diff --git a/demboyz/demofile/demofile.cpp b/demboyz/demofile/demofile.cpp
index 091fb3c..767cd66 100644
--- a/demboyz/demofile/demofile.cpp
+++ b/demboyz/demofile/demofile.cpp
@@ -108,6 +108,11 @@ DemoFileWriter::DemoFileWriter(FILE* fp) :
 {
 }
 
+FILE* DemoFileWriter::GetFp() const
+{
+    return m_demoFp;
+}
+
 bool DemoFileWriter::IsOk() const
 {
     return ferror(m_demoFp) == 0;
diff --git a/demboyz/demofile/demofile.h b/demboyz/demofile/demofile.h
index 77e36a2..daeb602 100644
--- a/demboyz/demofile/demofile.h
+++ b/demboyz/demofile/demofile.h
@@ -32,6 +32,7 @@ class DemoFileWriter
 public:
     DemoFileWriter(FILE* fp);
 
+    FILE* GetFp() const;
     bool IsOk() const;
     void WriteDemoHeader(const demoheader_t& header);
     void WriteRawData(const uint8_t* buffer, int32_t length);
diff --git a/demboyz/io/demowriter.cpp b/demboyz/io/demowriter.cpp
index 33012df..dc04dbc 100644
--- a/demboyz/io/demowriter.cpp
+++ b/demboyz/io/demowriter.cpp
@@ -9,6 +9,30 @@
 #include <cstdio>
 #include <memory>
 
+#ifdef _WIN32
+#include <io.h>
+#else
+#include <unistd.h>
+#endif
+#include <sys/stat.h>
+
+int truncate(FILE* fp, int relative_offset)
+{
+    fflush(fp);
+#ifdef _WIN32
+    const int fd = _fileno(fp);
+#else
+    const int fd = fileno(fp);
+#endif
+    struct stat statbuf;
+    fstat(fd, &statbuf);
+#ifdef _WIN32
+    return _chsize_s(fd, statbuf.st_size + relative_offset);
+#else
+    return ftruncate(fd, statbuf.st_size + relative_offset);
+#endif
+}
+
 class DemoWriter: public IDemoWriter
 {
 public:
@@ -47,6 +71,9 @@ void DemoWriter::StartWriting(demoheader_t& header)
 
 void DemoWriter::EndWriting()
 {
+    // stv demos have a byte chopped off of the end
+    // i dunno why, just doit
+    truncate(m_writer.GetFp(), -1);
 }
 
 void DemoWriter::StartCommandPacket(const CommandPacket& packet)