[FFmpeg-user] demuxing and re-muxing of mxf video files

Rodney Baker rodney.baker at iinet.net.au
Fri Apr 22 13:42:01 CEST 2011

On Fri, 22 Apr 2011 16:56:12 Paul Tapper wrote:
> Hi,
> I hope this is the right place to post this question.  Sorry if it isn't.
> I'm trying to use FFmpeg to take an .mxf file and:1. demux the audio out of
> it to a .wav (and then process the .wav myself), then2. mux together the
> video from the original .mxf with the .wav that I have now processed, to
> get back to an .mxf file, as similar as possible to the original .mxf, but
> now with my processed audio, instead of the original audio. I've got step
> 1. working with a very simple:
> ffmpeg.exe -i "test.mxf" "test.mxf.wav"
> but I'm a bit stuck on step 2.
> I've tried the following:
> ffmpeg.exe -an -i "test.mxf" -i "test.mxf.wav" -vcodec copy
> "test.mxf.remux.mxf" but I get an error "[mxf @ 01EF8610] track 0: could
> not find essence container ul, codec not currently supported in container"
> Please could anyone suggest what I should do here?  Is this even a
> sensible thing to attempt with FFmpeg? Thanks
> Paul

First of all, you're telling ffmpeg that you want no audio (the -an) switch, 
then trying to add audio.

You need to specify the 2 input files as you have done, but then map the 
streams from each input file to the output file. If the video in test.mxf is 
stream 0 then you would use -map 0:0 -map 1:0.

You also need the "newaudio" switch.

Your final command would look something like:

ffmpeg -i test.mxf -i test.mxf.wav -acodec copy -vcodec copy -map 0:0 -map 1:0 
output.mxf -newaudio

You might have to play around with the order of the options (order is 
important). Others who have done this before may have better suggestions. 

Rodney Baker VK5ZTV
rodney.baker at iinet.net.au

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