codec/h264/h264dec/cabac.go: added binarization process for coded block pattern

codec/h264/h264dec/cabacenc.go

@@ -28,6 +28,7 @@ package h264dec
 
 import (
 	"errors"
+	"fmt"
 	"math"
 )
 
@@ -220,3 +221,23 @@ func subMbTypeBinString(v, slice int) ([]int, error) {
 		return nil, errBadSubMbSliceType
 	}
 }
+
+// codedBlockPatternBinString returns the binarization for the syntax element
+// coded_block_pattern as defined by section 9.3.2.6 in specifications.
+func codedBlockPatternBinString(luma, chroma, arrayType int) ([]int, error) {
+	p, err := fixedLenBinString(luma, 15)
+	if err != nil {
+		return nil, fmt.Errorf("fixed length binarization failed with error: %v", err)
+	}
+
+	if arrayType == 0 || arrayType == 3 {
+		return p, nil
+	}
+
+	s, err := truncUnaryBinString(chroma, 2)
+	if err != nil {
+		return nil, fmt.Errorf("truncated unary binarization failed with error: %v", err)
+	}
+
+	return append(p, s...), nil
+}