diff --git a/configure b/configure
index b7f0acdc0a42e29ac0c494a7a6bd12d073e32fdc..481f0eacaf3fc9b3b812b31b2475d136685f9ba6 100755
--- a/configure
+++ b/configure
@@ -1084,9 +1084,9 @@ HAVE_LIST="
     fork
     getaddrinfo
     gethrtime
+    GetProcessAffinityMask
     GetProcessMemoryInfo
     GetProcessTimes
-    GetSystemInfo
     getrusage
     gnu_as
     ibm_asm
@@ -2864,8 +2864,8 @@ check_func  sysctl
 check_func_headers io.h setmode
 check_func_headers lzo/lzo1x.h lzo1x_999_compress
 check_lib2 "windows.h psapi.h" GetProcessMemoryInfo -lpsapi
+check_func_headers windows.h GetProcessAffinityMask
 check_func_headers windows.h GetProcessTimes
-check_func_headers windows.h GetSystemInfo
 check_func_headers windows.h MapViewOfFile
 check_func_headers windows.h VirtualAlloc
 
diff --git a/libavcodec/pthread.c b/libavcodec/pthread.c
index 58c5fcd638c7e574f18a540752fe630b384d9383..2159a2572df7f2cae87bb1b1ffd692bca4a4c45e 100644
--- a/libavcodec/pthread.c
+++ b/libavcodec/pthread.c
@@ -35,7 +35,7 @@
 #define _GNU_SOURCE
 #include <sched.h>
 #endif
-#if HAVE_GETSYSTEMINFO
+#if HAVE_GETPROCESSAFFINITYMASK
 #include <windows.h>
 #endif
 #if HAVE_SYSCTL
@@ -169,10 +169,11 @@ static int get_logical_cpus(AVCodecContext *avctx)
     if (!ret) {
         nb_cpus = CPU_COUNT(&cpuset);
     }
-#elif HAVE_GETSYSTEMINFO
-    SYSTEM_INFO sysinfo;
-    GetSystemInfo(&sysinfo);
-    nb_cpus = sysinfo.dwNumberOfProcessors;
+#elif HAVE_GETPROCESSAFFINITYMASK
+    DWORD_PTR proc_aff, sys_aff;
+    ret = GetProcessAffinityMask(GetCurrentProcess(), &proc_aff, &sys_aff);
+    if (ret)
+        nb_cpus = av_popcount64(proc_aff);
 #elif HAVE_SYSCTL && defined(HW_NCPU)
     int mib[2] = { CTL_HW, HW_NCPU };
     size_t len = sizeof(nb_cpus);