diff --git a/src/liblzma/common/filter_decoder.c b/src/liblzma/common/filter_decoder.c
index 241b272d..c969a554 100644
--- a/src/liblzma/common/filter_decoder.c
+++ b/src/liblzma/common/filter_decoder.c
@@ -133,7 +133,7 @@ static const lzma_filter_decoder decoders[] = {
 	{
 		.id = LZMA_FILTER_DELTA,
 		.init = &lzma_delta_decoder_init,
-		.memusage = NULL,
+		.memusage = &lzma_delta_coder_memusage,
 		.props_decode = &lzma_delta_props_decode,
 	},
 #endif
diff --git a/src/liblzma/common/filter_encoder.c b/src/liblzma/common/filter_encoder.c
index a839fe70..c9d6b91e 100644
--- a/src/liblzma/common/filter_encoder.c
+++ b/src/liblzma/common/filter_encoder.c
@@ -159,7 +159,7 @@ static const lzma_filter_encoder encoders[] = {
 	{
 		.id = LZMA_FILTER_DELTA,
 		.init = &lzma_delta_encoder_init,
-		.memusage = NULL,
+		.memusage = &lzma_delta_coder_memusage,
 		.chunk_size = NULL,
 		.props_size_get = NULL,
 		.props_size_fixed = 1,