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/*
* Copyright (C) 2010-2015 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 "MPEG2HeaderParser.h"
#pragma warning( push )
#pragma warning( disable : 4018 )
#pragma warning( disable : 4244 )
#define AVCODEC_X86_MATHOPS_H
#include "libavcodec/get_bits.h"
#pragma warning( pop )
#define SEQ_START_CODE 0x000001b3
#define EXT_START_CODE 0x000001b5
static inline const uint8_t* find_next_marker(const uint8_t *src, const uint8_t *end)
{
uint32_t mrk = 0xFFFFFFFF;
if(end-src < 4) return end;
while(src < end){
mrk = (mrk << 8) | *src++;
if((mrk & ~0xFF) == 0x00000100)
return src-4;
}
return end;
}
CMPEG2HeaderParser::CMPEG2HeaderParser(const BYTE *pData, size_t length)
{
memset(&hdr, 0, sizeof(hdr));
ParseMPEG2Header(pData, length);
}
CMPEG2HeaderParser::~CMPEG2HeaderParser(void)
{
}
void CMPEG2HeaderParser::ParseMPEG2Header(const BYTE *pData, size_t length)
{
if (length < 16)
return;
GetBitContext gb;
const uint8_t *start = pData;
const uint8_t *end = start + length;
const uint8_t *next = nullptr;
int size;
start = find_next_marker(start, end);
next = start;
for(; next < end; start = next) {
next = find_next_marker(start + 4, end);
size = (int)(next - start - 4);
if(size <= 0) continue;
init_get_bits(&gb, start + 4, (size - 4) * 8);
switch(AV_RB32(start)) {
case SEQ_START_CODE:
MPEG2ParseSequenceHeader(&gb);
break;
case EXT_START_CODE:
MPEG2ParseExtHeader(&gb);
break;
}
}
}
void CMPEG2HeaderParser::MPEG2ParseSequenceHeader(GetBitContext *gb)
{
}
void CMPEG2HeaderParser::MPEG2ParseExtHeader(GetBitContext *gb)
{
int startcode = get_bits(gb, 4); // Start Code
if (startcode == 1) {
hdr.valid = 1;
skip_bits(gb, 1); // profile and level esc
hdr.profile = get_bits(gb, 3);
hdr.level = get_bits(gb, 4);
hdr.interlaced = !get_bits1(gb);
hdr.chroma = get_bits(gb, 2);
// TODO: Fill in other fields, if needed
}
}
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