diff --git a/modules/core/include/opencv2/core/operations.hpp b/modules/core/include/opencv2/core/operations.hpp
index 9fce43b346..87e6ad8ff0 100644
--- a/modules/core/include/opencv2/core/operations.hpp
+++ b/modules/core/include/opencv2/core/operations.hpp
@@ -2311,13 +2311,13 @@ inline Point LineIterator::pos() const
 
 template<typename _Tp, size_t fixed_size> inline AutoBuffer<_Tp, fixed_size>::AutoBuffer()
 {
-    ptr = alignPtr(buf, 16);
+    ptr = buf;
     size = fixed_size;
 }
 
 template<typename _Tp, size_t fixed_size> inline AutoBuffer<_Tp, fixed_size>::AutoBuffer(size_t _size)
 {
-    ptr = alignPtr(buf, 16);
+    ptr = buf;
     size = fixed_size;
     allocate(_size);
 }
@@ -2339,11 +2339,10 @@ template<typename _Tp, size_t fixed_size> inline void AutoBuffer<_Tp, fixed_size
 
 template<typename _Tp, size_t fixed_size> inline void AutoBuffer<_Tp, fixed_size>::deallocate()
 {
-    _Tp* buf0 = alignPtr(buf, 16);
-    if( ptr != buf0 )
+    if( ptr != buf )
     {
         cv::deallocate<_Tp>(ptr, size);
-        ptr = buf0;
+        ptr = buf;
         size = fixed_size;
     }
 }
diff --git a/modules/core/src/convert.cpp b/modules/core/src/convert.cpp
index 58243d192c..76d117f089 100644
--- a/modules/core/src/convert.cpp
+++ b/modules/core/src/convert.cpp
@@ -1130,11 +1130,19 @@ cvMixChannels( const CvArr** src, int src_count,
                CvArr** dst, int dst_count,
                const int* from_to, int pair_count )
 {
-    cv::AutoBuffer<cv::Mat, 32> buf;
+    cv::AutoBuffer<cv::Mat, 32> buf(src_count + dst_count);
 
     int i;
     for( i = 0; i < src_count; i++ )
+    {
+        printf("%d. %p ", i, src[i]);
+        if( src[i] )
+        {
+            CvMat m, *pm = cvGetMat(src[i], &m);
+            printf( "%d x %d, type = %d\n", pm->rows, pm->cols, CV_MAT_TYPE(pm->type));
+        }
         buf[i] = cv::cvarrToMat(src[i]);
+    }
     for( i = 0; i < dst_count; i++ )
         buf[i+src_count] = cv::cvarrToMat(dst[i]);
     cv::mixChannels(&buf[0], src_count, &buf[src_count], dst_count, from_to, pair_count);
diff --git a/modules/core/src/stat.cpp b/modules/core/src/stat.cpp
index e514d80d02..f0c2e0be3c 100644
--- a/modules/core/src/stat.cpp
+++ b/modules/core/src/stat.cpp
@@ -60,7 +60,7 @@ template<typename T> static inline Scalar rawToScalar(const T& v)
 \****************************************************************************************/
 
 template<typename T, typename ST>
-static size_t sum_(const T* src0, const uchar* mask, ST* dst, int len, int cn )
+static int sum_(const T* src0, const uchar* mask, ST* dst, int len, int cn )
 {
     const T* src = src0;
     if( !mask )
@@ -537,7 +537,7 @@ void cv::meanStdDev( const InputArray& _src, OutputArray _mean, OutputArray _sdv
     const Mat* arrays[] = {&src, &mask, 0};
     uchar* ptrs[2];
     NAryMatIterator it(arrays, ptrs);
-    int total = it.size, blockSize = total, intSumBlockSize = 0;
+    int total = (int)it.size, blockSize = total, intSumBlockSize = 0;
     int j, count = 0, nz0 = 0;
     AutoBuffer<double> _buf(cn*4);
     double *s = (double*)_buf, *sq = s + cn;
@@ -954,11 +954,11 @@ normDiffL2_(const T* src1, const T* src2, const uchar* mask, ST* _result, int le
 
 
 #define CV_DEF_NORM_FUNC(L, suffix, type, ntype) \
-static int norm##L##_##suffix(const type* src, const uchar* mask, ntype* r, size_t len, int cn) \
+static int norm##L##_##suffix(const type* src, const uchar* mask, ntype* r, int len, int cn) \
 { return norm##L##_(src, mask, r, len, cn); } \
 static int normDiff##L##_##suffix(const type* src1, const type* src2, \
-                               const uchar* mask, ntype* r, size_t len, int cn) \
-{ return normDiff##L##_(src1, src2, mask, r, len, cn); }
+                               const uchar* mask, ntype* r, int len, int cn) \
+{ return normDiff##L##_(src1, src2, mask, r, (int)len, cn); }
     
 #define CV_DEF_NORM_ALL(suffix, type, inftype, l1type, l2type) \
 CV_DEF_NORM_FUNC(Inf, suffix, type, inftype) \
diff --git a/modules/features2d/src/matchers.cpp b/modules/features2d/src/matchers.cpp
index 82ae5c19db..6a4cafda55 100755
--- a/modules/features2d/src/matchers.cpp
+++ b/modules/features2d/src/matchers.cpp
@@ -162,7 +162,7 @@ void DescriptorMatcher::DescriptorCollection::getLocalIdx( int globalDescIdx, in
     CV_Assert( (globalDescIdx>=0) && (globalDescIdx < size()) );
     std::vector<int>::const_iterator img_it = std::upper_bound(startIdxs.begin(), startIdxs.end(), globalDescIdx);
     --img_it;
-    imgIdx = img_it - startIdxs.begin();
+    imgIdx = (int)(img_it - startIdxs.begin());
     localDescIdx = globalDescIdx - (*img_it);
 }
 
diff --git a/modules/imgproc/src/contours.cpp b/modules/imgproc/src/contours.cpp
index bc57a01b00..485476afb9 100644
--- a/modules/imgproc/src/contours.cpp
+++ b/modules/imgproc/src/contours.cpp
@@ -1485,14 +1485,14 @@ void cv::findContours( const InputOutputArray _image, OutputArrayOfArrays _conto
         return;
     }
     Seq<CvSeq*> all_contours(cvTreeToNodeSeq( _ccontours, sizeof(CvSeq), storage ));
-    size_t i, total = all_contours.size();
+    int i, total = (int)all_contours.size();
     _contours.create(total, 1, 0, -1, true);
     SeqIterator<CvSeq*> it = all_contours.begin();
     for( i = 0; i < total; i++, ++it )
     {
         CvSeq* c = *it;
         ((CvContour*)c)->color = (int)i;
-        _contours.create(c->total, 1, CV_32SC2, i, true);
+        _contours.create((int)c->total, 1, CV_32SC2, i, true);
         Mat ci = _contours.getMat(i);
         CV_Assert( ci.isContinuous() );
         cvCvtSeqToArray(c, ci.data);
@@ -1583,7 +1583,7 @@ void cv::drawContours( InputOutputArray _image, const InputArrayOfArrays& _conto
     
     for( i = first; i < last; i++ )
     {
-        Mat ci = _contours.getMat(i);
+        Mat ci = _contours.getMat((int)i);
         if( ci.empty() )
             continue;
         int npoints = ci.checkVector(2, CV_32S);