Add targets to fetch and build ffmpeg on demand

jni/.gitignore

@@ -0,0 +1,3 @@
+ffmpeg-android
+stamp.c
+*~

jni/Android.mk

@@ -4,16 +4,32 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := decoder-jni
 LOCAL_CPPFLAGS := -D__STDC_CONSTANT_MACROS
 LOCAL_C_INCLUDES := ffmpeg-android/build/ffmpeg/${TARGET_ARCH_ABI}/include
-LOCAL_SRC_FILES := decoder-jni.c
-LOCAL_STATIC_LIBRARIES += \
-    avcodec \
-    avcore \
-    avutil \
-    swscale \
-#
-LOCAL_LDLIBS += \
+LOCAL_SRC_FILES := stamp.c decoder-jni.c
+LOCAL_STATIC_LIBRARIES := 
+
+LOCAL_LDLIBS += -Lffmpeg-android/build/ffmpeg/${TARGET_ARCH_ABI}/lib \
     -ljnigraphics \
+    -lavformat \
+    -lavcodec \
+    -lavcore \
+    -lavutil \
+    -lswscale \
 #
+
+$(LOCAL_PATH)/stamp.c: $(LOCAL_PATH)/ffmpeg-android/build/ffmpeg/armeabi
+	echo "Generate file"
+	touch stamp.c
+
+$(LOCAL_PATH)/ffmpeg-android/build/ffmpeg/${TARGET_ARCH_ABI}: $(LOCAL_PATH)/ffmpeg-android/ffmpeg
+	echo ANDROIDNDK="$(NDK_ROOT)"
+	cd ffmpeg-android && ANDROIDNDK="$(NDK_ROOT)" FFMPEG_ARCHS="armv7a" ./build-h264-aac.sh
+	cd ffmpeg-android/build/ffmpeg/ && ln -s armeabi-v7a ${TARGET_ARCH_ABI}
+
+$(LOCAL_PATH)/ffmpeg-android/ffmpeg: $(LOCAL_PATH)/ffmpeg-android
+	cd ffmpeg-android && ./extract.sh
+
+$(LOCAL_PATH)/ffmpeg-android:
+	git clone git://github.com/tito/ffmpeg-android.git
+
 include $(BUILD_SHARED_LIBRARY)
 
-include ffmpeg-android/Android.mk