Void writeNalUnitHeader(ostream& out, OutputNALUnit& nalu) // nal_unit_header()
{
TComOutputBitstream bsNALUHeader;
bsNALUHeader.write(0,1); // forbidden_zero_bit
bsNALUHeader.write(nalu.m_nalUnitType, 6); // nal_unit_type
bsNALUHeader.write(nalu.m_reservedZero6Bits, 6); // nuh_reserved_zero_6bits
bsNALUHeader.write(nalu.m_temporalId+1, 3); // nuh_temporal_id_plus1
out.write(bsNALUHeader.getByteStream(), bsNALUHeader.getByteStreamLength());
}
Void writeNalUnitHeader(ostream& out, OutputNALUnit& nalu) // nal_unit_header()
{
TComOutputBitstream bsNALUHeader;
bsNALUHeader.write(0,1); // forbidden_zero_bit
bsNALUHeader.write(nalu.m_nalUnitType, 6); // nal_unit_type
bsNALUHeader.write(nalu.m_nuhLayerId, 6); // nuh_layer_id
bsNALUHeader.write(nalu.m_temporalId+1, 3); // nuh_temporal_id_plus1
out.write(reinterpret_cast<const TChar*>(bsNALUHeader.getByteStream()), bsNALUHeader.getByteStreamLength());
}
/**
* Write rbsp_trailing_bits to bs causing it to become byte-aligned
*/
Void writeRBSPTrailingBits(TComOutputBitstream& bs)
{
bs.write( 1, 1 );
bs.writeAlignZero();
}
/**
* write nalu to bytestream out, performing RBSP anti startcode
* emulation as required. nalu.m_RBSPayload must be byte aligned.
*/
void write(ostream& out, OutputNALUnit& nalu)
{
#if NAL_UNIT_HEADER
writeNalUnitHeader(out, nalu);
#else
TComOutputBitstream bsNALUHeader;
bsNALUHeader.write(0,1); // forbidden_zero_flag
#if !REMOVE_NAL_REF_FLAG
bsNALUHeader.write(nalu.m_nalRefFlag? 1 : 0, 1); // nal_ref_flag
#endif
bsNALUHeader.write(nalu.m_nalUnitType, 6); // nal_unit_type
#if REMOVE_NAL_REF_FLAG
bsNALUHeader.write(0, 6); // reserved_one_5bits
#endif
#if TEMPORAL_ID_PLUS1
bsNALUHeader.write(nalu.m_temporalId+1, 3); // temporal_id_plus1
#if !REMOVE_NAL_REF_FLAG
bsNALUHeader.write(0, 5); // reserved_one_5bits
#endif
#else
bsNALUHeader.write(nalu.m_temporalId, 3); // temporal_id
bsNALUHeader.write(1, 5); // reserved_one_5bits
#endif
out.write(bsNALUHeader.getByteStream(), bsNALUHeader.getByteStreamLength());
#endif
/* write out rsbp_byte's, inserting any required
* emulation_prevention_three_byte's */
/* 7.4.1 ...
* emulation_prevention_three_byte is a byte equal to 0x03. When an
* emulation_prevention_three_byte is present in the NAL unit, it shall be
* discarded by the decoding process.
* The last byte of the NAL unit shall not be equal to 0x00.
* Within the NAL unit, the following three-byte sequences shall not occur at
* any byte-aligned position:
* - 0x000000
* - 0x000001
* - 0x000002
* Within the NAL unit, any four-byte sequence that starts with 0x000003
* other than the following sequences shall not occur at any byte-aligned
* position:
* - 0x00000300
* - 0x00000301
* - 0x00000302
* - 0x00000303
*/
vector<uint8_t>& rbsp = nalu.m_Bitstream.getFIFO();
for (vector<uint8_t>::iterator it = rbsp.begin(); it != rbsp.end();)
{
/* 1) find the next emulated 00 00 {00,01,02,03}
* 2a) if not found, write all remaining bytes out, stop.
* 2b) otherwise, write all non-emulated bytes out
* 3) insert emulation_prevention_three_byte
*/
vector<uint8_t>::iterator found = it;
do
{
/* NB, end()-1, prevents finding a trailing two byte sequence */
found = search_n(found, rbsp.end()-1, 2, 0);
found++;
/* if not found, found == end, otherwise found = second zero byte */
if (found == rbsp.end())
break;
if (*(++found) <= 3)
break;
} while (true);
it = found;
if (found != rbsp.end())
{
it = rbsp.insert(found, emulation_prevention_three_byte[0]);
}
}
out.write((char*)&(*rbsp.begin()), rbsp.end() - rbsp.begin());
/* 7.4.1.1
* ... when the last byte of the RBSP data is equal to 0x00 (which can
* only occur when the RBSP ends in a cabac_zero_word), a final byte equal
* to 0x03 is appended to the end of the data.
*/
if (rbsp.back() == 0x00)
{
out.write(emulation_prevention_three_byte, 1);
}
}
