函数 av_dv_frame_profile 

pub unsafe extern "C" fn av_dv_frame_profile(
    sys: *const AVDVProfile,
    frame: *const u8,
    buf_size: c_uint,
) -> *const AVDVProfile

Get a DV profile for the provided compressed frame.

@param sys the profile used for the previous frame, may be NULL @param frame the compressed data buffer @param buf_size size of the buffer in bytes @return the DV profile for the supplied data or NULL on failure