diff --git a/gvsbuild/patches/ffmpeg/build/build.sh b/gvsbuild/patches/ffmpeg/build/build.sh
index eeb3fceee..45a578b56 100644
--- a/gvsbuild/patches/ffmpeg/build/build.sh
+++ b/gvsbuild/patches/ffmpeg/build/build.sh
@@ -15,6 +15,8 @@ configure_cmd[idx++]="--enable-shared"
 configure_cmd[idx++]="--disable-everything"
 configure_cmd[idx++]="--enable-swscale"
 configure_cmd[idx++]="--enable-avcodec"
+configure_cmd[idx++]="--enable-avfilter"
+configure_cmd[idx++]="--enable-avformat"
 configure_cmd[idx++]="--enable-hwaccel=av1_dxva2"
 configure_cmd[idx++]="--enable-hwaccel=h264_dxva2"
 configure_cmd[idx++]="--enable-hwaccel=hevc_dxva2"
@@ -37,8 +39,6 @@ configure_cmd[idx++]="--enable-hwaccel=av1_nvdec"
 configure_cmd[idx++]="--enable-hwaccel=h264_nvdec"
 configure_cmd[idx++]="--enable-hwaccel=hevc_nvdec"
 configure_cmd[idx++]="--disable-programs"
-configure_cmd[idx++]="--disable-avformat"
-configure_cmd[idx++]="--disable-avfilter"
 configure_cmd[idx++]="--disable-avdevice"
 configure_cmd[idx++]="--disable-swresample"
 configure_cmd[idx++]="--disable-postproc"
diff --git a/gvsbuild/patches/zlib/001-fix-ffmpeg-build-failure.patch b/gvsbuild/patches/zlib/001-fix-ffmpeg-build-failure.patch
new file mode 100644
index 000000000..714b8d020
--- /dev/null
+++ b/gvsbuild/patches/zlib/001-fix-ffmpeg-build-failure.patch
@@ -0,0 +1,70 @@
+From 7108497fda9d4536a1afade7f42266e06dca4488 Mon Sep 17 00:00:00 2001
+From: Mark Adler <madler@alumni.caltech.edu>
+Date: Thu, 13 Feb 2025 22:44:48 -0800
+Subject: [PATCH] Check that HAVE_UNISTD_H and HAVE_STDARG_H are not defined as
+ 0.
+
+---
+ configure  | 4 ++--
+ zconf.h    | 4 ++--
+ zconf.h.in | 4 ++--
+ 3 files changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/configure b/configure
+index 393c23c94..1834659fd 100755
+--- a/configure
++++ b/configure
+@@ -611,7 +611,7 @@ cat > $test.c <<EOF
+ int main() { return 0; }
+ EOF
+ if try $CC -c $CFLAGS $test.c; then
+-  sed < zconf.h "/^#ifdef HAVE_UNISTD_H.* may be/s/def HAVE_UNISTD_H\(.*\) may be/ 1\1 was/" > zconf.temp.h
++  sed < zconf.h "/^#if HAVE_UNISTD_H-0.* may be/s/ HAVE_UNISTD_H-0\(.*\) may be/ 1\1 was/" > zconf.temp.h
+   mv zconf.temp.h zconf.h
+   echo "Checking for unistd.h... Yes." | tee -a configure.log
+ else
+@@ -626,7 +626,7 @@ cat > $test.c <<EOF
+ int main() { return 0; }
+ EOF
+ if try $CC -c $CFLAGS $test.c; then
+-  sed < zconf.h "/^#ifdef HAVE_STDARG_H.* may be/s/def HAVE_STDARG_H\(.*\) may be/ 1\1 was/" > zconf.temp.h
++  sed < zconf.h "/^#if HAVE_STDARG_H-0.* may be/s/ HAVE_STDARG_H-0\(.*\) may be/ 1\1 was/" > zconf.temp.h
+   mv zconf.temp.h zconf.h
+   echo "Checking for stdarg.h... Yes." | tee -a configure.log
+ else
+diff --git a/zconf.h b/zconf.h
+index d6c159a1e..bc3ef079b 100644
+--- a/zconf.h
++++ b/zconf.h
+@@ -436,11 +436,11 @@ typedef uLong FAR uLongf;
+    typedef unsigned long z_crc_t;
+ #endif
+
+-#ifdef HAVE_UNISTD_H    /* may be set to #if 1 by ./configure */
++#if HAVE_UNISTD_H-0     /* may be set to #if 1 by ./configure */
+ #  define Z_HAVE_UNISTD_H
+ #endif
+
+-#ifdef HAVE_STDARG_H    /* may be set to #if 1 by ./configure */
++#if HAVE_STDARG_H-0     /* may be set to #if 1 by ./configure */
+ #  define Z_HAVE_STDARG_H
+ #endif
+
+diff --git a/zconf.h.in b/zconf.h.in
+index d6c159a1e..bc3ef079b 100644
+--- a/zconf.h.in
++++ b/zconf.h.in
+@@ -436,11 +436,11 @@ typedef uLong FAR uLongf;
+    typedef unsigned long z_crc_t;
+ #endif
+
+-#ifdef HAVE_UNISTD_H    /* may be set to #if 1 by ./configure */
++#if HAVE_UNISTD_H-0     /* may be set to #if 1 by ./configure */
+ #  define Z_HAVE_UNISTD_H
+ #endif
+
+-#ifdef HAVE_STDARG_H    /* may be set to #if 1 by ./configure */
++#if HAVE_STDARG_H-0     /* may be set to #if 1 by ./configure */
+ #  define Z_HAVE_STDARG_H
+ #endif
+
diff --git a/gvsbuild/projects/ffmpeg.py b/gvsbuild/projects/ffmpeg.py
index 8c23a4cdb..318c2675d 100644
--- a/gvsbuild/projects/ffmpeg.py
+++ b/gvsbuild/projects/ffmpeg.py
@@ -61,6 +61,8 @@ def build(self):
 
         if configuration in ["debug-optimized", "debug"]:
             self.install(r".\libavcodec\avcodec-60.pdb bin")
+            self.install(r".\libavfilter\avfilter-10.pdb bin")
+            self.install(r".\libavformat\avformat-61.pdb bin")
             self.install(r".\libavutil\avutil-58.pdb bin")
             self.install(r".\libswscale\libswscale-7.pdb bin")
 
@@ -69,7 +71,13 @@ def build(self):
             self.install(r".\COPYING.GPLv2 " r"share\doc\ffmpeg")
 
     def post_install(self):
-        for lib in ["avcodec.lib", "avutil.lib", "swscale.lib"]:
+        for lib in [
+            "avcodec.lib",
+            "avfilter.lib",
+            "avformat.lib",
+            "avutil.lib",
+            "swscale.lib",
+        ]:
             self.builder.exec_msys(
                 ["mv", lib, "../lib/"],
                 working_dir=os.path.join(self.builder.gtk_dir, "bin"),
diff --git a/gvsbuild/projects/zlib.py b/gvsbuild/projects/zlib.py
index 2a030e7b1..48fadc420 100644
--- a/gvsbuild/projects/zlib.py
+++ b/gvsbuild/projects/zlib.py
@@ -39,7 +39,9 @@ def __init__(self):
             version="1.3.1",
             archive_url="https://github.com/madler/zlib/releases/download/v{version}/zlib-{version}.tar.xz",
             hash="38ef96b8dfe510d42707d9c781877914792541133e1870841463bfa73f883e32",
-            patches=[],
+            patches=[
+                "001-fix-ffmpeg-build-failure.patch",
+            ],
         )
 
     def build(self):