major remote desktop improvements

2026-07-30 00:22:08 -05:00
parent a68172538d
commit 095a119bf4
35 changed files with 984 additions and 120 deletions
@@ -0,0 +1,45 @@
+package h264util
+
+type AccessUnit struct {
+	HasSPS bool
+	HasPPS bool
+	HasIDR bool
+}
+
+func InspectAnnexB(data []byte) AccessUnit {
+	var out AccessUnit
+	for i := 0; i+3 < len(data); {
+		startCodeLen := 0
+		switch {
+		case i+3 < len(data) && data[i] == 0 && data[i+1] == 0 && data[i+2] == 1:
+			startCodeLen = 3
+		case i+4 < len(data) && data[i] == 0 && data[i+1] == 0 && data[i+2] == 0 && data[i+3] == 1:
+			startCodeLen = 4
+		}
+		if startCodeLen == 0 {
+			i++
+			continue
+		}
+		nal := i + startCodeLen
+		if nal >= len(data) {
+			break
+		}
+		switch data[nal] & 0x1f {
+		case 5:
+			out.HasIDR = true
+		case 7:
+			out.HasSPS = true
+		case 8:
+			out.HasPPS = true
+		}
+		if out.HasSPS && out.HasPPS && out.HasIDR {
+			return out
+		}
+		i = nal + 1
+	}
+	return out
+}
+
+func IsIDR(data []byte) bool {
+	return InspectAnnexB(data).HasIDR
+}
@@ -0,0 +1,22 @@
+package h264util
+
+import "testing"
+
+func TestInspectAnnexB(t *testing.T) {
+	data := []byte{
+		0, 0, 0, 1, 0x67, 1, 2, 3,
+		0, 0, 1, 0x68, 4, 5,
+		0, 0, 0, 1, 0x65, 6, 7,
+	}
+	got := InspectAnnexB(data)
+	if !got.HasSPS || !got.HasPPS || !got.HasIDR {
+		t.Fatalf("InspectAnnexB() = %+v", got)
+	}
+}
+
+func TestInspectAnnexBRejectsDeltaFrame(t *testing.T) {
+	got := InspectAnnexB([]byte{0, 0, 1, 0x41, 1, 2, 3})
+	if got.HasSPS || got.HasPPS || got.HasIDR {
+		t.Fatalf("delta frame was misclassified: %+v", got)
+	}
+}