diff --git a/rtc_tools/video_file_reader.cc b/rtc_tools/video_file_reader.cc
index c6fa5870e8..6e722b1235 100644
--- a/rtc_tools/video_file_reader.cc
+++ b/rtc_tools/video_file_reader.cc
@@ -204,9 +204,10 @@ rtc::scoped_refptr<Video> OpenY4mFile(const std::string& file_name) {
   const int i420_frame_size = 3 * *width * *height / 2;
   std::vector<fpos_t> frame_positions;
   while (true) {
-    int parse_frame_header_result = -1;
-    if (fscanf(file, "FRAME\n%n", &parse_frame_header_result) != 0 ||
-        parse_frame_header_result == -1) {
+    std::array<char, 6> read_buffer;
+    if (fread(read_buffer.data(), 1, read_buffer.size(), file) <
+            read_buffer.size() ||
+        memcmp(read_buffer.data(), "FRAME\n", read_buffer.size()) != 0) {
       if (!feof(file)) {
         RTC_LOG(LS_ERROR) << "Did not find FRAME header, ignoring rest of file";
       }