V210 issue fix + correct packing

internal/flowdef/flowdef.go

@@ -132,8 +132,8 @@ func (v Video) Validate() error {
 	if v.ColorSpace != ColorSpaceBT709 {
 		return fmt.Errorf("colorspace must be %q, got %q", ColorSpaceBT709, v.ColorSpace)
 	}
-	if v.FrameWidth == 0 || v.FrameWidth%6 != 0 {
-		return fmt.Errorf("frame_width must be greater than zero and divisible by 6, got %d", v.FrameWidth)
+	if v.FrameWidth == 0 || v.FrameWidth%2 != 0 {
+		return fmt.Errorf("frame_width must be greater than zero and even for 4:2:2 video, got %d", v.FrameWidth)
 	}
 	if v.FrameHeight == 0 {
 		return fmt.Errorf("frame_height must be greater than zero")

internal/flowdef/flowdef_test.go

@@ -28,10 +28,10 @@ func TestNewV210Video(t *testing.T) {
 	}
 }
 
-func TestNewV210VideoRejectsInvalidWidth(t *testing.T) {
+func TestNewV210VideoRejectsOddWidth(t *testing.T) {
 	_, err := NewV210Video(testVideoID, 1919, 1080, Rational{Numerator: 25, Denominator: 1})
-	if err == nil || !strings.Contains(err.Error(), "divisible by 6") {
-		t.Fatalf("error = %v, want width divisibility error", err)
+	if err == nil || !strings.Contains(err.Error(), "even") {
+		t.Fatalf("error = %v, want even-width error", err)
 	}
 }