From 43a4771cd06600fa95dbea7ddc8774537d537771 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Sat, 14 Mar 2026 20:29:36 +0100
Subject: [PATCH] opus/dec_celt: avoid emph_coeff becoming a subnormal

This happens for silence frames, which on many CPUs massively slows down
processing the decoded output.

Cf. https://github.com/Genymobile/scrcpy/issues/6715

(cherry picked from commit 5b112b17c009b57a0063ca965dd49dc7e018d771)
---
 libavcodec/opus/dec_celt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/opus/dec_celt.c b/libavcodec/opus/dec_celt.c
index 3feb4a4e47..a43d63d9db 100644
--- a/libavcodec/opus/dec_celt.c
+++ b/libavcodec/opus/dec_celt.c
@@ -463,6 +463,8 @@ int ff_celt_decode_frame(CeltFrame *f, OpusRangeCoder *rc,
                                                   block->emph_coeff,
                                                   ff_opus_deemph_weights,
                                                   frame_size);
+        if (!isnormal(block->emph_coeff))
+            block->emph_coeff = 0.0;
     }
 
     if (channels == 1)