[FFmpeg-user] Ffmpeg Simple Command line Question

[Moritz Barsnick]

On Fri, Feb 13, 2015 at 18:55:53 +0100, Szabolcs Illés wrote:

> I just want to join two mp3 files together but some of the files
> speed would be different and create an other file called result mp3.

That is a very confusing text.

Assuming you want to concatenate the two audio files (i.e. add their
content after one another), you should look at the concat filter:
https://trac.ffmpeg.org/wiki/Concatenate#filter
and add the atempo filter to the filter chain (atempo=0.5):
https://ffmpeg.org/ffmpeg-filters.html#atempo

Cheers,
Moritz