file writer: fix file size calculation with dpl enabled

Author: ironMann

src/common/SubTimeFrameFileWriter.cxx

@@ -164,7 +164,8 @@ void SubTimeFrameFileWriter::visit(const SubTimeFrame& pStf)
       // NOTE: get only pointers to <hdr, data> struct
       mStfData.emplace_back(&lData);
       // account the size
-      const auto lHdrDataSize = lData.mHeader->GetSize() + lData.mData->GetSize();
+      // NOTE: only take data header. if DPL is enabled the header stack will already have the processing header
+      const auto lHdrDataSize = sizeof(DataHeader) + lData.mData->GetSize();
 
       // total size
       mStfSize += lHdrDataSize;