[Stephen Dixon]

ffmpeg -i \path\to\your\movie.avi -vcodec prores -profile hq -acodec pcm_s16be \path\to\your\output\file.mov

easy peasy. The only bit you have to change is the path to your input and output. You can get this easily by typing the ffmpeg -i(space)bit and then dragging the file onto the command prompt window. Or you can change the working directory to the folder that the input file is in and then you’ll only have to type the file name.

To change the working directory do

cd \path\to\the\directory

again, drag the folder after typing cd(space) and it will fill in the path for you.

Also you can use the tab completion function. So if you have a file called test_movie.avi in the current directory you can just type tand hit the tab key, and it will autocomplete (if there are more files that begin with t you can either keep hitting the tab key and it will cycle through all the possibilities, or you can type a bit more of the name to narrow down the choices.

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

You’re asking this on the ffmpeg forum? Like we’re really going to say Mencoder 😉

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

ffmpeg -i inputfile.ext -vn -acodec codecname outputfile.ext

-vn just means no video.

You’ve got to make sure you output format (specified by ext) matches your codec, so if you’re saving with aac you’ll need to save as outputfile.aac or if you’re using WAV you might want pcm_s16be or so on.

The aac codec is not a good one to use. Are you getting messages that tell you to use “-strict experimental” if you want to use it? You could compile with libfaac support (you can see if it’s already supported by doing ffmpeg -version and seeing if it comes up), or you can use libaacplus.

If that doesn’t work, post the commands your using and the results you get.

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

you can use nice if you’re on linux/os x eg:
nice 20 ffmpeg…

This will give it a lower priority (the higher the number the lower priority the process is), but of course if there is nothing else using the CPU it will still take 100% of the available cpu time.

Nice can also be used for evil of course, you can set it to 0 to take high priority, or if you have super user rights set it to -20 to be really un-nice.

Windows users can use the start command
start [/LOW | /NORMAL | /HIGH | /REALTIME | /ABOVENORMAL | /BELOWNORMAL] ffmpeg…

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

Post your command. The default settings for ffmpeg are often very low quality, so unless you specify higher quality / data rate they tend to give you tiny, but shonky looking results.

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

use ffmpeg -v to find out about your ffmpeg instalation. You have to install libx264 separately and specify –enable-libx264 when you compile ffmpeg.

libx264 is available from the videolan folks: https://www.videolan.org/developers/x264.html

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

Why use an AVI then. An MP4 is a much better bet.

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

Typo, sorry. Should have been “libx264”. The “unknown encoder” means that ffmpeg wasn’t compiled with that codec enabled. You can either install that codec and recompile or try using the ffmpeg default mp4 audio encoder (I’m not 100% sure what that is..?). Just don’t specify an audio codec and see what you get in the output.

Arguments can be in any order, but there are restrictions on where they go with respect to the input and output part of the command. You’ll ahve to read the manual for the ins and outs, but usually all the conversion type arguments can be anywhere as long as they’re between the input and the output file specifiers.

Stephen Dixon
Editor, Animator, Motionographer
Museum Victoria

[Stephen Dixon]

You don’t need to pipe it through ffmpeg. What you’re doing wrong is using > instead of >>
The single angle brace overwrites whatever’s already in the file, the double brace appends it to the end. See section 3.6.3 here

[Stephen Dixon]

ffprobe. It comes with ffmpeg, just like ffplay.

ffprobe /[path/to/your/video.mov

For extra laffs you can redirect the stderr to stdout and pipe it to grep and/or sed if you’re using it as part of a larger application, eg:

ffprobe ~/mymovie.mov 2>&1 |grep Duration|sed "s/[A-z :]*\([0-9:.]*\).*/\1/"
00:00:50.66

The sed example above uses OSX’s curious sed implementation, you may not need to escape the brackets.