Recherche avancée

Sur d’autres sites (7069)

• Scene detection and concat makes my video longer (FFMPEG)

  12 avril 2019, par araujo

  I’m encoding videos by scenes. At this moment I got two solutions in order to do so. The first one is using a Python application which gives me a list of frames that represent scenes. Like this :

  285
  
  378
  
  553
  
  1145
  
  ...

  The first scene begins from the frame 1 to 285, the second from 285 to 378 and so on. So, I made a bash script which encodes all this scenes. Basically what it does is to take the current and previous frames, then convert them to time and finally run the ffmpeg command :

  begin=$(awk 'BEGIN{ print "'$previous'"/"'24'" }') 
  
  end=$(awk 'BEGIN{ print "'$current'"/"'24'" }') 
  
  time=$(awk 'BEGIN{ print "'$end'"-"'$begin'" }') 
  
  
  
  ffmpeg -i $video -r 24 -c:v libx265  -f mp4 -c:a aac -strict experimental -b:v 1.5M -ss $begin -t $time "output$count.mp4" -nostdin

  This works perfect. The second method is using ffmpeg itself. I run this commands and gives me a list of times. Like this :

  15.75
  
  23.0417
  
  56.0833
  
  71.2917
  
  ...

  Again I made a bash script that encodes all these times. In this case I don’t have to convert to times because what I got are times :

  time=$(awk 'BEGIN{ print "'$current'"-"'$previous'" }') 
  
  ffmpeg -i $video -r 24 -c:v libx265  -f mp4 -c:a aac -strict experimental -b:v 1.5M -ss $previous -t $time "output$count.mp4" -nostdin

  After all this explained it comes the problem. Once all the scenes are encoded I need to concat them and for that what I do is to create a list with the video names and then run the ffmpeg command.

  list.txt

  file 'output1.mp4'
  
  file 'output2.mp4'
  
  file 'output3.mp4'
  
  file 'output4.mp4'

  command :

  ffmpeg -f concat -i list.txt -c copy big_buck_bunny.mp4

  The problem is that the "concated" video is longer than the original by 2.11 seconds. The original one lasts 596.45 seconds and the encoded lasts 598.56. I added up every video duration and I got 598.56. So, I think the problem is in the encoding process. Both videos have the same frames number. My goal is to get metrics about the encoding process, when I run VQMT to get the PSNR and SSIM I get weird results, I think is for this problem.

  By the way, I’m using the big_buck_bunny video.

• How to build a xcode project of ffmpeg

  23 avril 2012, par seanxiaoxiao

  Nowadays I had encountered several problems on building a ffmpeg lib for my ios application.

  I was thinking that I should be best to make up a subproject of the ffmpeg lib for this application.

  Just like the project http://wunderradio.com/code.html, it had a subproject of ffmpeg, but it cannot be applied to my project because it does not contain the code of the mp3 decoder.

  Does anyone know how to build a project in xcode4.3 or is there any sample of the project.

  Thanks

• Make 2 videos on top of each other in a 1080×1920 scene

  6 octobre 2023, par Byte me

  I am trying to make two videos on top of each other. Right now i am scaling both to 1080x960 using ffmpeg and putting them together using vstack. Unfortunetely no success. Can anyone help me ?

  


    ffmpeg()
      .input('./placeholder.mp4').videoCodec('copy')
      .input("./scaled_YT.mp4").videoCodec('copy')
      .complexFilter([
        `[0:v]scale=1080x960[v0];[1:v]scale=1080x960[v1];[v0][v1]vstack=inputs=2[v]`
    ], ['v'])
      .toFormat('mp4')
      .on('end', () => {
          console.log('Files have been merged!');
      })
      .on('error', (err) => {
          console.error('Error:', err)
      })
      .save(outputPath);


  


  Error: Error: ffmpeg exited with code 1: &#xA;    at ChildProcess.<anonymous> (D:\Discord Bots\TEMP_TEST\done_projects\videoEditor_bot\node_modules\fluent-ffmpeg\lib\processor.js:182:22)  &#xA;    at ChildProcess.emit (node:events:513:28)&#xA;    at ChildProcess._handle.onexit (node:internal/child_process:291:12)&#xA;</anonymous>