msdk_mvc: Unescape SEI NALs before parsing them

2 files changed, 51 insertions, 0 deletions

diff --git a/common/DSUtilLite/H264Nalu.cpp b/common/DSUtilLite/H264Nalu.cpp
index 4ee5e20a..578b86f1 100644
--- a/common/DSUtilLite/H264Nalu.cpp
+++ b/common/DSUtilLite/H264Nalu.cpp
@@ -114,3 +114,41 @@ bool CH265Nalu::ReadNext()
 
   return false;
 }
+
+
+CH264NALUnescape::CH264NALUnescape(const BYTE *src, size_t nSize)
+{
+  m_pBuffer = (BYTE *)_aligned_malloc(nSize + 16, 16);
+  memset(m_pBuffer, 0, nSize + 16);
+
+  unsigned si = 0, di = 0;
+  BYTE *dst = m_pBuffer;
+  while (si + 2 < nSize) {
+    // detect and remove escapes
+    if (src[si + 2] > 3) {
+      dst[di++] = src[si++];
+      dst[di++] = src[si++];
+    }
+    else if (src[si] == 0 && src[si + 1] == 0 && src[si + 2] != 0) {
+      if (src[si + 2] == 3) { // escape
+        dst[di++] = 0;
+        dst[di++] = 0;
+        si += 3;
+
+        continue;
+      }
+    }
+
+    dst[di++] = src[si++];
+  }
+
+  while (si < nSize)
+    dst[di++] = src[si++];
+
+  m_nSize = di;
+}
+
+CH264NALUnescape::~CH264NALUnescape()
+{
+  _aligned_free(m_pBuffer);
+}
diff --git a/common/DSUtilLite/H264Nalu.h b/common/DSUtilLite/H264Nalu.h
index cb68425f..d7f947f6 100644
--- a/common/DSUtilLite/H264Nalu.h
+++ b/common/DSUtilLite/H264Nalu.h
@@ -87,3 +87,16 @@ public:
   CH265Nalu() : CH264Nalu() {};
   bool ReadNext();
 };
+
+class CH264NALUnescape
+{
+public:
+  CH264NALUnescape(const BYTE *pBuffer, size_t nSize);
+  ~CH264NALUnescape();
+  const BYTE *GetBuffer() const { return m_pBuffer; }
+  size_t GetSize() const { return m_nSize; }
+
+private:
+  BYTE  *m_pBuffer = nullptr;
+  size_t m_nSize   = 0;
+};