From d84260b0307157570b19b7a83096a1115f7870f0 Mon Sep 17 00:00:00 2001
From: Michael Pacella <mpacella88@gmail.com>
Date: Thu, 11 Feb 2016 01:13:22 -0500
Subject: [PATCH] realized that having bestaudio as a file extension is
 perfectly valid in this case so there is no need to tack m4a on arbitrarily

---
 youtube_dl.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/youtube_dl.go b/youtube_dl.go
index 5139e1a..ff39510 100644
--- a/youtube_dl.go
+++ b/youtube_dl.go
@@ -167,7 +167,7 @@ func (dl *AudioTrack) ID() string {
 
 // Filename returns the filename of the Song.
 func (dl *AudioTrack) Filename() string {
-	return dl.id + ".m4a"
+	return dl.id + "." + dl.format
 }
 
 // Duration returns duration for the Song.