsfiddle.net/r6wz0nz6/388