diff --git a/ChangeLog b/ChangeLog
index 87a1b28f..42e9b4af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,9 @@
 - add _source load support for pdfium
 - add "seed" param to perlin, worley and gaussnoise
 
+18/12/20 started 8.10.5
+- fix potential /0 in animated webp load [lovell]
+
 14/12/20 started 8.10.4
 - fix spng detection
 
diff --git a/libvips/foreign/webp2vips.c b/libvips/foreign/webp2vips.c
index e0e91e99..38a59807 100644
--- a/libvips/foreign/webp2vips.c
+++ b/libvips/foreign/webp2vips.c
@@ -260,9 +260,9 @@ blend_pixel( guint32 A, guint32 B )
 
 	guint8 aB = getA( B );
 
-	guint8 fac = (aB * (256 - aA) + 128) >> 8;
+	guint8 fac = (aB * (255 - aA) + 127) >> 8;
 	guint8 aR =  aA + fac;
-	int scale = (1 << 24) / aR;
+	int scale = aR == 0 ? 0 : (1 << 24) / aR;
 
 	guint8 rR = BLEND( getR( A ), aA, getR( B ), fac, scale );
 	guint8 gR = BLEND( getG( A ), aA, getG( B ), fac, scale );
diff --git a/test/test-suite/helpers/helpers.py b/test/test-suite/helpers/helpers.py
index 8d1c309d..585a7f0c 100644
--- a/test/test-suite/helpers/helpers.py
+++ b/test/test-suite/helpers/helpers.py
@@ -22,6 +22,7 @@ ANALYZE_FILE = os.path.join(IMAGES, "t00740_tr1_segm.hdr")
 GIF_FILE = os.path.join(IMAGES, "cramps.gif")
 WEBP_FILE = os.path.join(IMAGES, "1.webp")
 WEBP_LOOKS_LIKE_SVG_FILE = os.path.join(IMAGES, "looks-like-svg.webp")
+WEBP_ANIMATED_FILE = os.path.join(IMAGES, "big-height.webp")
 EXR_FILE = os.path.join(IMAGES, "sample.exr")
 FITS_FILE = os.path.join(IMAGES, "WFPC2u5780205r_c0fx.fits")
 OPENSLIDE_FILE = os.path.join(IMAGES, "CMU-1-Small-Region.svs")
diff --git a/test/test-suite/images/big-height.webp b/test/test-suite/images/big-height.webp
new file mode 100644
index 00000000..752a1696
Binary files /dev/null and b/test/test-suite/images/big-height.webp differ
diff --git a/test/test-suite/test_foreign.py b/test/test-suite/test_foreign.py
index a0cb4966..b146c9bd 100644
--- a/test/test-suite/test_foreign.py
+++ b/test/test-suite/test_foreign.py
@@ -17,8 +17,8 @@ from helpers import \
     GIF_ANIM_DISPOSE_PREVIOUS_FILE, \
     GIF_ANIM_DISPOSE_PREVIOUS_EXPECTED_PNG_FILE, \
     temp_filename, assert_almost_equal_objects, have, skip_if_no, \
-    TIF1_FILE, TIF2_FILE, TIF4_FILE, WEBP_LOOKS_LIKE_SVG_FILE
-
+    TIF1_FILE, TIF2_FILE, TIF4_FILE, WEBP_LOOKS_LIKE_SVG_FILE, \
+    WEBP_ANIMATED_FILE
 
 class TestForeign:
     tempdir = None
@@ -694,6 +694,12 @@ class TestForeign:
             x = pyvips.Image.new_from_file(WEBP_LOOKS_LIKE_SVG_FILE)
             assert x.get("vips-loader") == "webpload"
 
+        # Animated WebP roundtrip
+        x = pyvips.Image.new_from_file(WEBP_ANIMATED_FILE, n=-1)
+        assert x.width == 13
+        assert x.height == 16393
+        buf = x.webpsave_buffer()
+
     @skip_if_no("analyzeload")
     def test_analyzeload(self):
         def analyze_valid(im):