FFMPEG - Removing audio

To remove all audio stream from an video file, you can us the following

 ffmpeg -i $input_file -c copy -an $output_file

where

-c[:stream_specifier] codec (input/output,per-stream)

-codec[:stream_specifier] codec (input/output,per-stream)

mean

Select an encoder (when used before an output file) or a decoder (when used before an input file) for one or more streams. codec is the name of a decoder/encoder or a special value copy (output only) to indicate that the stream is not to be re-encoded.

copy mean

a parameter for copying stream

-an (input/output) mean

As an input option, blocks all audio streams of a file from being filtered or being automatically selected or mapped for any output. See -discard option to disable streams individually.

As an output option, disables audio recording i.e. automatic selection or mapping of any audio stream. For full manual control see the -map option.

See FFMPEG Audio Options