codec/h264/h264dec: wrote DecRefPicMarking type with constructor and gave to SliceHeader type

codec/h264/h264dec/slice.go

@@ -254,6 +254,78 @@ func NewPredWeightTable(br *bits.BitReader, h *SliceHeader) (*PredWeightTable, e
 	return p, nil
 }
 
+// DecRefPicMarking provides elements of a dec_ref_pic_marking syntax structure
+// as defined in section 7.3.3.3 of the specifications.
+type DecRefPicMarking struct {
+	NoOutputOfPriorPicsFlag          bool
+	LongTermReferenceFlag            bool
+	AdaptiveRefPicMarkingModeFlag    bool
+	MemoryManagementControlOperation int
+	DifferenceOfPicNumsMinus1        int
+	LongTermFrameIdx                 int
+	MaxLongTermFrameIdxPlus1         int
+}
+
+// NewDecRefPicMarking parses elements of a dec_ref_pic_marking following the
+// syntax structure defined in section 7.3.3.3, and returns as a new
+// DecRefPicMarking.
+func NewDecRefPicMarking(br *bits.BitReader, idrPic bool, h *SliceHeader) (*DecRefPicMarking, error) {
+	d := &DecRefPicMarking{}
+	if idrPic {
+		b, err := br.ReadBits(1)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not read NoOutputOfPriorPicsFlag")
+		}
+		d.NoOutputOfPriorPicsFlag = b == 1
+
+		b, err = br.ReadBits(1)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not read LongTermReferenceFlag")
+		}
+		d.LongTermReferenceFlag = b == 1
+	} else {
+		b, err := br.ReadBits(1)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not read AdaptiveRefPicMarkingModeFlag")
+		}
+		d.AdaptiveRefPicMarkingModeFlag = b == 1
+
+		if d.AdaptiveRefPicMarkingModeFlag {
+			d.MemoryManagementControlOperation, err = readUe(br)
+			if err != nil {
+				return nil, errors.Wrap(err, "could not parse MemoryManagementControlOperation")
+			}
+			for d.MemoryManagementControlOperation != 0 {
+				if d.MemoryManagementControlOperation == 1 || d.MemoryManagementControlOperation == 3 {
+					d.DifferenceOfPicNumsMinus1, err = readUe(br)
+					if err != nil {
+						return nil, errors.Wrap(err, "could not parse MemoryManagementControlOperation")
+					}
+				}
+				if d.MemoryManagementControlOperation == 2 {
+					h.RefPicListModification.LongTermPicNum, err = readUe(br)
+					if err != nil {
+						return nil, errors.Wrap(err, "could not parse LongTermPicNum")
+					}
+				}
+				if d.MemoryManagementControlOperation == 3 || d.MemoryManagementControlOperation == 6 {
+					d.LongTermFrameIdx, err = readUe(br)
+					if err != nil {
+						return nil, errors.Wrap(err, "could not parse LongTermFrameIdx")
+					}
+				}
+				if d.MemoryManagementControlOperation == 4 {
+					d.MaxLongTermFrameIdxPlus1, err = readUe(br)
+					if err != nil {
+						return nil, errors.Wrap(err, "could not parse MaxLongTermFrameIdxPlus1")
+					}
+				}
+			}
+		}
+	}
+	return d, nil
+}
+
 type SliceHeader struct {
 	FirstMbInSlice          int
 	SliceType               int
@@ -271,19 +343,9 @@ type SliceHeader struct {
 	NumRefIdxActiveOverride bool
 	NumRefIdxL0ActiveMinus1 int
 	NumRefIdxL1ActiveMinus1 int
-
 	*RefPicListModification
 	*PredWeightTable
-
-	// dec_ref_pic_marking
-	NoOutputOfPriorPicsFlag          bool
-	LongTermReferenceFlag            bool
-	AdaptiveRefPicMarkingModeFlag    bool
-	MemoryManagementControlOperation int
-	DifferenceOfPicNumsMinus1        int
-	LongTermFrameIdx                 int
-	MaxLongTermFrameIdxPlus1         int
-
+	*DecRefPicMarking
 	CabacInit               int
 	SliceQpDelta            int
 	SpForSwitch             bool
@@ -1297,58 +1359,10 @@ func NewSliceContext(videoStream *VideoStream, nalUnit *NalUnit, rbsp []byte, sh
 	}
 	if nalUnit.RefIdc != 0 {
 		// devRefPicMarking()
-		if idrPic {
-			b, err := br.ReadBits(1)
+		header.DecRefPicMarking, err = NewDecRefPicMarking(br, idrPic, &header)
 		if err != nil {
-				return nil, errors.Wrap(err, "could not read NoOutputOfPriorPicsFlag")
+			return nil, errors.Wrap(err, "could not parse DecRefPicMarking")
 		}
-			header.NoOutputOfPriorPicsFlag = b == 1
-
-			b, err = br.ReadBits(1)
-			if err != nil {
-				return nil, errors.Wrap(err, "could not read LongTermReferenceFlag")
-			}
-			header.LongTermReferenceFlag = b == 1
-		} else {
-			b, err := br.ReadBits(1)
-			if err != nil {
-				return nil, errors.Wrap(err, "could not read AdaptiveRefPicMarkingModeFlag")
-			}
-			header.AdaptiveRefPicMarkingModeFlag = b == 1
-
-			if header.AdaptiveRefPicMarkingModeFlag {
-				header.MemoryManagementControlOperation, err = readUe(br)
-				if err != nil {
-					return nil, errors.Wrap(err, "could not parse MemoryManagementControlOperation")
-				}
-				for header.MemoryManagementControlOperation != 0 {
-					if header.MemoryManagementControlOperation == 1 || header.MemoryManagementControlOperation == 3 {
-						header.DifferenceOfPicNumsMinus1, err = readUe(br)
-						if err != nil {
-							return nil, errors.Wrap(err, "could not parse MemoryManagementControlOperation")
-						}
-					}
-					if header.MemoryManagementControlOperation == 2 {
-						header.RefPicListModification.LongTermPicNum, err = readUe(br)
-						if err != nil {
-							return nil, errors.Wrap(err, "could not parse LongTermPicNum")
-						}
-					}
-					if header.MemoryManagementControlOperation == 3 || header.MemoryManagementControlOperation == 6 {
-						header.LongTermFrameIdx, err = readUe(br)
-						if err != nil {
-							return nil, errors.Wrap(err, "could not parse LongTermFrameIdx")
-						}
-					}
-					if header.MemoryManagementControlOperation == 4 {
-						header.MaxLongTermFrameIdxPlus1, err = readUe(br)
-						if err != nil {
-							return nil, errors.Wrap(err, "could not parse MaxLongTermFrameIdxPlus1")
-						}
-					}
-				}
-			}
-		} // end decRefPicMarking
 	}
 	if pps.EntropyCodingMode == 1 && sliceType != "I" && sliceType != "SI" {
 		header.CabacInit, err = readUe(br)