函数 av_channel_layout_describe_bprint 

pub unsafe extern "C" fn av_channel_layout_describe_bprint(
    channel_layout: *const AVChannelLayout,
    bp: *mut AVBPrint,
) -> c_int

bprint variant of av_channel_layout_describe().

@note the string will be appended to the bprint buffer. @return 0 on success, or a negative AVERROR value on failure.