[x265] [PATCH 1 of 2] Computing RPS from a fixed GOP
Deepthi Devaki Akkoorath
deepthidevaki at multicorewareinc.com
Fri Aug 23 08:18:06 CEST 2013
On Fri, Aug 23, 2013 at 1:02 AM, Steve Borho <steve at borho.org> wrote:
>
>
>
> On Thu, Aug 22, 2013 at 7:54 AM, <shazeb at multicorewareinc.com> wrote:
>
>> # HG changeset patch
>> # User Shazeb N Khan
>> # Date 1377173041 -19800
>> # Thu Aug 22 17:34:01 2013 +0530
>> # Node ID 34c63b8389c6f688cec7ac869943df32577fb28e
>> # Parent 9f38435eee26dfc31d7fbd81ca5357f4a5b4d5b8
>> Computing RPS from a fixed GOP
>>
>
> great start, I have a few comments
>
>
>>
>> diff -r 9f38435eee26 -r 34c63b8389c6 source/Lib/TLibCommon/TComSlice.h
>> --- a/source/Lib/TLibCommon/TComSlice.h Thu Aug 22 15:17:49 2013 +0800
>> +++ b/source/Lib/TLibCommon/TComSlice.h Thu Aug 22 17:34:01 2013 +0530
>> @@ -66,18 +66,13 @@
>> {
>> private:
>>
>> - Int m_numberOfPictures;
>> - Int m_numberOfNegativePictures;
>> - Int m_numberOfPositivePictures;
>> - Int m_numberOfLongtermPictures;
>> - Int m_deltaPOC[MAX_NUM_REF_PICS];
>> - Int m_POC[MAX_NUM_REF_PICS];
>> - Bool m_used[MAX_NUM_REF_PICS];
>> - Bool m_interRPSPrediction;
>> + // Parameters for inter RPS prediction
>> Int m_deltaRIdxMinus1;
>> Int m_deltaRPS;
>> Int m_numRefIdc;
>> Int m_refIdc[MAX_NUM_REF_PICS + 1];
>> +
>> + // Parameters for long term references
>> Bool m_bCheckLTMSB[MAX_NUM_REF_PICS];
>> Int m_pocLSBLT[MAX_NUM_REF_PICS];
>> Int m_deltaPOCMSBCycleLT[MAX_NUM_REF_PICS];
>> @@ -85,6 +80,17 @@
>>
>> public:
>>
>> + Int m_numberOfPictures;
>> + Int m_numberOfNegativePictures;
>> + Int m_numberOfPositivePictures;
>> + Int m_deltaPOC[MAX_NUM_REF_PICS];
>> + Bool m_used[MAX_NUM_REF_PICS];
>> + Int m_POC[MAX_NUM_REF_PICS];
>> +
>> + Bool m_interRPSPrediction;
>> + Int m_numberOfLongtermPictures; // Zero when disabled
>> +
>> +
>> TComReferencePictureSet();
>> virtual ~TComReferencePictureSet();
>> Int getPocLSBLT(Int i) { return
>> m_pocLSBLT[i]; }
>> diff -r 9f38435eee26 -r 34c63b8389c6 source/encoder/dpb.cpp
>> --- a/source/encoder/dpb.cpp Thu Aug 22 15:17:49 2013 +0800
>> +++ b/source/encoder/dpb.cpp Thu Aug 22 17:34:01 2013 +0530
>> @@ -31,6 +31,8 @@
>>
>> using namespace x265;
>>
>> +#define MAX_REFD_BY_CUR 8
>>
>
> Does the HM already have a similar define (I think it is 16 or 32)
>
HM defines MAX_NUM_REF = 16, which is the maximum number of reference
pictures you can have in List0 and List1. You may not want to use
MAX_NUM_REF pictures as references always and hence do not want to put them
in RPS. Since we do not have much information about which previously coded
pictures must be used as reference for the current picture, we are
considering previous MAX_REFD_BY_CUR number of pictures to be included in
RPS.
>
>
>> +
>> DPB::~DPB()
>> {
>> while (!m_picList.empty())
>> @@ -44,7 +46,6 @@
>> void DPB::recycleUnreferenced(TComList<TComPic*> freeList)
>> {
>> // move unreferenced pictures from picList to freeList for recycle
>> - TComSlice::sortPicList(m_picList);
>>
>
> You should remove the comment above if you remove the sort call
>
>
>> TComList<TComPic*>::iterator iterPic = m_picList.begin();
>> while (iterPic != m_picList.end())
>> {
>> @@ -71,7 +72,7 @@
>> int pocCurr = pic->getSlice()->getPOC();
>>
>> Bool forceIntra = m_cfg->param.keyframeMax == 1 || (pocCurr %
>> m_cfg->param.keyframeMax == 0) || pocCurr == 0;
>> - m_picList.pushBack(pic);
>> + m_picList.pushFront(pic);
>> frameEncoder->initSlice(pic, forceIntra, gopIdx);
>>
>> TComSlice* slice = pic->getSlice();
>> @@ -90,10 +91,14 @@
>> {
>> slice->setTemporalLayerNonReferenceFlag(false);
>> }
>> + else if(slice->getSliceType() == B_SLICE)
>> + {
>> + slice->setReferenced(false); //
>> Disallowing B frame from being referenced, unless the 'lookahead' intends to
>> + slice->setTemporalLayerNonReferenceFlag(true);
>> + }
>> else
>> {
>> - // m_refPic is true if this frame is used as a motion reference
>> -
>> slice->setTemporalLayerNonReferenceFlag(!m_cfg->getGOPEntry(gopIdx).m_refPic);
>> + slice->setTemporalLayerNonReferenceFlag(false);
>> }
>>
>
> This whole set of logic could be reduced to:
>
> slice->setReferenced(slice->getSliceType() != B_SLICE);
> slice->setTemporalLayerNonReferenceFlag(!slice->getReferenced());
>
>
>> // Set the nal unit type
>> @@ -118,21 +123,19 @@
>>
>> // Do decoding refresh marking if any
>> slice->decodingRefreshMarking(m_pocCRA, m_bRefreshPending,
>> m_picList);
>> - selectReferencePictureSet(slice, frameEncoder, pocCurr, gopIdx);
>> - slice->getRPS()->setNumberOfLongtermPictures(0);
>> +
>> + computeRPS(pocCurr, slice->isIRAP(), slice->getLocalRPS());
>> + slice->setRPS(slice->getLocalRPS());
>> + slice->setRPSidx(-1); // To force using RPS from
>> slice, rather than from SPS
>>
>> - if ((slice->checkThatAllRefPicsAreAvailable(m_picList,
>> slice->getRPS(), false) != 0) || (slice->isIRAP()))
>> - {
>> - slice->createExplicitReferencePictureSetFromReference(m_picList,
>> slice->getRPS(), slice->isIRAP());
>> - }
>> slice->applyReferencePictureSet(m_picList, slice->getRPS());
>>
>> arrangeLongtermPicturesInRPS(slice, frameEncoder);
>> TComRefPicListModification* refPicListModification =
>> slice->getRefPicListModification();
>> refPicListModification->setRefPicListModificationFlagL0(false);
>> refPicListModification->setRefPicListModificationFlagL1(false);
>>
>
> I wonder if the above three lines could be moved to the TComSlice
> constructor?
>
Yes. We could move it. Reference pictures in RPS is sorted by deltaPOCs.
List0 and List1 will have pics in same order as in RPS. If for some reason
we want to reorder the pictures in List0 and List1, we must set
refPicListModification.
But right now we are not using it.
>
>
>> - slice->setNumRefIdx(REF_PIC_LIST_0,
>> min(m_cfg->getGOPEntry(gopIdx).m_numRefPicsActive,
>> slice->getRPS()->getNumberOfPictures()));
>> - slice->setNumRefIdx(REF_PIC_LIST_1,
>> min(m_cfg->getGOPEntry(gopIdx).m_numRefPicsActive,
>> slice->getRPS()->getNumberOfPictures()));
>> + slice->setNumRefIdx(REF_PIC_LIST_0,
>> slice->getRPS()->getNumberOfPictures() / 2 + 1); // TO DO: how to decide
>> the number of references to be included in each list
>> + slice->setNumRefIdx(REF_PIC_LIST_1,
>> slice->getRPS()->getNumberOfPictures() / 2 + 1);
>>
>
> To answer your question, we need to know how the number of reference idx
> are used in the encoder/decoder, and whether they are dependent on the
> slice type at all.
>
numRefIdx specify the number of pictures in List0 and List1 individually. A
tempList0 and tempList1 is derived from RPS and then only first numRefIdx
from tempList0 and tempList1 is put into List0 and List1. MotionEstimation
has to be done for numRefIdx reference pictures. Can we also expect this
information (numRefIdx and n(RPS)) directly/indirectly from the lookahead
when it is complete?
>
>
>>
>> slice->setRefPicList(m_picList);
>>
>> @@ -148,11 +151,13 @@
>> // what is setColFromL0Flag() for?
>>
>> // select colDir
>> + TComReferencePictureSet *rps = slice->getRPS();
>> +
>> UInt colDir = 1;
>> int closeLeft = 1, closeRight = -1;
>> - for (int i = 0; i < m_cfg->getGOPEntry(gopIdx).m_numRefPics; i++)
>> + for (int i = 0; i < rps->m_numberOfPictures; i++)
>> {
>> - int ref = m_cfg->getGOPEntry(gopIdx).m_referencePics[i];
>> + int ref = rps->m_deltaPOC[i];
>> if (ref > 0 && (ref < closeRight || closeRight == -1))
>> {
>> closeRight = ref;
>> @@ -246,6 +251,36 @@
>> slice->setNextSlice(false);
>> }
>>
>> +void DPB::computeRPS(int curPoc, bool isRAP, TComReferencePictureSet *
>> rps)
>> +{
>> + curPoc;
>> + TComPic * refPic;
>> + int poci=0, numNeg=0, numPos=0;
>> +
>> + TComList<TComPic*>::iterator iterPic = m_picList.begin();
>> + while ((iterPic != m_picList.end())&&(poci<MAX_REFD_BY_CUR))
>> + {
>> + refPic = *(iterPic);
>> + if ((refPic->getPOC() !=
>> curPoc)&&(refPic->getSlice()->isReferenced()))
>> + {
>> + rps->m_POC[poci] = refPic->getPOC();
>> + rps->m_deltaPOC[poci] = rps->m_POC[poci] - curPoc;
>> + (rps->m_deltaPOC[poci] < 0) ? numNeg++: numPos++;
>> + rps->m_used[poci] = true && (!isRAP);
>>
>
> the "true &&" here is redundant
>
>
>> + poci++;
>> + }
>> + iterPic++;
>> + }
>> +
>> + rps->m_numberOfPictures = poci;
>> + rps->m_numberOfPositivePictures = numPos;
>> + rps->m_numberOfNegativePictures = numNeg;
>> + rps->m_numberOfLongtermPictures = 0;
>> + rps->m_interRPSPrediction = false; // To be changed later
>> when needed
>> +
>> + rps->sortDeltaPOC(); // TO DO: check whether
>> entire process of sorting is needed here
>> +}
>> +
>> // This is a function that determines what Reference Picture Set to use
>> for a
>> // specific slice (with POC = POCCurr)
>> void DPB::selectReferencePictureSet(TComSlice* slice, FrameEncoder
>> *frameEncoder, int curPOC, int gopID)
>> @@ -514,7 +549,7 @@
>> m_gopList[i].m_QPFactor = factors[offsets[i]];
>> m_gopList[i].m_QPOffset = offsets[i];
>> m_gopList[i].m_deltaRPS = rps[i];
>> - m_gopList[i].m_sliceType = 'B';
>> + m_gopList[i].m_sliceType = (i!=4)? 'P': 'B';
>>
>
> is this backwards? don't you want P for the 4th (and possibly 1st)
> frame(s) and B for the rest?
>
>
>> m_gopList[i].m_numRefPicsActive = i ? 2 : 4;
>> m_gopList[i].m_numRefPics = i == 1 ? 3 : 4;
>> m_gopList[i].m_interRPSPrediction = i ? 1 : 0;
>>
>
> Can these three fields be removed yet?
>
>
>> diff -r 9f38435eee26 -r 34c63b8389c6 source/encoder/dpb.h
>> --- a/source/encoder/dpb.h Thu Aug 22 15:17:49 2013 +0800
>> +++ b/source/encoder/dpb.h Thu Aug 22 17:34:01 2013 +0530
>> @@ -62,6 +62,8 @@
>>
>> void selectReferencePictureSet(TComSlice* slice,
>> x265::FrameEncoder*, int curPoc, int gopID);
>>
>> + void computeRPS(int curPoc, bool isRAP, TComReferencePictureSet *
>> rps);
>> +
>> int getReferencePictureSetIdxForSOP(int pocCur, int GOPid);
>>
>> void arrangeLongtermPicturesInRPS(TComSlice *, x265::FrameEncoder
>> *frameEncoder);
>>
>> _______________________________________________
>> x265-devel mailing list
>> x265-devel at videolan.org
>> https://mailman.videolan.org/listinfo/x265-devel
>>
>>
>
>
> --
> Steve Borho
>
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
>
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