HEVC Test Model (HM)  HM-16.3
NALwrite.cpp
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33 
34 #include <vector>
35 #include <algorithm>
36 #include <ostream>
37 
38 #include "TLibCommon/NAL.h"
40 #include "NALwrite.h"
41 
42 using namespace std;
43 
46 
48 
49 Void writeNalUnitHeader(ostream& out, OutputNALUnit& nalu) // nal_unit_header()
50 {
51 TComOutputBitstream bsNALUHeader;
52 
53  bsNALUHeader.write(0,1); // forbidden_zero_bit
54  bsNALUHeader.write(nalu.m_nalUnitType, 6); // nal_unit_type
55  bsNALUHeader.write(nalu.m_nuhLayerId, 6); // nuh_layer_id
56  bsNALUHeader.write(nalu.m_temporalId+1, 3); // nuh_temporal_id_plus1
57 
58  out.write(bsNALUHeader.getByteStream(), bsNALUHeader.getByteStreamLength());
59 }
64 Void write(ostream& out, OutputNALUnit& nalu)
65 {
66  writeNalUnitHeader(out, nalu);
67  /* write out rsbp_byte's, inserting any required
68  * emulation_prevention_three_byte's */
69  /* 7.4.1 ...
70  * emulation_prevention_three_byte is a byte equal to 0x03. When an
71  * emulation_prevention_three_byte is present in the NAL unit, it shall be
72  * discarded by the decoding process.
73  * The last byte of the NAL unit shall not be equal to 0x00.
74  * Within the NAL unit, the following three-byte sequences shall not occur at
75  * any byte-aligned position:
76  * - 0x000000
77  * - 0x000001
78  * - 0x000002
79  * Within the NAL unit, any four-byte sequence that starts with 0x000003
80  * other than the following sequences shall not occur at any byte-aligned
81  * position:
82  * - 0x00000300
83  * - 0x00000301
84  * - 0x00000302
85  * - 0x00000303
86  */
87  vector<uint8_t>& rbsp = nalu.m_Bitstream.getFIFO();
88 
89  vector<uint8_t> outputBuffer;
90  outputBuffer.resize(rbsp.size()*2+1); //there can never be enough emulation_prevention_three_bytes to require this much space
91  std::size_t outputAmount = 0;
92  Int zeroCount = 0;
93  for (vector<uint8_t>::iterator it = rbsp.begin(); it != rbsp.end(); it++)
94  {
95  const uint8_t v=(*it);
96  if (zeroCount==2 && v<=3)
97  {
98  outputBuffer[outputAmount++]=emulation_prevention_three_byte[0];
99  zeroCount=0;
100  }
101 
102  if (v==0)
103  {
104  zeroCount++;
105  }
106  else
107  {
108  zeroCount=0;
109  }
110  outputBuffer[outputAmount++]=v;
111  }
112 
113  /* 7.4.1.1
114  * ... when the last byte of the RBSP data is equal to 0x00 (which can
115  * only occur when the RBSP ends in a cabac_zero_word), a final byte equal
116  * to 0x03 is appended to the end of the data.
117  */
118  if (zeroCount>0)
119  {
120  outputBuffer[outputAmount++]=emulation_prevention_three_byte[0];
121  }
122  out.write((Char*)&(*outputBuffer.begin()), outputAmount);
123 }
124 
129 {
130  bs.write( 1, 1 );
131  bs.writeAlignZero();
132 }
133 
static const Char emulation_prevention_three_byte[]
Definition: NALwrite.cpp:47
Void write(ostream &out, OutputNALUnit &nalu)
Definition: NALwrite.cpp:64
void Void
Definition: TypeDef.h:285
char Char
Definition: TypeDef.h:291
NalUnitType m_nalUnitType
nal_unit_type
Definition: NAL.h:49
STL namespace.
std::vector< uint8_t > & getFIFO()
Void writeNalUnitHeader(ostream &out, OutputNALUnit &nalu)
Definition: NALwrite.cpp:49
Char * getByteStream() const
class for handling bitstream (header)
UInt m_nuhLayerId
nuh_layer_id
Definition: NAL.h:51
int Int
Definition: TypeDef.h:296
Void write(UInt uiBits, UInt uiNumberOfBits)
UInt m_temporalId
temporal_id
Definition: NAL.h:50
TComOutputBitstream m_Bitstream
Definition: NALwrite.h:74
Void writeRBSPTrailingBits(TComOutputBitstream &bs)
Definition: NALwrite.cpp:128