I'm having major issues combining/merging(lossless) swf video files into a single file then converting to something more useful(mp4).

I've tried using premiere but no audio as it doesn't import the audio. I have many of these files(hundreds) and need a simple way to merge them and convert. I don't really want to convert these files then merge then convert as they are already low quality and they don't need any more artifacts.

  • to me it sounds like a codec problem.
    – blindfold
    Jan 24, 2012 at 9:50

3 Answers 3


One possible solution is: SQUARED 5 MPEG STREAMCLIP it's a freeware converter with basic editing functions. The Batch function should help you.

Other possible software solution: AviDemux

  • 1
    I'm using WinFF to first convert to mpg then copy /b to combine and streamclip to fix the timebreaks. With WinFF I just have to drag and drop all the swf files and let it go(i.e., batch). Only one that seems to properly convert the swf files.
    – Uiy
    Jan 28, 2012 at 10:05

The first thing you need to accomplish is to extract the video from the SWF. A SWF is not a video file. It is an application or small program. There is an "FLV video" compiled into it. Try SWF Decompiler. It might be able to extract the FLV from the SWF.

Once you have the FLV (the actual video file), there are numerous video editors that can read and edit it.


'Hundreds of files' sounds like you could go for automation, rather than a heavy GUI-based solution like a proper NLE. The command-line tool ffmpeg has an option you may find useful: the concat demuxer. To concatenate files with the same resolution, first create a file called inputs.txt, containing lines like:

file 'input1.swf'
file 'input2.swf'
file 'input3.swf'

One file per line. Then, using ffmpeg:

ffmpeg -f concat -i inputs.txt \
-c:v libx264 -crf 22 -preset veryfast \
-c:a libfdk_aac -q:a 3 output.mp4

For more information on the encoding options, look here and here.

For other concatenation options with ffmpeg, see here.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.