diff --git a/internal/pipewire/core.go b/internal/pipewire/core.go
index 1ef2f79..57e1f5b 100644
--- a/internal/pipewire/core.go
+++ b/internal/pipewire/core.go
@@ -172,10 +172,8 @@ type CoreHello struct {
 // Size satisfies [KnownSize] with a constant value.
 func (c *CoreHello) Size() Word { return SizePrefix + Size(SizeInt) }
 
-// MarshalBinary satisfies [encoding.BinaryMarshaler] via [MarshalAppend].
-func (c *CoreHello) MarshalBinary() ([]byte, error) {
-	return MarshalAppend(make([]byte, 0, 24), c)
-}
+// MarshalBinary satisfies [encoding.BinaryMarshaler] via [Marshal].
+func (c *CoreHello) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
 func (c *CoreHello) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
@@ -198,10 +196,8 @@ type CoreSync struct {
 // Size satisfies [KnownSize] with a constant value.
 func (c *CoreSync) Size() Word { return SizePrefix + Size(SizeInt) + Size(SizeInt) }
 
-// MarshalBinary satisfies [encoding.BinaryMarshaler] via [MarshalAppend].
-func (c *CoreSync) MarshalBinary() ([]byte, error) {
-	return MarshalAppend(make([]byte, 0, 40), c)
-}
+// MarshalBinary satisfies [encoding.BinaryMarshaler] via [Marshal].
+func (c *CoreSync) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
 func (c *CoreSync) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
@@ -224,10 +220,8 @@ type CoreGetRegistry struct {
 // Size satisfies [KnownSize] with a constant value.
 func (c *CoreGetRegistry) Size() Word { return SizePrefix + Size(SizeInt) + Size(SizeInt) }
 
-// MarshalBinary satisfies [encoding.BinaryMarshaler] via [MarshalAppend].
-func (c *CoreGetRegistry) MarshalBinary() ([]byte, error) {
-	return MarshalAppend(make([]byte, 0, 40), c)
-}
+// MarshalBinary satisfies [encoding.BinaryMarshaler] via [Marshal].
+func (c *CoreGetRegistry) MarshalBinary() ([]byte, error) { return Marshal(c) }
 
 // UnmarshalBinary satisfies [encoding.BinaryUnmarshaler] via [Unmarshal].
 func (c *CoreGetRegistry) UnmarshalBinary(data []byte) error { return Unmarshal(data, c) }
diff --git a/internal/pipewire/pod.go b/internal/pipewire/pod.go
index 80c798e..3a94db5 100644
--- a/internal/pipewire/pod.go
+++ b/internal/pipewire/pod.go
@@ -125,7 +125,13 @@ type UnsupportedSizeError int
 func (e UnsupportedSizeError) Error() string { return "size out of range: " + strconv.Itoa(int(e)) }
 
 // Marshal returns the PipeWire POD encoding of v.
-func Marshal(v any) ([]byte, error) { return MarshalAppend(make([]byte, 0), v) }
+func Marshal(v any) ([]byte, error) {
+	var data []byte
+	if s, ok := v.(KnownSize); ok {
+		data = make([]byte, 0, s.Size())
+	}
+	return MarshalAppend(data, v)
+}
 
 // MarshalAppend appends the PipeWire POD encoding of v to data.
 func MarshalAppend(data []byte, v any) ([]byte, error) {