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/*
* Copyright (C) 2010-2014 Hendrik Leppkes
* http://www.1f0.de
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Initial design and concept by Gabest and the MPC-HC Team, copyright under GPLv2
*/
#include "stdafx.h"
#include "H264Nalu.h"
void CH264Nalu::SetBuffer(const BYTE* pBuffer, size_t nSize, int nNALSize)
{
m_pBuffer = pBuffer;
m_nSize = nSize;
m_nNALSize = nNALSize;
m_nCurPos = 0;
m_nNextRTP = 0;
m_nNALStartPos = 0;
m_nNALDataPos = 0;
// In AnnexB, the buffer is not guaranteed to start on a NAL boundary
if (nNALSize == 0 && nSize > 0)
MoveToNextAnnexBStartcode();
}
bool CH264Nalu::MoveToNextAnnexBStartcode()
{
if (m_nSize < 4)
goto notfound;
size_t nBuffEnd = m_nSize - 4;
for (size_t i = m_nCurPos; i <= nBuffEnd; i++) {
if ((*((DWORD*)(m_pBuffer+i)) & 0x00FFFFFF) == 0x00010000) {
// Found next AnnexB NAL
m_nCurPos = i;
return true;
}
}
notfound:
m_nCurPos = m_nSize;
return false;
}
bool CH264Nalu::MoveToNextRTPStartcode()
{
if (m_nNextRTP < m_nSize) {
m_nCurPos = m_nNextRTP;
return true;
}
m_nCurPos = m_nSize;
return false;
}
bool CH264Nalu::ReadNext()
{
if (m_nCurPos >= m_nSize) return false;
if ((m_nNALSize != 0) && (m_nCurPos == m_nNextRTP)) {
if (m_nCurPos + m_nNALSize >= m_nSize) return false;
// RTP Nalu type : (XX XX) XX XX NAL..., with XX XX XX XX or XX XX equal to NAL size
m_nNALStartPos = m_nCurPos;
m_nNALDataPos = m_nCurPos + m_nNALSize;
// Read Length code from the buffer
unsigned nTemp = 0;
for (int i = 0; i < m_nNALSize; i++)
nTemp = (nTemp << 8) + m_pBuffer[m_nCurPos++];
m_nNextRTP += nTemp + m_nNALSize;
MoveToNextRTPStartcode();
} else {
// Remove trailing bits
while (m_pBuffer[m_nCurPos] == 0x00 && ((*((DWORD*)(m_pBuffer+m_nCurPos)) & 0x00FFFFFF) != 0x00010000))
m_nCurPos++;
// AnnexB Nalu : 00 00 01 NAL...
m_nNALStartPos = m_nCurPos;
m_nCurPos += 3;
m_nNALDataPos = m_nCurPos;
MoveToNextAnnexBStartcode();
}
forbidden_bit = (m_pBuffer[m_nNALDataPos]>>7) & 1;
nal_reference_idc = (m_pBuffer[m_nNALDataPos]>>5) & 3;
nal_unit_type = (NALU_TYPE) (m_pBuffer[m_nNALDataPos] & 0x1f);
return true;
}
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