diff --git a/packager/media/demuxer/demuxer.cc b/packager/media/demuxer/demuxer.cc
index 6751b29d1d..39769835d1 100644
--- a/packager/media/demuxer/demuxer.cc
+++ b/packager/media/demuxer/demuxer.cc
@@ -164,8 +164,8 @@ Status Demuxer::InitializeParser() {
   }
 
   // Read enough bytes before detecting the container.
-  size_t bytes_read = 0;
-  while (bytes_read < kInitBufSize) {
+  int64_t bytes_read = 0;
+  while (static_cast<size_t>(bytes_read) < kInitBufSize) {
     int64_t read_result =
         media_file_->Read(buffer_.get() + bytes_read, kInitBufSize);
     if (read_result < 0)