diff --git a/src/parser/hevc_parser.cpp b/src/parser/hevc_parser.cpp
index a03f75eadc..07c6dc1627 100644
--- a/src/parser/hevc_parser.cpp
+++ b/src/parser/hevc_parser.cpp
@@ -566,7 +566,7 @@ ParserResult HevcVideoParser::ParsePictureData(const uint8_t* p_stream, uint32_t
             return ret;
         }
         // Parse the NAL unit
-        if (nal_unit_size_) {
+        if (nal_unit_size_ >= 5) {
             // start code + NAL unit header = 5 bytes
             int ebsp_size = nal_unit_size_ - 5 > RBSP_BUF_SIZE ? RBSP_BUF_SIZE : nal_unit_size_ - 5; // only copy enough bytes for header parsing
 
diff --git a/src/parser/roc_video_parser.cpp b/src/parser/roc_video_parser.cpp
index e146a554b9..499fdce3fb 100644
--- a/src/parser/roc_video_parser.cpp
+++ b/src/parser/roc_video_parser.cpp
@@ -139,11 +139,10 @@ ParserResult RocVideoParser::GetNalUnit() {
             start_code_found = true;
             start_code_num_++;
             next_start_code_offset_ = curr_byte_offset_;
-            // Move the pointer (3 + 2) bytes forward (start_code + nal header)
-            curr_byte_offset_ += 5;
+            // Move the pointer 3 bytes forward
+            curr_byte_offset_ += 3;
 
             // For the very first NAL unit, search for the next start code (or reach the end of frame)
-            // also detect empty nal units with no data
             if (start_code_num_ == 1 ) {
                 start_code_found = false;
                 curr_start_code_offset_ = next_start_code_offset_;
@@ -153,7 +152,7 @@ ParserResult RocVideoParser::GetNalUnit() {
             }
         }
         curr_byte_offset_++;
-    }    
+    }
     if (start_code_num_ == 0) {
         // No NAL unit in the frame data
         return PARSER_NOT_FOUND;
@@ -164,7 +163,7 @@ ParserResult RocVideoParser::GetNalUnit() {
     } else {
         nal_unit_size_ = pic_data_size_ - curr_start_code_offset_;
         return PARSER_EOF;
-    }        
+    }
 }
 
 size_t RocVideoParser::EbspToRbsp(uint8_t *streamBuffer,size_t begin_bytepos, size_t end_bytepos) {