mp4 fix samplesize atom bug

format/mp4/atom/samplesize.go

@@ -0,0 +1,97 @@
+
+package atom
+
+import (
+	"io"
+)
+
+type SampleSize struct {
+	Version    int
+	Flags      int
+	SampleSize int
+	Entries    []int
+}
+
+func ReadSampleSize(r *io.LimitedReader) (res *SampleSize, err error) {
+
+	self := &SampleSize{}
+	if self.Version, err = ReadInt(r, 1); err != nil {
+		return
+	}
+	if self.Flags, err = ReadInt(r, 3); err != nil {
+		return
+	}
+	if self.SampleSize, err = ReadInt(r, 4); err != nil {
+		return
+	}
+	if self.SampleSize != 0 {
+		return
+	}
+	var count int
+	if count, err = ReadInt(r, 4); err != nil {
+		return
+	}
+	self.Entries = make([]int, count)
+	for i := 0; i < count; i++ {
+		if self.Entries[i], err = ReadInt(r, 4); err != nil {
+			return
+		}
+	}
+	res = self
+	return
+}
+func WriteSampleSize(w io.WriteSeeker, self *SampleSize) (err error) {
+
+	var aw *Writer
+	if aw, err = WriteAtomHeader(w, "stsz"); err != nil {
+		return
+	}
+	w = aw
+	if err = WriteInt(w, self.Version, 1); err != nil {
+		return
+	}
+	if err = WriteInt(w, self.Flags, 3); err != nil {
+		return
+	}
+	if err = WriteInt(w, self.SampleSize, 4); err != nil {
+		return
+	}
+	if self.SampleSize != 0 {
+		return
+	}
+	if err = WriteInt(w, len(self.Entries), 4); err != nil {
+		return
+	}
+	for _, elem := range self.Entries {
+		if err = WriteInt(w, elem, 4); err != nil {
+			return
+		}
+	}
+	if err = aw.Close(); err != nil {
+		return
+	}
+	return
+}
+func WalkSampleSize(w Walker, self *SampleSize) {
+
+	w.StartStruct("SampleSize")
+	w.Name("Version")
+	w.Int(self.Version)
+	w.Name("Flags")
+	w.Int(self.Flags)
+	w.Name("SampleSize")
+	w.Int(self.SampleSize)
+	for i, item := range self.Entries {
+		if w.FilterArrayItem("SampleSize", "Entries", i, len(self.Entries)) {
+			w.Name("Entries")
+			w.Int(item)
+		} else {
+			w.ArrayLeft(i, len(self.Entries))
+			break
+		}
+	}
+	w.EndStruct()
+	return
+}
+
+