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• Optimize ffmpeg 2 pass command to speed up compression

  21 août 2022, par Khawar Raza

  In my android app, I am using ffmpeg wrapper library ffmpeg-kit. User is offered different file sizes and video file is compressed to the selected file size. I am using ffmpeg 2 pass command technique to compress video file to desired size. Here are the commands :

  


   -y -i "input.mp4" -c:v h264 -b:v 8064k -s 1920x1440 -pass 1 -an -f mp4 -passlogfile "logfile.passlogfile" /dev/null

 -i "input.mp4" -c:v h264 -b:v 8064k -s 1920x1440 -pass 2 -c:a aac -b:a 128k -passlogfile "logfile.passlogfile" "outfile.mp4"


  


  Here file size 8064k and resolution 1920x1440 are dynamically set. It works for small video files but takes considerably high amount of time for large videos to finish the job. Can we optimize this process to complete it in less time ?

  


  Note : The whole purpose of this process is to compress video to a desired file size where video quality will surely be compromised.

  


• How to detect a common section in a set of videos with ffmpeg [on hold]

  7 août 2019, par Hans J

  I have a set of videos that are assumed to contain common (or very similar) sections. I want to be able to detect (with FFmpeg) how long each common section is, and where the sections are in each individual video.

  An individual section can have multiple scene changes, and is continuous. A common section would also be assumed to be longer than 10 seconds (This is an arbitrary choice, it can be changed).

  The final output of the command would include the various time-codes of the instance of each section in each video. Assuming a timebase 1/1, with 1 common section that is 60 seconds long, an output would along the lines of :

  Video1.mp4 0 60
  
  Video2.mp4 120 180
  
  Video3.mp4 50 110
  
  Video4.mp4 null

  where video1, video2, video3, and video4 are the input videos. In this case, video4 does not contain a common section.

  For example, I could have three episodes of a TV show. They all contain the same commercial. Without knowing what that commercial is, I want to be able to find where that commercial shows up in each of the episodes. Ideally the function would detect additional common commercials as well.

  Edit : Another example would be removing the intro sequence in all three episodes.

  Note : For the purpose of a good solution, the common sections do not have to exactly match. Because there could be artifacts or embedded subtitles in one episode and not the other.

• Separating webserver and processing server

  6 mars 2020, par John Doe

  I would like an architecture design advice.

  I have a projet composed of a public Node.JS API server (handling client HTTP browser requests)

  The purpose of my project is to convert an image to a video (I do this using ffmpeg as CLI and it can take some time)

  The business workflow should be the the following :

  1) A user sends an image URL and his email (as POST parameters) to the API

  2) The API should responds "OK 200" and send later an email containing a video of the image

  Here is my idea (and what my current program does) :

  1) The nodeJS API directly responds "OK 200" to the client

  2) The nodeJS server asynchronously downloads the image using npm axios library, then saves that image to current directory, then asynchronously launchs a heavy tool that convert
  the image to a video (can take some time), then sends an email to the client.

  In my design everything occurs on the same server (NodeJS API).
  I think this isn’t a good design at all and I should separate the Nodejs HTTP API and the heavy tasks video processing server.
  However, this separation means communicating image from a server to another one and i don’t know how to do that.

  I think there are useful services that I could use on AWS but I don’t know which one and how.

  Would it be possible to help me in the design of this application (and which cloud services could I use ?)