Convert the input audio format to the specified formats.

The filter accepts a string of the form: "sample_format:channel_layout".

sample_format specifies the sample format, and can be a string or the corresponding numeric value defined in libavutil/samplefmt.h. Use ’p’ suffix for a planar sample format.

channel_layout specifies the channel layout, and can be a string or the corresponding number value defined in libavutil/channel_layout.h.

The special parameter "auto", signifies that the filter will automatically select the output format depending on the output filter.