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Yesterday I installed the latest Kubuntu release 14.04. So I meet a little problems with the media conversions. The old FFmpeg is finally replaced with avconv which is in the libav-tools library. Till now i was using ffmpeg and every mp4 or flv to mp3 conversion was very fast. For example if one file around 5mins length was converted for ~20secs, now the same file is converted ~3-4-5 times slower. I read everywhere, but could not find where is the problem.. Is there any cure about that?

Best regards :)

m1nev
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2 Answers2

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So the answer is in one simple parameter -vn which disable video recording for the output which is actually unneeded when making conversion from mp4(probably every video file) to mp3.

‘-vn (output)’ Disable video recording.

In my case I'm using Download Helper for Firefox. I made custom mp3 conversion where added this parameter there and now everything is even faster than ffmpeg.

m1nev
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It would be well worth experimenting a little with the avconv -threads option. For example when transcoding from mp4 to mp3 file, as you mentioned, try something like the following:

avconv -i input.mp4 -threads auto -vn -c:a libmp3lame -qscale:a 3 output.mp3

The -threads option also accepts an integer so you could experiment a little with this. If this makes no difference the eventual answer is probably that your copy of FFmpeg encodes faster than your copy of avconv. Try using the time utility to quantify the difference...

andrew.46
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