codec/packet: add rescale_ts() method

src/codec/packet/mod.rs

@@ -9,7 +9,7 @@ use std::mem;
 
 use libc::c_int;
 use ffi::*;
-use ::{Error, format};
+use ::{Error, Rational, format};
 
 pub struct Packet(AVPacket);
 
@@ -59,6 +59,15 @@ impl Packet {
 		}
 	}
 
+	pub fn rescale_ts<S, D>(&mut self, source: S, destination: D)
+		where S: Into<Rational>,
+		      D: Into<Rational>
+	{
+		unsafe {
+			av_packet_rescale_ts(self.as_mut_ptr(), source.into().into(), destination.into().into());
+		}
+	}
+
 	pub fn flags(&self) -> Flags {
 		Flags::from_bits_truncate(self.0.flags)
 	}