From 8b4fa817117e28f3962568dc865454849a02abb7 Mon Sep 17 00:00:00 2001
From: arancormonk <180709949+arancormonk@users.noreply.github.com>
Date: Wed, 3 Sep 2025 21:38:50 -0500
Subject: [PATCH] =?UTF-8?q?rtl=5Fsdr=5Ffm:=20consume=20HB=20cascade=20outp?=
 =?UTF-8?q?ut=20in-place=20to=20avoid=20the=20final=20memcpy.=20Track=20th?=
 =?UTF-8?q?e=20current=20buffer=20and=20assign=20lowpassed=20to=20the=20la?=
 =?UTF-8?q?st=20stage=E2=80=99s=20output,=20preserving=20correctness=20whi?=
 =?UTF-8?q?le=20reducing=20memory=20traffic.?=
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---
 src/rtl_sdr_fm.cpp | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/rtl_sdr_fm.cpp b/src/rtl_sdr_fm.cpp
index 88764f8..186ac74 100644
--- a/src/rtl_sdr_fm.cpp
+++ b/src/rtl_sdr_fm.cpp
@@ -1608,10 +1608,8 @@ void full_demod(struct demod_state *d)
 				in_len = out_len_interleaved;
 				dst = (src == d->hb_workbuf) ? d->lowpassed : d->hb_workbuf;
 			}
-			/* Final output resides in 'src' with length in_len */
-			if (d->lowpassed != src) {
-				memcpy(d->lowpassed, src, (size_t)in_len * sizeof(int16_t));
-			}
+			/* Final output resides in 'src' with length in_len; consume in-place (no copy) */
+			d->lowpassed = src;
 			d->lp_len = in_len;
 			/* No droop compensation for half-band cascade */
 		} else {