diff --git a/msm8974/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp b/msm8974/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
index 1f898a3..dad7b4a 100644
--- a/msm8974/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
+++ b/msm8974/mm-video-v4l2/vidc/vdec/src/omx_vdec_msm8974.cpp
@@ -3303,6 +3303,13 @@
                                DEBUG_PRINT_LOW("set_parameter: OMX_IndexParamPortDefinition H= %d, W = %d",
                                        (int)portDefn->format.video.nFrameHeight,
                                        (int)portDefn->format.video.nFrameWidth);
+
+                               if (portDefn->nBufferCountActual > MAX_NUM_INPUT_OUTPUT_BUFFERS) {
+                                   DEBUG_PRINT_ERROR("ERROR: Buffers requested exceeds max limit %d",
+                                                          portDefn->nBufferCountActual);
+                                   eRet = OMX_ErrorBadParameter;
+                                   break;
+                               }
                                if (OMX_DirOutput == portDefn->eDir) {
                                    DEBUG_PRINT_LOW("set_parameter: OMX_IndexParamPortDefinition OP port");
                                    bool port_format_changed = false;
@@ -3413,8 +3420,11 @@
                                        eRet = OMX_ErrorBadParameter;
                                    } else if (!port_format_changed) {
 
-                                       // Buffer count can change only when port is disabled
-                                       if (!release_output_done()) {
+                                       // Buffer count can change only when port is unallocated
+                                       if (m_out_mem_ptr &&
+                                                (portDefn->nBufferCountActual != drv_ctx.op_buf.actualcount ||
+                                                portDefn->nBufferSize != drv_ctx.op_buf.buffer_size)) {
+
                                            DEBUG_PRINT_ERROR("Cannot change o/p buffer count since all buffers are not freed yet !");
                                            eRet = OMX_ErrorInvalidState;
                                            break;
@@ -3534,8 +3544,10 @@
                                        eRet = OMX_ErrorBadParameter;
                                        break;
                                    }
-                                   // Buffer count can change only when port is disabled
-                                   if (!release_input_done()) {
+                                   // Buffer count can change only when port is unallocated
+                                   if (m_inp_mem_ptr &&
+                                            (portDefn->nBufferCountActual != drv_ctx.ip_buf.actualcount ||
+                                            portDefn->nBufferSize != drv_ctx.ip_buf.buffer_size)) {
                                        DEBUG_PRINT_ERROR("Cannot change i/p buffer count since all buffers are not freed yet !");
                                        eRet = OMX_ErrorInvalidState;
                                        break;
@@ -3619,6 +3631,14 @@
 
                             /* Input port */
                             if (portFmt->nPortIndex == 0) {
+                                // arbitrary_bytes mode cannot be changed arbitrarily since this controls how:
+                                //   - headers are allocated and
+                                //   - headers-indices are derived
+                                // Avoid changing arbitrary_bytes when the port is already allocated
+                                if (m_inp_mem_ptr) {
+                                    DEBUG_PRINT_ERROR("Cannot change arbitrary-bytes-mode since input port is not free!");
+                                    return OMX_ErrorUnsupportedSetting;
+                                }
                                 if (portFmt->nFramePackingFormat == OMX_QCOM_FramePacking_Arbitrary) {
                                     if (secure_mode) {
                                         arbitrary_bytes = false;
@@ -3965,6 +3985,15 @@
         case OMX_GoogleAndroidIndexEnableAndroidNativeBuffers: {
                                            VALIDATE_OMX_PARAM_DATA(paramData, EnableAndroidNativeBuffersParams);
                                            EnableAndroidNativeBuffersParams* enableNativeBuffers = (EnableAndroidNativeBuffersParams *) paramData;
+                                           if (enableNativeBuffers->nPortIndex != OMX_CORE_OUTPUT_PORT_INDEX) {
+                                                DEBUG_PRINT_ERROR("Enable/Disable android-native-buffers allowed only on output port!");
+                                                eRet = OMX_ErrorUnsupportedSetting;
+                                                break;
+                                           } else if (m_out_mem_ptr) {
+                                                DEBUG_PRINT_ERROR("Enable/Disable android-native-buffers is not allowed since Output port is not free !");
+                                                eRet = OMX_ErrorInvalidState;
+                                                break;
+                                           }
                                            if (enableNativeBuffers) {
                                                m_enable_android_native_buffers = enableNativeBuffers->enable;
                                            }
@@ -3985,7 +4014,20 @@
                                    }
                                    break;
         case OMX_GoogleAndroidIndexAllocateNativeHandle: {
+
                 AllocateNativeHandleParams* allocateNativeHandleParams = (AllocateNativeHandleParams *) paramData;
+                VALIDATE_OMX_PARAM_DATA(paramData, AllocateNativeHandleParams);
+
+                if (allocateNativeHandleParams->nPortIndex != OMX_CORE_INPUT_PORT_INDEX) {
+                    DEBUG_PRINT_ERROR("Enable/Disable allocate-native-handle allowed only on input port!");
+                    eRet = OMX_ErrorUnsupportedSetting;
+                    break;
+                } else if (m_inp_mem_ptr) {
+                    DEBUG_PRINT_ERROR("Enable/Disable allocate-native-handle is not allowed since Input port is not free !");
+                    eRet = OMX_ErrorInvalidState;
+                    break;
+                }
+
                 if (allocateNativeHandleParams != NULL) {
                     allocate_native_handle = allocateNativeHandleParams->enable;
                 }
@@ -4036,6 +4078,12 @@
                 break;
             }
             if (metabuffer->nPortIndex == OMX_CORE_OUTPUT_PORT_INDEX) {
+
+                    if (m_out_mem_ptr) {
+                        DEBUG_PRINT_ERROR("Enable/Disable dynamic-buffer-mode is not allowed since Output port is not free !");
+                        eRet = OMX_ErrorInvalidState;
+                        break;
+                    }
                     //set property dynamic buffer mode to driver.
                     struct v4l2_control control;
                     struct v4l2_format fmt;
@@ -5030,9 +5078,16 @@
         DEBUG_PRINT_ERROR("Use Buffer in Invalid State");
         return OMX_ErrorInvalidState;
     }
-    if (port == OMX_CORE_INPUT_PORT_INDEX)
+    if (port == OMX_CORE_INPUT_PORT_INDEX) {
+        // If this is not the first allocation (i.e m_inp_mem_ptr is allocated),
+        // ensure that use-buffer was called for previous allocation.
+        // Mix-and-match of useBuffer and allocateBuffer is not allowed
+        if (m_inp_mem_ptr && !input_use_buffer) {
+            DEBUG_PRINT_ERROR("'Use' Input buffer called after 'Allocate' Input buffer !");
+            return OMX_ErrorUndefined;
+        }
         error = use_input_heap_buffers(hComp, bufferHdr, port, appData, bytes, buffer);
-    else if (port == OMX_CORE_OUTPUT_PORT_INDEX)
+    } else if (port == OMX_CORE_OUTPUT_PORT_INDEX)
         error = use_output_buffer(hComp,bufferHdr,port,appData,bytes,buffer); //not tested
     else {
         DEBUG_PRINT_ERROR("Error: Invalid Port Index received %d",(int)port);
@@ -5833,6 +5888,13 @@
     }
 
     if (port == OMX_CORE_INPUT_PORT_INDEX) {
+        // If this is not the first allocation (i.e m_inp_mem_ptr is allocated),
+        // ensure that use-buffer was never called.
+        // Mix-and-match of useBuffer and allocateBuffer is not allowed
+        if (m_inp_mem_ptr && input_use_buffer) {
+            DEBUG_PRINT_ERROR("'Allocate' Input buffer called after 'Use' Input buffer !");
+            return OMX_ErrorUndefined;
+        }
         if (arbitrary_bytes) {
             eRet = allocate_input_heap_buffer (hComp,bufferHdr,port,appData,bytes);
         } else {
@@ -6091,6 +6153,10 @@
     } else {
         if (input_use_buffer == true) {
             nBufferIndex = buffer - m_inp_heap_ptr;
+            if (nBufferIndex >= drv_ctx.ip_buf.actualcount ) {
+                DEBUG_PRINT_ERROR("ERROR: ETB nBufferIndex is invalid in use-buffer mode");
+                return OMX_ErrorBadParameter;
+            }
             m_inp_mem_ptr[nBufferIndex].nFilledLen = m_inp_heap_ptr[nBufferIndex].nFilledLen;
             m_inp_mem_ptr[nBufferIndex].nTimeStamp = m_inp_heap_ptr[nBufferIndex].nTimeStamp;
             m_inp_mem_ptr[nBufferIndex].nFlags = m_inp_heap_ptr[nBufferIndex].nFlags;
@@ -6102,7 +6168,7 @@
         }
     }
 
-    if (nBufferIndex > drv_ctx.ip_buf.actualcount ) {
+    if (nBufferIndex >= drv_ctx.ip_buf.actualcount ) {
         DEBUG_PRINT_ERROR("ERROR:ETB nBufferIndex is invalid");
         return OMX_ErrorBadParameter;
     }
@@ -6159,7 +6225,7 @@
 
     nPortIndex = buffer-((OMX_BUFFERHEADERTYPE *)m_inp_mem_ptr);
 
-    if (nPortIndex > drv_ctx.ip_buf.actualcount) {
+    if (nPortIndex >= drv_ctx.ip_buf.actualcount) {
         DEBUG_PRINT_ERROR("ERROR:empty_this_buffer_proxy invalid nPortIndex[%u]",
                 nPortIndex);
         return OMX_ErrorBadParameter;
@@ -6480,7 +6546,7 @@
 
     nPortIndex = buffer-((OMX_BUFFERHEADERTYPE *)client_buffers.get_il_buf_hdr());
 
-    if (!bufferAdd || !bufferAdd->pBuffer || nPortIndex > drv_ctx.op_buf.actualcount) {
+    if (!bufferAdd || !bufferAdd->pBuffer || nPortIndex >= drv_ctx.op_buf.actualcount) {
         DEBUG_PRINT_ERROR("FTBProxy: ERROR: invalid buffer index, nPortIndex %u bufCount %u",
             nPortIndex, drv_ctx.op_buf.actualcount);
         return OMX_ErrorBadParameter;
@@ -7392,7 +7458,7 @@
         OMX_BUFFERHEADERTYPE* buffer)
 {
 
-    if (buffer == NULL || ((buffer - m_inp_mem_ptr) > (int)drv_ctx.ip_buf.actualcount)) {
+    if (buffer == NULL || ((buffer - m_inp_mem_ptr) >= (int)drv_ctx.ip_buf.actualcount)) {
         DEBUG_PRINT_ERROR("empty_buffer_done: ERROR bufhdr = %p", buffer);
         return OMX_ErrorBadParameter;
     }
diff --git a/msm8996/mm-video-v4l2/vidc/vdec/src/omx_vdec_v4l2.cpp b/msm8996/mm-video-v4l2/vidc/vdec/src/omx_vdec_v4l2.cpp
index 0fc2154..6eb0fb4 100644
--- a/msm8996/mm-video-v4l2/vidc/vdec/src/omx_vdec_v4l2.cpp
+++ b/msm8996/mm-video-v4l2/vidc/vdec/src/omx_vdec_v4l2.cpp
@@ -3875,7 +3875,7 @@
                                        (int)portDefn->format.video.nFrameHeight,
                                        (int)portDefn->format.video.nFrameWidth);
 
-                               if (portDefn->nBufferCountActual >= MAX_NUM_INPUT_OUTPUT_BUFFERS) {
+                               if (portDefn->nBufferCountActual > MAX_NUM_INPUT_OUTPUT_BUFFERS) {
                                    DEBUG_PRINT_ERROR("ERROR: Buffers requested exceeds max limit %d",
                                                           portDefn->nBufferCountActual);
                                    eRet = OMX_ErrorBadParameter;
@@ -3995,8 +3995,11 @@
                                        eRet = OMX_ErrorBadParameter;
                                    } else if (!port_format_changed) {
 
-                                       // Buffer count can change only when port is disabled
-                                       if (!release_output_done()) {
+                                       // Buffer count can change only when port is unallocated
+                                       if (m_out_mem_ptr &&
+                                                (portDefn->nBufferCountActual != drv_ctx.op_buf.actualcount ||
+                                                portDefn->nBufferSize != drv_ctx.op_buf.buffer_size)) {
+
                                            DEBUG_PRINT_ERROR("Cannot change o/p buffer count since all buffers are not freed yet !");
                                            eRet = OMX_ErrorInvalidState;
                                            break;
@@ -4116,8 +4119,10 @@
                                        eRet = OMX_ErrorBadParameter;
                                        break;
                                    }
-                                   // Buffer count can change only when port is disabled
-                                   if (!release_input_done()) {
+                                   // Buffer count can change only when port is unallocated
+                                   if (m_inp_mem_ptr &&
+                                            (portDefn->nBufferCountActual != drv_ctx.ip_buf.actualcount ||
+                                            portDefn->nBufferSize != drv_ctx.ip_buf.buffer_size)) {
                                        DEBUG_PRINT_ERROR("Cannot change i/p buffer count since all buffers are not freed yet !");
                                        eRet = OMX_ErrorInvalidState;
                                        break;
@@ -4210,6 +4215,14 @@
 
                             /* Input port */
                             if (portFmt->nPortIndex == 0) {
+                                // arbitrary_bytes mode cannot be changed arbitrarily since this controls how:
+                                //   - headers are allocated and
+                                //   - headers-indices are derived
+                                // Avoid changing arbitrary_bytes when the port is already allocated
+                                if (m_inp_mem_ptr) {
+                                    DEBUG_PRINT_ERROR("Cannot change arbitrary-bytes-mode since input port is not free!");
+                                    return OMX_ErrorUnsupportedSetting;
+                                }
                                 if (portFmt->nFramePackingFormat == OMX_QCOM_FramePacking_Arbitrary) {
                                     if (secure_mode || m_input_pass_buffer_fd) {
                                         arbitrary_bytes = false;
@@ -4569,6 +4582,15 @@
         case OMX_GoogleAndroidIndexEnableAndroidNativeBuffers: {
                                            VALIDATE_OMX_PARAM_DATA(paramData, EnableAndroidNativeBuffersParams);
                                            EnableAndroidNativeBuffersParams* enableNativeBuffers = (EnableAndroidNativeBuffersParams *) paramData;
+                                           if (enableNativeBuffers->nPortIndex != OMX_CORE_OUTPUT_PORT_INDEX) {
+                                                DEBUG_PRINT_ERROR("Enable/Disable android-native-buffers allowed only on output port!");
+                                                eRet = OMX_ErrorUnsupportedSetting;
+                                                break;
+                                           } else if (m_out_mem_ptr) {
+                                                DEBUG_PRINT_ERROR("Enable/Disable android-native-buffers is not allowed since Output port is not free !");
+                                                eRet = OMX_ErrorInvalidState;
+                                                break;
+                                           }
                                            if (enableNativeBuffers) {
                                                m_enable_android_native_buffers = enableNativeBuffers->enable;
                                            }
@@ -4633,6 +4655,12 @@
                 break;
             }
             if (metabuffer->nPortIndex == OMX_CORE_OUTPUT_PORT_INDEX) {
+
+                    if (m_out_mem_ptr) {
+                        DEBUG_PRINT_ERROR("Enable/Disable dynamic-buffer-mode is not allowed since Output port is not free !");
+                        eRet = OMX_ErrorInvalidState;
+                        break;
+                    }
                     //set property dynamic buffer mode to driver.
                     struct v4l2_control control;
                     struct v4l2_format fmt;
@@ -5769,9 +5797,16 @@
         DEBUG_PRINT_ERROR("Use Buffer in Invalid State");
         return OMX_ErrorInvalidState;
     }
-    if (port == OMX_CORE_INPUT_PORT_INDEX)
+    if (port == OMX_CORE_INPUT_PORT_INDEX) {
+        // If this is not the first allocation (i.e m_inp_mem_ptr is allocated),
+        // ensure that use-buffer was called for previous allocation.
+        // Mix-and-match of useBuffer and allocateBuffer is not allowed
+        if (m_inp_mem_ptr && !input_use_buffer) {
+            DEBUG_PRINT_ERROR("'Use' Input buffer called after 'Allocate' Input buffer !");
+            return OMX_ErrorUndefined;
+        }
         error = use_input_heap_buffers(hComp, bufferHdr, port, appData, bytes, buffer);
-    else if (port == OMX_CORE_OUTPUT_PORT_INDEX)
+    } else if (port == OMX_CORE_OUTPUT_PORT_INDEX)
         error = use_output_buffer(hComp,bufferHdr,port,appData,bytes,buffer); //not tested
     else {
         DEBUG_PRINT_ERROR("Error: Invalid Port Index received %d",(int)port);
@@ -6560,6 +6595,13 @@
     }
 
     if (port == OMX_CORE_INPUT_PORT_INDEX) {
+        // If this is not the first allocation (i.e m_inp_mem_ptr is allocated),
+        // ensure that use-buffer was never called.
+        // Mix-and-match of useBuffer and allocateBuffer is not allowed
+        if (m_inp_mem_ptr && input_use_buffer) {
+            DEBUG_PRINT_ERROR("'Allocate' Input buffer called after 'Use' Input buffer !");
+            return OMX_ErrorUndefined;
+        }
         if (arbitrary_bytes) {
             eRet = allocate_input_heap_buffer (hComp,bufferHdr,port,appData,bytes);
         } else {
@@ -6809,6 +6851,10 @@
     } else {
         if (input_use_buffer == true) {
             nBufferIndex = buffer - m_inp_heap_ptr;
+            if (nBufferIndex >= drv_ctx.ip_buf.actualcount ) {
+                DEBUG_PRINT_ERROR("ERROR: ETB nBufferIndex is invalid in use-buffer mode");
+                return OMX_ErrorBadParameter;
+            }
             m_inp_mem_ptr[nBufferIndex].nFilledLen = m_inp_heap_ptr[nBufferIndex].nFilledLen;
             m_inp_mem_ptr[nBufferIndex].nTimeStamp = m_inp_heap_ptr[nBufferIndex].nTimeStamp;
             m_inp_mem_ptr[nBufferIndex].nFlags = m_inp_heap_ptr[nBufferIndex].nFlags;
@@ -6820,7 +6866,7 @@
         }
     }
 
-    if (nBufferIndex > drv_ctx.ip_buf.actualcount ) {
+    if (nBufferIndex >= drv_ctx.ip_buf.actualcount ) {
         DEBUG_PRINT_ERROR("ERROR:ETB nBufferIndex is invalid");
         return OMX_ErrorBadParameter;
     }
@@ -6882,7 +6928,7 @@
 
     nPortIndex = buffer-((OMX_BUFFERHEADERTYPE *)m_inp_mem_ptr);
 
-    if (nPortIndex > drv_ctx.ip_buf.actualcount) {
+    if (nPortIndex >= drv_ctx.ip_buf.actualcount) {
         DEBUG_PRINT_ERROR("ERROR:empty_this_buffer_proxy invalid nPortIndex[%u]",
                 nPortIndex);
         return OMX_ErrorBadParameter;
@@ -7202,7 +7248,7 @@
 
     nPortIndex = buffer-((OMX_BUFFERHEADERTYPE *)client_buffers.get_il_buf_hdr());
 
-    if (bufferAdd == NULL || nPortIndex > drv_ctx.op_buf.actualcount) {
+    if (bufferAdd == NULL || nPortIndex >= drv_ctx.op_buf.actualcount) {
         DEBUG_PRINT_ERROR("FTBProxy: ERROR: invalid buffer index, nPortIndex %u bufCount %u",
             nPortIndex, drv_ctx.op_buf.actualcount);
         return OMX_ErrorBadParameter;
@@ -8107,7 +8153,7 @@
 
     int nBufferIndex = buffer - m_inp_mem_ptr;
 
-    if (buffer == NULL || (nBufferIndex > (int)drv_ctx.ip_buf.actualcount)) {
+    if (buffer == NULL || (nBufferIndex >= (int)drv_ctx.ip_buf.actualcount)) {
         DEBUG_PRINT_ERROR("empty_buffer_done: ERROR bufhdr = %p", buffer);
         return OMX_ErrorBadParameter;
     }