Since*
0.10
Split input audio into several identical outputs.
The filter accepts a single parameter which specifies the number of outputs. If unspecified, it defaults to 2.
For example:
[in] asplit [out0][out1]
will create two separate outputs from the same input.
To create 3 or more outputs, you need to specify the number of outputs, like in:
[in] asplit=3 [out0][out1][out2]
ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
will create 5 copies of the input audio.