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I am trying to get the following screencast command to work:

avconv -f alsa -ar 44100 -ac 2 -i default -acodec aac -strict experimental -ab 320k -f x11grab -s 1024x600 -r 24  -i :0.0  -vcodec rawvideo screencast.mp4

But I still get the following error:

encoder 'aac' is experimental and might produce bad results. Add '-strict experimental' if you want to use it

Other sites suggest making sure that the -strict experimental appears immediately after the aac parameter, which I have done, to no effect.

Nicholas
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1 Answers1

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Move both the -acodec aac and -strict experimental to somewhere after the last -i parameter in the command line, before the output file name.

Parameters to avconv are parsed as "avconv [input1 options] -i input1 [input2 options] -i input2 [output options] outputfile", so when you added these parameters before the second -i they were interpreted as options to the second input, not to the output.

mstorsjo
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    let me rephrase: `-strict experimental` should be on the output, because the encoder is experimental; the aac decoder isn't, so don't use it for aac inputs – guillaume May 13 '16 at 07:49