contrib: add AMF package to enable AMF encoder in FFMPEG

contrib/src/amf/SHA512SUMS

@@ -0,0 +1 @@
+2c931ef7d38ade88a96041e0012605a5d25ec484bb2134f58310cf1a2c7212a869797cef99e2e751c8a6b3c473ba1f8762d4a5d41466d38cb5e31bf664a25f55  AMF-1.4.26.tar.gz

contrib/src/amf/rules.mak

@@ -0,0 +1,29 @@
+# AMF
+
+AMF_VERSION := 1.4.26
+AMF_URL := $(GITHUB)/GPUOpen-LibrariesAndSDKs/AMF/archive/refs/tags/v$(AMF_VERSION).tar.gz
+
+ifeq ($(ARCH),x86_64)
+ifdef HAVE_WIN32
+PKGS += amf
+endif
+ifdef HAVE_LINUX
+ifndef HAVE_ANDROID
+PKGS += amf
+endif
+endif
+endif
+
+$(TARBALLS)/AMF-$(AMF_VERSION).tar.gz:
+	$(call download_pkg,$(AMF_URL),AMF)
+
+.sum-amf: AMF-$(AMF_VERSION).tar.gz
+
+amf: AMF-$(AMF_VERSION).tar.gz .sum-amf
+	$(UNPACK)
+	$(MOVE)
+
+.amf: amf
+	mkdir -p $(PREFIX)/include/AMF
+	cp -R $(UNPACK_DIR)/amf/public/include/* $(PREFIX)/include/AMF
+	touch $@