1 files changed, 123 insertions, 0 deletions
diff --git a/Src/h264dec/ldecod/src/nal.c b/Src/h264dec/ldecod/src/nal.c
new file mode 100644
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+++ b/Src/h264dec/ldecod/src/nal.c
@@ -0,0 +1,123 @@
+
+/*!
+ ************************************************************************
+ * \file  nal.c
+ *
+ * \brief
+ *    Converts Encapsulated Byte Sequence Packets (EBSP) to Raw Byte
+ *    Sequence Packets (RBSP), and then onto String Of Data Bits (SODB)
+ *
+ * \author
+ *    Main contributors (see contributors.h for copyright, address and affiliation details)
+ *    - Shankar L. Regunathan <shanre@microsoft.com>
+ *    - Tobias Oelbaum <oelbaum@drehvial.de>
+************************************************************************
+ */
+
+#include "contributors.h"
+#include "global.h"
+
+ /*!
+ ************************************************************************
+ * \brief
+ *    Converts RBSP to string of data bits
+ * \param streamBuffer
+ *          pointer to buffer containing data
+ *  \param last_byte_pos
+ *          position of the last byte containing data.
+ * \return last_byte_pos
+ *          position of the last byte pos. If the last-byte was entirely a stuffing byte,
+ *          it is removed, and the last_byte_pos is updated.
+ *
+************************************************************************/
+
+int RBSPtoSODB(byte *streamBuffer, int last_byte_pos)
+{
+  int ctr_bit, bitoffset;
+
+  bitoffset = 0;
+  //find trailing 1
+  ctr_bit = (streamBuffer[last_byte_pos-1] & (0x01<<bitoffset));   // set up control bit
+
+  while (ctr_bit==0)
+  {                 // find trailing 1 bit
+    bitoffset++;
+    if(bitoffset == 8)
+    {
+      if(last_byte_pos == 0)
+        printf(" Panic: All zero data sequence in RBSP \n");
+      assert(last_byte_pos != 0);
+      last_byte_pos -= 1;
+      bitoffset = 0;
+    }
+    ctr_bit= streamBuffer[last_byte_pos-1] & (0x01<<(bitoffset));
+  }
+
+
+  // We keep the stop bit for now
+/*  if (remove_stop)
+  {
+    streamBuffer[last_byte_pos-1] -= (0x01<<(bitoffset));
+    if(bitoffset == 7)
+      return(last_byte_pos-1);
+    else
+      return(last_byte_pos);
+  }
+*/
+  return(last_byte_pos);
+
+}
+
+
+/*!
+************************************************************************
+* \brief
+*    Converts Encapsulated Byte Sequence Packets to RBSP
+* \param streamBuffer
+*    pointer to data stream
+* \param end_bytepos
+*    size of data stream
+* \param begin_bytepos
+*    Position after beginning
+************************************************************************/
+
+// TODO: benski> optimize using BitScanReverse
+int EBSPtoRBSP(byte *streamBuffer, int end_bytepos)
+{
+  int i, j, count;
+		int begin_bytepos = 1;
+  count = 0;
+
+
+  if(end_bytepos < begin_bytepos)
+    return end_bytepos;
+
+  j = begin_bytepos;
+
+  for(i = begin_bytepos; i < end_bytepos; i++)
+  { //starting from begin_bytepos to avoid header information
+    //in NAL unit, 0x000000, 0x000001 or 0x000002 shall not occur at any byte-aligned position
+    if(count == ZEROBYTES_SHORTSTARTCODE && streamBuffer[i] < 0x03) 
+      return j;//-1;
+    if(count == ZEROBYTES_SHORTSTARTCODE && streamBuffer[i] == 0x03)
+    {
+      //check the 4th byte after 0x000003, except when cabac_zero_word is used, in which case the last three bytes of this NAL unit must be 0x000003
+      if((i < end_bytepos-1) && (streamBuffer[i+1] > 0x03))
+        return -1;
+      //if cabac_zero_word is used, the final byte of this NAL unit(0x03) is discarded, and the last two bytes of RBSP must be 0x0000
+      if(i == end_bytepos-1)
+        return j;
+
+      i++;
+      count = 0;
+    }
+    streamBuffer[j] = streamBuffer[i];
+    if(streamBuffer[i] == 0x00)
+      count++;
+    else
+      count = 0;
+    j++;
+  }
+
+  return j;
+}