FFmpeg 1.2.12
Since* 0.11
#

Mixes multiple audio inputs into a single output.

For example

ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT

will mix 3 input audio streams to a single output with the same duration as the first input and a dropout transition time of 3 seconds.

The filter accepts the following named parameters:

inputs

Number of inputs. If unspecified, it defaults to 2.

duration

How to determine the end-of-stream.

longest

Duration of longest input. (default)

shortest

Duration of shortest input.

first

Duration of first input.

dropout_transition

Transition time, in seconds, for volume renormalization when an input stream ends. The default value is 2 seconds.