util/pixel_format: add PixelFormat

src/util/mod.rs

@@ -5,6 +5,7 @@ pub mod media;
 pub mod color_space;
 pub mod color_range;
 pub mod sample_format;
+pub mod pixel_format;
 
 use std::ffi::CStr;
 use std::str::from_utf8_unchecked;