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|
/*****************************************************************
|
| AP4 - AC-3 Sync Frame Parser
|
| Copyright 2002-2020 Axiomatic Systems, LLC
|
|
| This file is part of Bento4/AP4 (MP4 Atom Processing Library).
|
| Unless you have obtained Bento4 under a difference license,
| this version of Bento4 is Bento4|GPL.
| Bento4|GPL 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, or (at your option)
| any later version.
|
| Bento4|GPL 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 Bento4|GPL; see the file COPYING. If not, write to the
| Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
| 02111-1307, USA.
|
****************************************************************/
#ifndef _AP4_AC3_PARSER_H_
#define _AP4_AC3_PARSER_H_
/*----------------------------------------------------------------------
| includes
+---------------------------------------------------------------------*/
#include "Ap4Types.h"
#include "Ap4BitStream.h"
#include "Ap4Dac3Atom.h"
#include "Ap4Eac3Parser.h"
/*----------------------------------------------------------------------
| constants
+---------------------------------------------------------------------*/
#define AP4_AC3_HEADER_SIZE 32 /* The header size for AC-3 parser, syncinfo() + bsi() */
#define AP4_AC3_SYNC_WORD_BIG_ENDIAN 0x0B77 /* Big endian, 16 sync bits */
#define AP4_AC3_SYNC_WORD_LITTLE_ENDIAN 0x770B /* Little endian, 16 sync bits */
const AP4_UI32 FRAME_SIZE_CODE_ARY_AC3[3][38] = {
{64,64,80,80,96,96,112,112,128,128,160,160,192,192,224,224,256,256,320,320,384,384,448,448,512,512,640,640,768,768,896,896,1024,1024,1152,1152,1280,1280},
{69,70,87,88,104,105,121,122,139,140,174,175,208,209,243,244,278,279,348,349,417,418,487,488,557,558696,697,835,836,976,977,1114,1115,1253,1254,1393,1394},
{96,96,120,120,144,144,168,168,192,192,240,240,288,288,336,336,384,384,480,480,576,576,672,672,768,768,960,960,1152,1152,1344,1344,1536,1536,1728,1728,1920,1920}};
const AP4_UI32 FSCOD_AC3[4] = {48000, 44100, 32000, 0};
/*----------------------------------------------------------------------
| types
+---------------------------------------------------------------------*/
class AP4_Ac3Header {
public:
// constructor
AP4_Ac3Header(const AP4_UI08* bytes);
// methods
AP4_Result Check();
AP4_UI32 m_HeadSize;
AP4_UI32 m_FrameSize;
AP4_UI32 m_ChannelCount;
// AC-3 sysninfo()
AP4_UI32 m_Fscod;
AP4_UI32 m_Frmsizecod;
// AC-3 bsi()
AP4_UI32 m_Bsid;
AP4_UI32 m_Bsmod;
AP4_UI32 m_Acmod;
AP4_UI32 m_Lfeon;
AP4_UI32 m_Addbsie;
AP4_UI32 m_Addbsil; // 6 bits
AP4_UI08 m_addbsi[65]; // (addbsil+1)×8
// class methods
static bool MatchFixed(AP4_Ac3Header& frame, AP4_Ac3Header& next_frame);
};
typedef struct {
AP4_UI32 m_ChannelCount;
AP4_UI32 m_FrameSize;
AP4_UI32 m_SampleRate;
AP4_Dac3Atom::StreamInfo m_Ac3StreamInfo;
} AP4_Ac3FrameInfo;
typedef struct {
AP4_BitStream* m_Source;
AP4_Ac3FrameInfo m_Info;
AP4_Flags m_LittleEndian;
} AP4_Ac3Frame;
class AP4_Ac3Parser {
public:
// constructor and destructor
AP4_Ac3Parser();
virtual ~AP4_Ac3Parser();
// methods
AP4_Result Reset();
AP4_Result Feed(const AP4_UI08* buffer,
AP4_Size* buffer_size,
AP4_Flags flags = 0);
AP4_Result FindFrame(AP4_Ac3Frame& frame);
AP4_Result Skip(AP4_Size size);
AP4_Size GetBytesFree();
AP4_Size GetBytesAvailable();
private:
// methods
AP4_Result FindHeader(AP4_UI08* header);
// members
AP4_BitStream m_Bits;
AP4_Cardinal m_FrameCount;
AP4_Flags m_LittleEndian;
};
#endif // _AP4_AC3_PARSER_H_
|
