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• ffmpeg decode one video frame at a time

  28 juillet 2014, par Krishna

  Most ffmpeg examples online show video decoding using a while () and the entire sequence is decoded in one attempt. For example,

  while(av_read_frame(pFormatCtx, &packet)>=0) {
  
      if(packet.stream_index==videoStream) {
  
  
  
          // Decode video frame
  
          avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
  
                       packet.data, packet.size);
  
  
  
          // Did we get a video frame?
  
          if(frameFinished) {
  
               ... do something   
  
          }
  
       } 
  
  
  
    // Free the packet that was allocated by av_read_frame
  
    av_free_packet(&packet);
  
  }

  Is there a technique to (1) create a function that will decode only one frame and (2) then call that function repeatedly (how many ever times needed).

  I wrote such a function and tried to decode an HEVC stream and I always get this error "Could not find ref with POC xx", where xx stands for some integer. Looks like it can’t find references — how do I get around this ?

  Thanks !

• How do i create a batch file that iterates through the files in a folder and executes another .bat on them ?

  1er mai 2013, par El Guapo

  i have a folder full of .avi files and i want to use ffmpeg to convert them to .mp4 files. I followed an online tutorial to create a batch file that does just this, here is the code :

  "C:\ffmpeg\ffmpeg.exe" -y -i %1 -sameq -ar 22050 -vcodec libx264 "C:\videos\Series 1\S01E01.mp4"

  This works fine if i just drag and drop the .avi files onto the createmp4.bat file containing the above code. However i want to be a little bit smarter about this and use another batch file that will iterate through the .avi files in the folder and run createmp4.bat on all of them and copy them to the C :\videos\Series 1\ directory.

  I would also like to change the name of the files if possible to S01E01.mp4, S01E02.mp4 and so on if possible.

  Any help on this would be greatly appreciated. Oh and just in case you hadn't guessed i am fairly clueless about writing batch files !!

  Thanks

• How ffmpeg work on server for different type of users ? [on hold]

  7 août 2016, par sam

  I have a question about ffmpeg and I am using mac and xampp and php and jQuery. I make a function that upload video or image file or another type when I saw examples of ffmpeg in Stack Overflow. My questions are :

  1. client can be window user or mac or another than we have to download all different type of ffmpeg file for example ffmpeg.exe and mac can be another because when I saw how to download ffmpeg than they show me different operating system.

  2. And where we have to save ffmpeg file in xampp

  3. If I download all things for mac and I run it and it works and I make my website online and than any Windows user or Linux user will upload video it will work for him also. But we do not client download ffmpeg in their system

  If anybody know good example of create thumbnail for video please tell me.