diff --git a/internal/core/formatprocessor_h264.go b/internal/core/formatprocessor_h264.go
index 20b95c00..932626a0 100644
--- a/internal/core/formatprocessor_h264.go
+++ b/internal/core/formatprocessor_h264.go
@@ -222,7 +222,9 @@ func (t *formatProcessorH264) process(dat data, hasNonRTSPReaders bool) error {
 				t.decoder = t.format.CreateDecoder()
 			}
 
-			tdata.rtpPackets = nil
+			if t.encoder != nil {
+				tdata.rtpPackets = nil
+			}
 
 			// DecodeUntilMarker() is necessary, otherwise Encode() generates partial groups
 			nalus, pts, err := t.decoder.DecodeUntilMarker(pkt)
diff --git a/internal/core/formatprocessor_h265.go b/internal/core/formatprocessor_h265.go
index 7091b3f5..3027e624 100644
--- a/internal/core/formatprocessor_h265.go
+++ b/internal/core/formatprocessor_h265.go
@@ -170,7 +170,9 @@ func (t *formatProcessorH265) process(dat data, hasNonRTSPReaders bool) error {
 				t.decoder = t.format.CreateDecoder()
 			}
 
-			tdata.rtpPackets = nil
+			if t.encoder != nil {
+				tdata.rtpPackets = nil
+			}
 
 			// DecodeUntilMarker() is necessary, otherwise Encode() generates partial groups
 			nalus, pts, err := t.decoder.DecodeUntilMarker(pkt)