pub unsafe fn alloc_set_opts2(
_out_ch_layout: *const AVChannelLayout,
_out_sample_fmt: AVSampleFormat,
_out_sample_rate: c_int,
_in_ch_layout: *const AVChannelLayout,
_in_sample_fmt: AVSampleFormat,
_in_sample_rate: c_int,
) -> Result<*mut SwrContext, c_int>