diff --git a/media/libstagefright/matroska/MatroskaExtractor.cpp b/media/libstagefright/matroska/MatroskaExtractor.cpp
index 4fbf47ee979ca..9ba0e829adecd 100644
--- a/media/libstagefright/matroska/MatroskaExtractor.cpp
+++ b/media/libstagefright/matroska/MatroskaExtractor.cpp
@@ -768,12 +768,12 @@ void MatroskaExtractor::findThumbnails() {
         }
 
         BlockIterator iter(this, info->mTrackNum);
-        int32_t i = 0;
+        int32_t j = 0;
         int64_t thumbnailTimeUs = 0;
         size_t maxBlockSize = 0;
-        while (!iter.eos() && i < 20) {
+        while (!iter.eos() && j < 20) {
             if (iter.block()->IsKey()) {
-                ++i;
+                ++j;
 
                 size_t blockSize = 0;
                 for (int i = 0; i < iter.block()->GetFrameCount(); ++i) {