diff --git a/libavformat/os_support.c b/libavformat/os_support.c
index 0a901f6bd2..dc88834bf3 100644
--- a/libavformat/os_support.c
+++ b/libavformat/os_support.c
@@ -36,6 +36,7 @@
 #include <io.h>
 #include <windows.h>
 #include <share.h>
+#include <errno.h>
 
 int ff_win32_open(const char *filename_utf8, int oflag, int pmode)
 {
@@ -48,8 +49,10 @@ int ff_win32_open(const char *filename_utf8, int oflag, int pmode)
     if (num_chars <= 0)
         goto fallback;
     filename_w = av_mallocz(sizeof(wchar_t) * num_chars);
-    if (!filename_w)
+    if (!filename_w) {
+        errno = ENOMEM;
         return -1;
+    }
     MultiByteToWideChar(CP_UTF8, 0, filename_utf8, -1, filename_w, num_chars);
 
     fd = _wsopen(filename_w, oflag, SH_DENYNO, pmode);
@@ -59,7 +62,7 @@ int ff_win32_open(const char *filename_utf8, int oflag, int pmode)
         return fd;
 
 fallback:
-    /* filename maybe be in CP_ACP */
+    /* filename may be be in CP_ACP */
     return _sopen(filename_utf8, oflag, SH_DENYNO, pmode);
 }
 #endif
diff --git a/libavutil/opt.c b/libavutil/opt.c
index a2cdcb4a17..97fc6fd9b5 100644
--- a/libavutil/opt.c
+++ b/libavutil/opt.c
@@ -1040,7 +1040,7 @@ static int parse_key_value_pair(void *ctx, const char **buf,
 
     av_log(ctx, AV_LOG_DEBUG, "Setting entry with key '%s' to value '%s'\n", key, val);
 
-    ret = av_opt_set(ctx, key, val, 0);
+    ret = av_opt_set(ctx, key, val, AV_OPT_SEARCH_CHILDREN);
     if (ret == AVERROR_OPTION_NOT_FOUND)
         av_log(ctx, AV_LOG_ERROR, "Key '%s' not found.\n", key);