wheee!

1 files changed, 267 insertions, 0 deletions

diff --git a/src/MPEG.cpp b/src/MPEG.cpp
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+++ b/src/MPEG.cpp
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+/*
+Copyright (c) 2005, John Hurst
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+3. The name of the author may not be used to endorse or promote products
+   derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+/*! \file    MPEG.cpp
+    \version $Id$
+    \brief   MPEG2 VES parser
+*/
+
+#include <MPEG.h>
+
+// walk a buffer stopping at the end of the buffer or the end of a VES
+// start code '00 00 01'.  If successful, returns address of first byte
+// of start code
+ASDCP::Result_t
+ASDCP::MPEG2::FindVESStartCode(const byte_t* buf, ui32_t buf_len, StartCode_t* sc, const byte_t** new_pos)
+{
+  ASDCP_TEST_NULL(buf);
+  ASDCP_TEST_NULL(new_pos);
+
+  ui32_t zero_i = 0;
+  const byte_t* p = buf;
+  const byte_t* end_p = buf + buf_len;
+
+  for ( ; p < end_p; p++ )
+    {
+      if ( *p == 0 )
+	zero_i++;
+
+      else if ( *p == 1 && zero_i > 1 )
+	{
+	  // 2 or more 0 bytes followed by a 1, start code is next
+	  if ( ++p == end_p )
+	    return RESULT_FAIL;
+
+	  *new_pos = p - 3;
+	  *sc = (StartCode_t)*p;
+	  return RESULT_OK;
+	}
+      else
+	zero_i = 0;
+    }
+
+  *new_pos = buf + buf_len;
+  return  RESULT_FAIL;
+}
+
+
+//------------------------------------------------------------------------------------------
+
+//
+ASDCP::Rational
+ASDCP::MPEG2::Accessor::Sequence::AspectRatio()
+{
+  switch ( m_p[3] & 0xf0 )
+    {
+    case 0x10: return Rational(1,1);
+    case 0x20: return Rational(4,3);
+    case 0x30: return Rational(16,9);
+    case 0x40: return Rational(221,100);
+    }
+
+  DefaultLogSink().Error("Unknown AspectRatio value: %02x\n", m_p[3]);
+  return Rational(0,0);
+}
+
+//------------------------------------------------------------------------------------------
+
+enum State_t {
+    ST_IDLE,
+    ST_START_HEADER,
+    ST_IN_HEADER,
+};
+
+
+//
+class ASDCP::MPEG2::VESParser::h__StreamState
+{
+public:
+  State_t m_State;
+  h__StreamState() : m_State(ST_IDLE) {}
+  ~h__StreamState() {}
+
+  void Goto_START_HEADER() {    m_State = ST_START_HEADER;  }
+  void Goto_IN_HEADER()    {    m_State = ST_IN_HEADER;  }
+  void Goto_IDLE()         {    m_State = ST_IDLE;  }
+  bool Test_IDLE()         { return m_State == ST_IDLE; }
+  bool Test_START_HEADER() { return m_State == ST_START_HEADER; }
+  bool Test_IN_HEADER()    { return m_State == ST_IN_HEADER; }
+};
+
+//------------------------------------------------------------------------------------------
+
+
+ASDCP::MPEG2::VESParser::VESParser() :
+  m_Delegate(0), m_HBufLen(0), m_ZeroCount(0), m_Partial(false)
+{
+  m_State = new h__StreamState;
+}
+
+ASDCP::MPEG2::VESParser::~VESParser()
+{
+}
+
+
+//
+void
+ASDCP::MPEG2::VESParser::SetDelegate(VESParserDelegate* Delegate)
+{
+  m_Delegate = Delegate;
+}
+
+//
+void
+ASDCP::MPEG2::VESParser::Reset()
+{
+  m_State->Goto_IDLE();
+  m_HBufLen = 0;
+  m_ZeroCount = 0;
+  m_Partial = false;
+}
+
+//
+ASDCP::Result_t
+ASDCP::MPEG2::VESParser::Parse(const byte_t* buf, ui32_t buf_len)
+{
+  ASDCP_TEST_NULL(buf);
+  ASDCP_TEST_NULL(m_Delegate);
+
+  Result_t result;
+  const byte_t* end_p = buf + buf_len;
+  const byte_t* run_pos = buf; // track runs of uninteresting data as a position and count
+  ui32_t  run_len = 0;
+
+  // search for MPEG2 headers
+  // copy interesting data to a buffer and pass to delegate for processing
+  for ( const byte_t* p = buf; p < end_p; p++ )
+    {
+      if ( m_State->Test_IN_HEADER() )
+	{
+	  m_HBuf[m_HBufLen++] = *p;
+	  assert(m_HBufLen < VESHeaderBufSize);
+	}
+      else
+	{
+	  run_len++;
+	}
+
+      if ( m_State->Test_START_HEADER() ) // *p is a start code
+	{
+	  // Do we already have a header? We need to flush it...
+	  if ( m_HBufLen > 0)
+	    {
+	      m_HBufLen -= 3; // remove the current partial start code
+
+	      // let the delegate handle the header
+	      switch( m_HBuf[3] )
+		{
+		case PIC_START:   result = m_Delegate->Picture(this, m_HBuf, m_HBufLen);   break;	  
+		case EXT_START:   result = m_Delegate->Extension(this, m_HBuf, m_HBufLen); break;
+		case SEQ_START:   result = m_Delegate->Sequence(this, m_HBuf, m_HBufLen);  break;
+		case GOP_START:   result = m_Delegate->GOP(this, m_HBuf, m_HBufLen);       break;
+
+		default:
+		  DefaultLogSink().Error("Unexpected start code: %02x at byte %lu\n",
+					 m_HBuf[3], (ui32_t)(p - buf));
+		  result = RESULT_RAW_FORMAT;
+		}
+
+	      // the next run starts with the start code that got us here
+	      run_len = 4;
+	      run_pos = p-3;
+	      m_HBufLen = 0;
+
+	      // Parser handlers return RESULT_FALSE to teriminate without error
+	      if ( result != RESULT_OK )
+		{
+		  m_State->Goto_IDLE();
+		  return result;
+		}
+	    }
+
+	  // all headers start with this same start code: 00 00 01 xx
+ 	  m_HBuf[0] = m_HBuf[1] = 0; m_HBuf[2] = 1; m_HBuf[3] = *p;
+
+	  // is this a header we want?
+	  if ( *p == PIC_START || *p == SEQ_START || *p == EXT_START || *p == GOP_START )
+	    {
+	      // we're starting a new header, flush the current run
+	      if ( run_len > 4 )
+		{
+		  m_Delegate->Data(this, run_pos, run_len - 4);
+		  run_len = 0;
+		}
+
+	      m_Partial = false;
+	      m_HBufLen = 4;
+	      m_State->Goto_IN_HEADER();
+	    }
+	  else
+	    {
+	      if ( *p == FIRST_SLICE )
+		result = m_Delegate->Slice(this);
+
+	      if ( m_Partial )
+		{
+		  m_Partial = false;
+		  m_Delegate->Data(this, m_HBuf, 3);
+		}
+	      
+	      m_State->Goto_IDLE();
+	    }
+	}
+      else if ( *p == 0 )
+	{
+	  m_ZeroCount++;
+	}
+      else
+	{
+	  if ( *p == 1 && m_ZeroCount > 1 )
+	    m_State->Goto_START_HEADER();
+
+	  m_ZeroCount = 0;
+	}
+    }
+
+  if ( run_len > 0 )
+    {
+      if ( m_State->Test_START_HEADER() )
+	{
+	  m_Partial = true; // 'partial' means we have a partial header in progress
+	  run_len -= 3;
+	}
+
+      // flush the current run
+      m_Delegate->Data(this, run_pos, run_len);
+    }
+
+  return RESULT_OK;
+}
+
+
+//
+// end MPEG.cpp
+//