Function gstreamer_audio_sys::gst_buffer_get_audio_downmix_meta_for_channels

pub unsafe extern "C" fn gst_buffer_get_audio_downmix_meta_for_channels(
    buffer: *mut GstBuffer, 
    to_position: *const GstAudioChannelPosition, 
    to_channels: c_int
) -> *mut GstAudioDownmixMeta