diff --git a/include/media/stagefright/FileSource.h b/include/media/stagefright/FileSource.h
index a981d1c2d631fd261fb17d4095c441d607b93553..266168bdcfc846ef4a0c8ada89961b75da067814 100644
--- a/include/media/stagefright/FileSource.h
+++ b/include/media/stagefright/FileSource.h
@@ -56,7 +56,7 @@ private:
     sp<DecryptHandle> mDecryptHandle;
     DrmManagerClient *mDrmManagerClient;
     int64_t mDrmBufOffset;
-    size_t mDrmBufSize;
+    ssize_t mDrmBufSize;
     unsigned char *mDrmBuf;
 
     ssize_t readAtDRM(off64_t offset, void *data, size_t size);
diff --git a/media/libstagefright/FileSource.cpp b/media/libstagefright/FileSource.cpp
index 565f1562c4392e0ae841e73fa6cd8ed9aa051d03..37053ec8cf25f6f111a49349323b13973850303e 100644
--- a/media/libstagefright/FileSource.cpp
+++ b/media/libstagefright/FileSource.cpp
@@ -166,7 +166,7 @@ ssize_t FileSource::readAtDRM(off64_t offset, void *data, size_t size) {
     }
 
     if (mDrmBuf != NULL && mDrmBufSize > 0 && (offset + mOffset) >= mDrmBufOffset
-            && (offset + mOffset + size) <= (mDrmBufOffset + mDrmBufSize)) {
+            && (offset + mOffset + size) <= static_cast<size_t>(mDrmBufOffset + mDrmBufSize)) {
         /* Use buffered data */
         memcpy(data, (void*)(mDrmBuf+(offset+mOffset-mDrmBufOffset)), size);
         return size;
@@ -177,7 +177,7 @@ ssize_t FileSource::readAtDRM(off64_t offset, void *data, size_t size) {
                 DRM_CACHE_SIZE, offset + mOffset);
         if (mDrmBufSize > 0) {
             int64_t dataRead = 0;
-            dataRead = size > mDrmBufSize ? mDrmBufSize : size;
+            dataRead = size > static_cast<size_t>(mDrmBufSize) ? mDrmBufSize : size;
             memcpy(data, (void*)mDrmBuf, dataRead);
             return dataRead;
         } else {