examples/metadata: update to new format API

examples/metadata.rs

@@ -1,9 +1,12 @@
 extern crate ffmpeg;
 
 use std::env;
-use std::path::Path;
 
-fn print_metadata(context: &ffmpeg::format::Context) {
+fn main() {
+	ffmpeg::init().unwrap();
+
+	match ffmpeg::format::input(&env::args().nth(1).expect("missing file")) {
+		Ok(context) => {
 			for (k, v) in context.metadata().iter() {
 				println!("{}: {}", k, v);
 			}
@@ -67,20 +70,10 @@ fn print_metadata(context: &ffmpeg::format::Context) {
 					}
 				}
 			}
-}
 
-fn main() {
-	ffmpeg::init().unwrap();
-
-	if let Some(file) = env::args().nth(1) {
-		let path = Path::new(&file);
-
-		match ffmpeg::format::open_input(&path) {
-			Ok(context) => print_metadata(&context),
-			Err(error)  => println!("error: {}", error),
 		}
-	}
-	else {
-		println!("Usage: metadata <path>")
+
+		Err(error) =>
+			println!("error: {}", error)
 	}
 }