diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5a6f9b2e93..d0fd072a43 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -62,10 +62,10 @@ message(STATUS "We are using ${CMAKE_CXX_COMPILER_ID}")
 set_property(TARGET keeperfx PROPERTY LINKER_TYPE LLD)
 set_property(TARGET keeperfx_hvlog PROPERTY LINKER_TYPE LLD)
 
-set(WARNFLAGS -Wall -W -Wshadow -Wno-sign-compare -Wno-unused-parameter -Wno-strict-aliasing -Wno-unknown-pragmas)
+set(WARNFLAGS -Wall -W -Wshadow -Wno-sign-compare -Wno-unused-parameter -Wno-strict-aliasing -Wno-unknown-pragmas -Werror)
 set(GNU_COMPILER_FLAG -march=x86-64 -fno-omit-frame-pointer -fmessage-length=0)
 set(GNU_LINK_FLAG -mwindows -Wl,--enable-auto-import)
-SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror=implicit")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wimplicit")
 target_compile_options(keeperfx PRIVATE ${WARNFLAGS} ${GNU_COMPILER_FLAG})
 target_compile_options(keeperfx_hvlog PRIVATE ${WARNFLAGS} ${GNU_COMPILER_FLAG})
 target_link_options(keeperfx PRIVATE ${GNU_LINK_FLAG} -Wl,-Map,keeperfx.map)
diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index 8a3ed7e148..4f6f3d7fc9 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -46,6 +46,15 @@ if( NOT EXISTS ${CMAKE_SOURCE_DIR}/deps/centijson )
 	execute_process(COMMAND ${CMAKE_COMMAND} -E tar xzf ${CMAKE_SOURCE_DIR}/deps/centijson-mingw32.tar.gz WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/deps/centijson)
 endif()
 
+if(NOT EXISTS ${CMAKE_SOURCE_DIR}/deps/ffmpeg)
+	file(MAKE_DIRECTORY ${CMAKE_SOURCE_DIR}/deps/ffmpeg)
+	if(NOT EXISTS ${CMAKE_SOURCE_DIR}/deps/ffmpeg-mingw32.tar.gz)
+		file(DOWNLOAD https://github.com/dkfans/kfx-deps/releases/download/initial/ffmpeg-mingw32.tar.gz ${CMAKE_SOURCE_DIR}/deps/ffmpeg-mingw32.tar.gz SHOW_PROGRESS)
+	endif()
+
+	execute_process(COMMAND ${CMAKE_COMMAND} -E tar xzf ${CMAKE_SOURCE_DIR}/deps/ffmpeg-mingw32.tar.gz WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/deps/ffmpeg)
+endif()
+
 ## enet
 add_library(enet_static STATIC IMPORTED)
 set_target_properties(enet_static PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/enet/libenet.a)
@@ -96,3 +105,23 @@ target_link_libraries(centitoml PUBLIC centijson_static)
 target_include_directories(centitoml INTERFACE "centitoml")
 target_link_libraries(keeperfx PUBLIC centitoml)
 target_link_libraries(keeperfx_hvlog PUBLIC centitoml)
+
+## ffmpeg
+add_library(libavcodec_static STATIC IMPORTED)
+set_target_properties(libavcodec_static PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg/libavcodec/libavcodec.a)
+set_target_properties(libavcodec_static PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg)
+
+add_library(libavformat_static STATIC IMPORTED)
+set_target_properties(libavformat_static PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg/libavformat/libavformat.a)
+set_target_properties(libavformat_static PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg)
+
+add_library(libavutil_static STATIC IMPORTED)
+set_target_properties(libavutil_static PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg/libavutil/libavutil.a)
+set_target_properties(libavutil_static PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg)
+
+add_library(libswresample_static STATIC IMPORTED)
+set_target_properties(libswresample_static PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg/libswresample/libswresample.a)
+set_target_properties(libswresample_static PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/ffmpeg)
+
+target_link_libraries(keeperfx PUBLIC bcrypt libavcodec_static libavformat_static libavutil_static libswresample_static)
+target_link_libraries(keeperfx_hvlog PUBLIC bcrypt libavcodec_static libavformat_static libavutil_static libswresample_static)
diff --git a/src/bflib_fmvids.cpp b/src/bflib_fmvids.cpp
index cddc8548c1..03950bdc4b 100644
--- a/src/bflib_fmvids.cpp
+++ b/src/bflib_fmvids.cpp
@@ -13,6 +13,7 @@ extern "C" {
 	#include <libavcodec/avcodec.h>
 	#include <libavutil/imgutils.h>
 	#include <libswresample/swresample.h>
+    #pragma GCC diagnostic warning "-Wdeprecated-declarations"
 }
 
 #include <cstdio>
diff --git a/src/globals.h b/src/globals.h
index f7ba28be33..ceecb77bf4 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -19,9 +19,10 @@
 #ifndef KEEPFX_GLOBALS_H
 #define KEEPFX_GLOBALS_H
 
+#include <stdbool.h> // Introduced in C99. Provides true/false.
 #include <stdio.h>
 #include <stdint.h>
-#include <stdlib.h>
+#include <stdlib.h> // Provides NULL.
 #include <string.h>
 #include <ctype.h>
 #include <limits.h>
@@ -72,16 +73,6 @@ extern "C" {
 #define SEPARATOR "\\"
 #endif
 
-#ifndef false
-#define false 0
-#endif
-#ifndef true
-#define true 1
-#endif
-#ifndef NULL
-#define NULL 0
-#endif
-
 #ifndef __cplusplus
 #ifndef max
 #define max(a,b) ((a)>(b)?(a):(b))