CEncoder_CMacroBlock - Man Page

A macro block is an encoding unit of fixed size (uncoded)

Synopsis

Public Member Functions

CMacroBlock (CEncoder *encoder)
void Init (int lastLevelIndex)
void BitplaneEncode ()

DataT m_value [BufferSize]
input buffer of values with index m_valuePos
UINT32 m_codeBuffer [CodeBufferLen]
output buffer for encoded bitstream
ROIBlockHeader m_header
block header
UINT32 m_valuePos
current buffer position
UINT32 m_maxAbsValue
maximum absolute coefficient in each buffer
UINT32 m_codePos
current position in encoded bitstream
int m_lastLevelIndex
index of last encoded level: [0, nLevels); used because a level-end can occur before a buffer is full

Private Member Functions

UINT32 RLESigns (UINT32 codePos, UINT32 *signBits, UINT32 signLen)
UINT32 DecomposeBitplane (UINT32 bufferSize, UINT32 planeMask, UINT32 codePos, UINT32 *sigBits, UINT32 *refBits, UINT32 *signBits, UINT32 &signLen, UINT32 &codeLen)
UINT8 NumberOfBitplanes ()
bool GetBitAtPos (UINT32 pos, UINT32 planeMask) const

Private Attributes

CEncoder * m_encoder
bool m_sigFlagVector [BufferSize+1]

Detailed Description

A macro block is an encoding unit of fixed size (uncoded)

PGF encoder macro block class.

Author: C. Stamm, I. Bauersachs

Definition at line 51 of file Encoder.h.

Constructor & Destructor Documentation

CEncoder::CMacroBlock::CMacroBlock (CEncoder * encoder) [inline]

Constructor: Initializes new macro block.

Parameters: encoder Pointer to outer class.

Definition at line 56 of file Encoder.h.

57                           : 4351 )
58                 : m_value()
59                 , m_codeBuffer()
60                 , m_header(0)
61                 , m_encoder(encoder)
62                 , m_sigFlagVector()
63                 {
64                         ASSERT(m_encoder);
65                         Init(-1);
66                 }

Member Function Documentation

void CEncoder::CMacroBlock::BitplaneEncode ()

Encodes this macro block into internal code buffer. Several macro blocks can be encoded in parallel. Call CEncoder::WriteMacroBlock after this method.

Definition at line 480 of file Encoder.cpp.

480                                          {
481         UINT8   nPlanes;
482         UINT32  sigLen, codeLen = 0, wordPos, refLen, signLen;
483         UINT32  sigBits[BufferLen] = { 0 }; 
484         UINT32  refBits[BufferLen] = { 0 }; 
485         UINT32  signBits[BufferLen] = { 0 }; 
486         UINT32  planeMask;
487         UINT32  bufferSize = m_header.rbh.bufferSize; ASSERT(bufferSize <= BufferSize);
488         bool    useRL;
489 
490 #ifdef TRACE
491         //printf("which thread: %d0, omp_get_thread_num());
492 #endif 
493 
494         // clear significance vector
495         for (UINT32 k=0; k < bufferSize; k++) {
496                 m_sigFlagVector[k] = false;
497         }
498         m_sigFlagVector[bufferSize] = true; // sentinel
499 
500         // clear output buffer
501         for (UINT32 k=0; k < bufferSize; k++) {
502                 m_codeBuffer[k] = 0;
503         }
504         m_codePos = 0;
505 
506         // compute number of bit planes and split buffer into separate bit planes
507         nPlanes = NumberOfBitplanes();
508 
509         // write number of bit planes to m_codeBuffer
510         // <nPlanes>
511         SetValueBlock(m_codeBuffer, 0, nPlanes, MaxBitPlanesLog);
512         m_codePos += MaxBitPlanesLog;
513 
514         // loop through all bit planes
515         if (nPlanes == 0) nPlanes = MaxBitPlanes + 1;
516         planeMask = 1 << (nPlanes - 1);
517 
518         for (int plane = nPlanes - 1; plane >= 0; plane--) {
519                 // clear significant bitset
520                 for (UINT32 k=0; k < BufferLen; k++) {
521                         sigBits[k] = 0;
522                 }
523 
524                 // split bitplane in significant bitset and refinement bitset
525                 sigLen = DecomposeBitplane(bufferSize, planeMask, m_codePos + RLblockSizeLen + 1, sigBits, refBits, signBits, signLen, codeLen);
526 
527                 if (sigLen > 0 && codeLen <= MaxCodeLen && codeLen < AlignWordPos(sigLen) + AlignWordPos(signLen) + 2*RLblockSizeLen) {
528                         // set RL code bit
529                         // <1><codeLen>
530                         SetBit(m_codeBuffer, m_codePos++);
531 
532                         // write length codeLen to m_codeBuffer
533                         SetValueBlock(m_codeBuffer, m_codePos, codeLen, RLblockSizeLen);
534                         m_codePos += RLblockSizeLen + codeLen;
535                 } else {
536                 #ifdef TRACE
537                         //printf("new0);
538                         //for (UINT32 i=0; i < bufferSize; i++) {
539                         //      printf("%s", (GetBit(sigBits, i)) ? "1" : "_");
540                         //      if (i%120 == 119) printf("0);
541                         //}
542                         //printf("0);
543                 #endif // TRACE
544 
545                         // run-length coding wasn't efficient enough
546                         // we don't use RL coding for sigBits
547                         // <0><sigLen>
548                         ClearBit(m_codeBuffer, m_codePos++);
549 
550                         // write length sigLen to m_codeBuffer
551                         ASSERT(sigLen <= MaxCodeLen); 
552                         SetValueBlock(m_codeBuffer, m_codePos, sigLen, RLblockSizeLen);
553                         m_codePos += RLblockSizeLen;
554 
555                         if (m_encoder->m_favorSpeed || signLen == 0) {
556                                 useRL = false;
557                         } else {
558                                 // overwrite m_codeBuffer
559                                 useRL = true;
560                                 // run-length encode m_sign and append them to the m_codeBuffer
561                                 codeLen = RLESigns(m_codePos + RLblockSizeLen + 1, signBits, signLen);
562                         }
563 
564                         if (useRL && codeLen <= MaxCodeLen && codeLen < signLen) {
565                                 // RL encoding of m_sign was efficient
566                                 // <1><codeLen><codedSignBits>_
567                                 // write RL code bit
568                                 SetBit(m_codeBuffer, m_codePos++);
569                                 
570                                 // write codeLen to m_codeBuffer
571                                 SetValueBlock(m_codeBuffer, m_codePos, codeLen, RLblockSizeLen);
572 
573                                 // compute position of sigBits
574                                 wordPos = NumberOfWords(m_codePos + RLblockSizeLen + codeLen);
575                                 ASSERT(0 <= wordPos && wordPos < CodeBufferLen);
576                         } else {
577                                 // RL encoding of signBits wasn't efficient
578                                 // <0><signLen>_<signBits>_
579                                 // clear RL code bit
580                                 ClearBit(m_codeBuffer, m_codePos++);
581 
582                                 // write signLen to m_codeBuffer
583                                 ASSERT(signLen <= MaxCodeLen); 
584                                 SetValueBlock(m_codeBuffer, m_codePos, signLen, RLblockSizeLen);
585 
586                                 // write signBits to m_codeBuffer
587                                 wordPos = NumberOfWords(m_codePos + RLblockSizeLen);
588                                 ASSERT(0 <= wordPos && wordPos < CodeBufferLen);
589                                 codeLen = NumberOfWords(signLen);
590 
591                                 for (UINT32 k=0; k < codeLen; k++) {
592                                         m_codeBuffer[wordPos++] = signBits[k];
593                                 }
594                         }
595 
596                         // write sigBits
597                         // <sigBits>_
598                         ASSERT(0 <= wordPos && wordPos < CodeBufferLen);
599                         refLen = NumberOfWords(sigLen);
600 
601                         for (UINT32 k=0; k < refLen; k++) {
602                                 m_codeBuffer[wordPos++] = sigBits[k];
603                         }
604                         m_codePos = wordPos << WordWidthLog;
605                 }
606 
607                 // append refinement bitset (aligned to word boundary)
608                 // _<refBits>
609                 wordPos = NumberOfWords(m_codePos);
610                 ASSERT(0 <= wordPos && wordPos < CodeBufferLen);
611                 refLen = NumberOfWords(bufferSize - sigLen);
612 
613                 for (UINT32 k=0; k < refLen; k++) {
614                         m_codeBuffer[wordPos++] = refBits[k];
615                 }
616                 m_codePos = wordPos << WordWidthLog;
617                 planeMask >>= 1;
618         }
619         ASSERT(0 <= m_codePos && m_codePos <= CodeBufferBitLen);
620 }

UINT32 CEncoder::CMacroBlock::DecomposeBitplane (UINT32 bufferSize, UINT32 planeMask, UINT32 codePos, UINT32 * sigBits, UINT32 * refBits, UINT32 * signBits, UINT32 & signLen, UINT32 & codeLen) [private]

Definition at line 632 of file Encoder.cpp.

632                                                                                                                                                                                        {
633         ASSERT(sigBits);
634         ASSERT(refBits);
635         ASSERT(signBits);
636         ASSERT(codePos < CodeBufferBitLen);
637 
638         UINT32 sigPos = 0;
639         UINT32 valuePos = 0, valueEnd;
640         UINT32 refPos = 0;
641 
642         // set output value
643         signLen = 0;
644 
645         // prepare RLE of Sigs and Signs
646         const UINT32 outStartPos = codePos;
647         UINT32 k = 3;
648         UINT32 runlen = 1 << k; // = 2^k
649         UINT32 count = 0;
650 
651         while (valuePos < bufferSize) {
652                 // search next 1 in m_sigFlagVector using searching with sentinel
653                 valueEnd = valuePos;
654                 while(!m_sigFlagVector[valueEnd]) { valueEnd++; }
655 
656                 // search 1's in m_value[plane][valuePos..valueEnd)
657                 // these 1's are significant bits
658                 while (valuePos < valueEnd) {
659                         if (GetBitAtPos(valuePos, planeMask)) {
660                                 // RLE encoding
661                                 // encode run of count 0's followed by a 1
662                                 // with codeword: 1<count>(signBits[signPos])
663                                 SetBit(m_codeBuffer, codePos++); 
664                                 if (k > 0) {
665                                         SetValueBlock(m_codeBuffer, codePos, count, k);
666                                         codePos += k;
667 
668                                         // adapt k (half the zero run-length)
669                                         k--; 
670                                         runlen >>= 1;
671                                 }
672 
673                                 // copy and write sign bit
674                                 if (m_value[valuePos] < 0) {
675                                         SetBit(signBits, signLen++);
676                                         SetBit(m_codeBuffer, codePos++);
677                                 } else {
678                                         ClearBit(signBits, signLen++);
679                                         ClearBit(m_codeBuffer, codePos++);
680                                 }
681 
682                                 // write a 1 to sigBits
683                                 SetBit(sigBits, sigPos++); 
684 
685                                 // update m_sigFlagVector
686                                 m_sigFlagVector[valuePos] = true;
687 
688                                 // prepare for next run
689                                 count = 0;
690                         } else {
691                                 // RLE encoding
692                                 count++;
693                                 if (count == runlen) {
694                                         // encode run of 2^k zeros by a single 0
695                                         ClearBit(m_codeBuffer, codePos++);
696                                         // adapt k (double the zero run-length)
697                                         if (k < WordWidth) {
698                                                 k++;
699                                                 runlen <<= 1;
700                                         }
701 
702                                         // prepare for next run
703                                         count = 0;
704                                 }
705 
706                                 // write 0 to sigBits
707                                 sigPos++;
708                         }
709                         valuePos++;
710                 }
711                 // refinement bit
712                 if (valuePos < bufferSize) {
713                         // write one refinement bit
714                         if (GetBitAtPos(valuePos++, planeMask)) {
715                                 SetBit(refBits, refPos);
716                         } else {
717                                 ClearBit(refBits, refPos);
718                         }
719                         refPos++;
720                 }
721         }
722         // RLE encoding of the rest of the plane
723         // encode run of count 0's followed by a 1
724         // with codeword: 1<count>(signBits[signPos])
725         SetBit(m_codeBuffer, codePos++); 
726         if (k > 0) {
727                 SetValueBlock(m_codeBuffer, codePos, count, k);
728                 codePos += k;
729         }
730         // write dmmy sign bit
731         SetBit(m_codeBuffer, codePos++);
732 
733         // write word filler zeros
734 
735         ASSERT(sigPos <= bufferSize);
736         ASSERT(refPos <= bufferSize);
737         ASSERT(signLen <= bufferSize);
738         ASSERT(valuePos == bufferSize);
739         ASSERT(codePos >= outStartPos && codePos < CodeBufferBitLen);
740         codeLen = codePos - outStartPos;
741 
742         return sigPos;
743 }

bool CEncoder::CMacroBlock::GetBitAtPos (UINT32 pos, UINT32 planeMask) const [inline], [private]

Definition at line 96 of file Encoder.h.

96 { return (abs(m_value[pos]) & planeMask) > 0; }

void CEncoder::CMacroBlock::Init (int lastLevelIndex) [inline]

Reinitialzes this macro block (allows reusage).

Parameters: lastLevelIndex Level length directory index of last encoded level: [0, nLevels)

Definition at line 71 of file Encoder.h.

71                                               {                         // initialize for reusage
72                         m_valuePos = 0;
73                         m_maxAbsValue = 0;
74                         m_codePos = 0;
75                         m_lastLevelIndex = lastLevelIndex;
76                 }

UINT8 CEncoder::CMacroBlock::NumberOfBitplanes () [private]

Definition at line 748 of file Encoder.cpp.

748                                              {
749         UINT8 cnt = 0;
750 
751         // determine number of bitplanes for max value
752         if (m_maxAbsValue > 0) {
753                 while (m_maxAbsValue > 0) {
754                         m_maxAbsValue >>= 1; cnt++;
755                 }
756                 if (cnt == MaxBitPlanes + 1) cnt = 0;
757                 // end cs
758                 ASSERT(cnt <= MaxBitPlanes);
759                 ASSERT((cnt >> MaxBitPlanesLog) == 0);
760                 return cnt;
761         } else {
762                 return 1;
763         }
764 }

UINT32 CEncoder::CMacroBlock::RLESigns (UINT32 codePos, UINT32 * signBits, UINT32 signLen) [private]

Definition at line 772 of file Encoder.cpp.

772                                                                                      {
773         ASSERT(signBits);
774         ASSERT(0 <= codePos && codePos < CodeBufferBitLen);
775         ASSERT(0 < signLen && signLen <= BufferSize);
776         
777         const UINT32  outStartPos = codePos;
778         UINT32 k = 0;
779         UINT32 runlen = 1 << k; // = 2^k
780         UINT32 count = 0;
781         UINT32 signPos = 0;
782 
783         while (signPos < signLen) {
784                 // search next 0 in signBits starting at position signPos
785                 count = SeekBit1Range(signBits, signPos, __min(runlen, signLen - signPos));
786                 // count 1's found
787                 if (count == runlen) {
788                         // encode run of 2^k ones by a single 1
789                         signPos += count; 
790                         SetBit(m_codeBuffer, codePos++);
791                         // adapt k (double the 1's run-length)
792                         if (k < WordWidth) {
793                                 k++; 
794                                 runlen <<= 1;
795                         }
796                 } else {
797                         // encode run of count 1's followed by a 0
798                         // with codeword: 0(count)
799                         signPos += count + 1;
800                         ClearBit(m_codeBuffer, codePos++);
801                         if (k > 0) {
802                                 SetValueBlock(m_codeBuffer, codePos, count, k);
803                                 codePos += k;
804                         }
805                         // adapt k (half the 1's run-length)
806                         if (k > 0) {
807                                 k--; 
808                                 runlen >>= 1;
809                         }
810                 }
811         }
812         ASSERT(signPos == signLen || signPos == signLen + 1);
813         ASSERT(codePos >= outStartPos && codePos < CodeBufferBitLen);
814         return codePos - outStartPos;
815 }