contrib/ffmpeg: disable unused filters

Enables only filters that are used to reduce binary size.

Change-Id: I30270d6f032df3fcc927f373d284f10818e8f376
Reviewed-by: Sebastien Blin <sebastien.blin@savoirfairelinux.com>

contrib/src/ffmpeg/rules.mak

@@ -21,7 +21,7 @@ FFMPEGCONF += \
 	--enable-swscale \
 	--enable-protocols \
 	--enable-bsfs \
-	--enable-filters \
+	--disable-filters \
 	--disable-programs \
 	--disable-postproc
 
@@ -82,6 +82,17 @@ FFMPEGCONF += \
 	--enable-encoder=tiff \
 	--enable-decoder=tiff
 
+#filters
+FFMPEGCONF += \
+	--enable-filter=scale \
+	--enable-filter=overlay \
+	--enable-filter=amix \
+	--enable-filter=amerge \
+	--enable-filter=aresample \
+	--enable-filter=format \
+	--enable-filter=aformat \
+	--enable-filter=fps
+
 #platform specific options
 
 ifdef HAVE_WIN32