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/*
* Copyright (C) 2010-2013 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.
*/
#include "stdafx.h"
#include "ExtradataParser.h"
#define MARKER if(BitRead(1) != 1) {ASSERT(0); return 0;}
CExtradataParser::CExtradataParser(BYTE *pExtradata, size_t extra_len)
: CByteParser(pExtradata, extra_len)
{
}
CExtradataParser::~CExtradataParser()
{
}
bool CExtradataParser::NextMPEGStartCode(BYTE &code)
{
BitByteAlign();
DWORD dw = (DWORD)-1;
do
{
if(!Remaining()) return false;
dw = (dw << 8) | (BYTE)BitRead(8);
}
while((dw&0xffffff00) != 0x00000100);
code = (BYTE)(dw&0xff);
return true;
}
size_t CExtradataParser::ParseMPEGSequenceHeader(BYTE *pTarget)
{
BYTE id = 0;
while(Remaining() && id != 0xb3) {
if(!NextMPEGStartCode(id)) {
return 0;
}
}
if(id != 0xb3) {
return 0;
}
size_t shpos = Pos() - 4;
BitRead(12); // Width
BitRead(12); // Height
BitRead(4); // AR
BitRead(4); // FPS
BitRead(18); // Bitrate
MARKER;
BitRead(10); // VBV
BitRead(1); // Constrained Flag
// intra quantisizer matrix
if(BitRead(1)) {
for (uint8_t i = 0; i < 64; i++) {
BitRead(8);
}
}
// non-intra quantisizer matrix
if(BitRead(1)) {
for (uint8_t i = 0; i < 64; i++) {
BitRead(8);
}
}
size_t shlen = Pos() - shpos;
size_t shextpos = 0;
size_t shextlen = 0;
if(NextMPEGStartCode(id) && id == 0xb5) { // sequence header ext
shextpos = Pos() - 4;
int startcode = BitRead(4); // Start Code Id; TODO: DIfferent start code ids mean different length of da2a
ASSERT(startcode == 1);
BitRead(1); // Profile Level Escape
BitRead(3); // Profile
BitRead(4); // Level
BitRead(1); // Progressive
BitRead(2); // Chroma
BitRead(2); // Width Extension
BitRead(2); // Height Extension
BitRead(12); // Bitrate Extension
MARKER;
BitRead(8); // VBV Buffer Size Extension
BitRead(1); // Low Delay
BitRead(2); // FPS Extension n
BitRead(5); // FPS Extension d
shextlen = Pos() - shextpos;
}
memcpy(pTarget, Start()+shpos, shlen);
if (shextpos) {
memcpy(pTarget+shlen, Start()+shextpos, shextlen);
}
return shlen + shextlen;
}
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