Fix empty names

src/codec/codec.rs

@@ -39,7 +39,15 @@ impl Codec {
 	}
 
 	pub fn description(&self) -> &str {
-		unsafe { from_utf8_unchecked(CStr::from_ptr((*self.as_ptr()).long_name).to_bytes()) }
+		unsafe {
+			let long_name = (*self.as_ptr()).long_name;
+			if long_name.is_null() {
+				""
+			}
+			else {
+				from_utf8_unchecked(CStr::from_ptr(long_name).to_bytes())
+			}
+		}
 	}
 
 	pub fn medium(&self) -> media::Type {

src/format/context/input.rs

@@ -2,7 +2,6 @@ use std::{
 	ffi::CString,
 	mem,
 	ops::{Deref, DerefMut},
-	ptr,
 };
 
 use super::{common::Context, destructor};
@@ -199,7 +198,7 @@ pub fn dump(ctx: &Input, index: i32, url: Option<&str>) {
 		av_dump_format(
 			ctx.as_ptr() as *mut _,
 			index,
-			url.map(|u| u.as_ptr()).unwrap_or(ptr::null()),
+			url.unwrap_or_else(|| CString::new("").unwrap()).as_ptr(),
 			0,
 		);
 	}

src/format/context/output.rs

@@ -174,7 +174,7 @@ pub fn dump(ctx: &Output, index: i32, url: Option<&str>) {
 		av_dump_format(
 			ctx.as_ptr() as *mut _,
 			index,
-			url.map(|u| u.as_ptr()).unwrap_or(ptr::null()),
+			url.unwrap_or_else(|| CString::new("").unwrap()).as_ptr(),
 			1,
 		);
 	}