# Dirac - A Video Codec

Created by the British Broadcasting Corporation.

parseunit_byteio.h
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1/* ***** BEGIN LICENSE BLOCK *****
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3* $Id: parseunit_byteio.h,v 1.11 2008/05/02 05:57:19 asuraparaju Exp $ $Name: Dirac_1_0_2 $
4*
5* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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7* The contents of this file are subject to the Mozilla Public License
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16* The Original Code is BBC Research and Development code.
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24* Anuradha Suraparaju
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38
42#ifndef parseunit_byteio_h
43#define parseunit_byteio_h
44
45//SYSTEM INLUDES
46#include <map> // Byte-map
47#include <string> // stores values
48
49//LOCAL INCLUDES
50#include "byteio.h" // Parent class
51
52
53 namespace dirac
54{
55
56 /* Types of parse-unit */
57 typedef enum {
58 PU_SEQ_HEADER=0,
59 PU_PICTURE,
60 PU_END_OF_SEQUENCE,
61 PU_AUXILIARY_DATA,
62 PU_PADDING_DATA,
63 PU_CORE_PICTURE,
64 PU_LOW_DELAY_PICTURE,
65 PU_UNDEFINED
66 } ParseUnitType;
67
72 class ParseUnitByteIO : public ByteIO
73 {
74 public:
75
79 ParseUnitByteIO();
80
85 ParseUnitByteIO(const ByteIO& byte_io);
86
91 ParseUnitByteIO(const ParseUnitByteIO& parseunit_byteio);
92
96 ~ParseUnitByteIO();
97
102 virtual void CollateByteStats(DiracByteStats& dirac_byte_stats);
103
108 bool Input(); // decoding
109
113 bool IsValid();
114
119 bool CanSkip();
120
124 virtual const std::string GetBytes(); // encoding
125
130 void SetAdjacentParseUnits(ParseUnitByteIO *p_prev_parseunit); // encoding
131
132 /*
133 * Gets number of bytes input/output within unit
134 */
135 virtual int GetSize() const;
136
140 int GetNextParseOffset() const;
141
145 int GetPreviousParseOffset() const;
146
150 virtual ParseUnitType GetType() const;
151
155 bool IsSeqHeader() const
156 { return m_parse_code==0x00; }
157
161 bool IsEndOfSequence() const
162 { return m_parse_code==0x10; }
163
167 bool IsAuxiliaryData() const
168 { return (m_parse_code&0xF8)==0x20; }
169
173 bool IsPaddingData() const
174 { return m_parse_code==0x30; }
175
179 bool IsPicture() const
180 { return ((m_parse_code&0x08)==0x08); }
181
185 bool IsLowDelay() const
186 { return ((m_parse_code&0x88)==0x88); }
187
191 bool IsCoreSyntax() const
192 { return ((m_parse_code&0x88)==0x08); }
193
197 bool IsUsingAC() const
198 { return ((m_parse_code&0x48)==0x08); }
199
200 protected:
201
206 virtual int CalcNextUnitOffset();
207
212 virtual unsigned char CalcParseCode() const { return 0;} // encoding
213
218 bool SyncToUnitStart(); // decoding
219
223 unsigned char GetParseCode() const { return m_parse_code;}
224
225 private:
226
230 int m_previous_parse_offset;
231
235 int m_next_parse_offset;
236
240 unsigned char m_parse_code;
241
242 };
243
244
245} // namespace dirac
246
247#endif
byteio.h
dirac
Definition of class SequenceHeaderByteIO.
Definition: accessunit_byteio.h:52
dirac::ParseUnitType
ParseUnitType
Definition: parseunit_byteio.h:57
dirac::PU_UNDEFINED
@ PU_UNDEFINED
Definition: parseunit_byteio.h:65
dirac::PU_END_OF_SEQUENCE
@ PU_END_OF_SEQUENCE
Definition: parseunit_byteio.h:60
dirac::PU_CORE_PICTURE
@ PU_CORE_PICTURE
Definition: parseunit_byteio.h:63
dirac::PU_AUXILIARY_DATA
@ PU_AUXILIARY_DATA
Definition: parseunit_byteio.h:61
dirac::PU_SEQ_HEADER
@ PU_SEQ_HEADER
Definition: parseunit_byteio.h:58
dirac::PU_PADDING_DATA
@ PU_PADDING_DATA
Definition: parseunit_byteio.h:62
dirac::PU_PICTURE
@ PU_PICTURE
Definition: parseunit_byteio.h:59
dirac::PU_LOW_DELAY_PICTURE
@ PU_LOW_DELAY_PICTURE
Definition: parseunit_byteio.h:64
dirac::ByteIO
Class ByteIO - top-level class for reading/writing bytes to a stream.
Definition: byteio.h:73
dirac::DiracByteStats
Class DiracByteStats - for collecting statistics on aspects of the Dirac byte-stream.
Definition: dirac_byte_stats.h:71
dirac::ParseUnitByteIO
Represents a collection of data in a Dirac bytestream that can be parsed as a self-contained unit.
Definition: parseunit_byteio.h:73
dirac::ParseUnitByteIO::IsAuxiliaryData
bool IsAuxiliaryData() const
Returns true is parse unit is Auxiliary Data.
Definition: parseunit_byteio.h:167
dirac::ParseUnitByteIO::m_previous_parse_offset
int m_previous_parse_offset
Number of bytes to next parse-unit.
Definition: parseunit_byteio.h:230
dirac::ParseUnitByteIO::ParseUnitByteIO
ParseUnitByteIO(const ByteIO &byte_io)
Constructor.
dirac::ParseUnitByteIO::SyncToUnitStart
bool SyncToUnitStart()
Locates start of parse-unit.
dirac::ParseUnitByteIO::IsLowDelay
bool IsLowDelay() const
Returns true is parse unit is Low Delay Sybtax unit.
Definition: parseunit_byteio.h:185
dirac::ParseUnitByteIO::CollateByteStats
virtual void CollateByteStats(DiracByteStats &dirac_byte_stats)
Gathers byte stats on the parse-unit data.
dirac::ParseUnitByteIO::GetBytes
virtual const std::string GetBytes()
Gets string containing coded bytes.
dirac::ParseUnitByteIO::IsEndOfSequence
bool IsEndOfSequence() const
Returns true is parse unit is an End of Sequence unit.
Definition: parseunit_byteio.h:161
dirac::ParseUnitByteIO::m_parse_code
unsigned char m_parse_code
Parse-type-identifier.
Definition: parseunit_byteio.h:240
dirac::ParseUnitByteIO::CanSkip
bool CanSkip()
Can Skip past the entire parse-unit.
dirac::ParseUnitByteIO::ParseUnitByteIO
ParseUnitByteIO(const ParseUnitByteIO &parseunit_byteio)
Constructor.
dirac::ParseUnitByteIO::IsCoreSyntax
bool IsCoreSyntax() const
Returns true is parse unit is Core syntax unit.
Definition: parseunit_byteio.h:191
dirac::ParseUnitByteIO::CalcParseCode
virtual unsigned char CalcParseCode() const
Pure virtual method for calculating parse-code.
Definition: parseunit_byteio.h:212
dirac::ParseUnitByteIO::GetSize
virtual int GetSize() const
Gets size (in bytes)
dirac::ParseUnitByteIO::CalcNextUnitOffset
virtual int CalcNextUnitOffset()
Calculates number of bytes to start of next unit.
dirac::ParseUnitByteIO::IsSeqHeader
bool IsSeqHeader() const
Returns true is parse unit is a Sequence Header.
Definition: parseunit_byteio.h:155
dirac::ParseUnitByteIO::GetParseCode
unsigned char GetParseCode() const
Get parse code.
Definition: parseunit_byteio.h:223
dirac::ParseUnitByteIO::SetAdjacentParseUnits
void SetAdjacentParseUnits(ParseUnitByteIO *p_prev_parseunit)
Set next/previous parse-unit values.
dirac::ParseUnitByteIO::~ParseUnitByteIO
~ParseUnitByteIO()
Destructor.
dirac::ParseUnitByteIO::GetPreviousParseOffset
int GetPreviousParseOffset() const
Gets number of bytes to start of previous parse-unit.
dirac::ParseUnitByteIO::m_next_parse_offset
int m_next_parse_offset
Number of bytes to previous parse-unit.
Definition: parseunit_byteio.h:235
dirac::ParseUnitByteIO::IsUsingAC
bool IsUsingAC() const
Returns true is parse unit uses Arithmetic coding.
Definition: parseunit_byteio.h:197
dirac::ParseUnitByteIO::GetNextParseOffset
int GetNextParseOffset() const
Gets expected number of bytes to start of next parse-unit.
dirac::ParseUnitByteIO::GetType
virtual ParseUnitType GetType() const
Gets parse-unit type.
dirac::ParseUnitByteIO::Input
bool Input()
Reads from byte-stream to find parse data.
dirac::ParseUnitByteIO::IsPicture
bool IsPicture() const
Returns true is parse unit is Picture data.
Definition: parseunit_byteio.h:179
dirac::ParseUnitByteIO::IsPaddingData
bool IsPaddingData() const
Returns true is parse unit is Padding data.
Definition: parseunit_byteio.h:173
dirac::ParseUnitByteIO::IsValid
bool IsValid()
Accesses validity of a unit by comparing it with an adjacent unit.
dirac::ParseUnitByteIO::ParseUnitByteIO
ParseUnitByteIO()
Constructor.

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