Changes to comments and CHANGELOG.md

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 833b4b5..a65ec69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 ## [Unreleased]
 
 ### Changed
+* Mandate ispe and disallow zero width or height (#640).
 * Re-map libavif speed 7-10 to libaom speed 7-9 (#682)
 *  Refer to https://aomedia-review.googlesource.com/c/aom/+/140624
 *  If you were using libaom with the following avif speed setting:

src/codec_aom.c

diff --git a/src/codec_aom.c b/src/codec_aom.c
index 922fa40..7301ebb 100644
--- a/src/codec_aom.c
+++ b/src/codec_aom.c
@@ -127,6 +127,7 @@
         nextFrame = aom_codec_get_frame(&codec->internal->decoder, &codec->internal->iter);
         if (nextFrame) {
             if (spatialID != AVIF_SPATIAL_ID_UNSET) {
+                // This requires a version of libaom with the fix for https://crbug.com/aomedia/2993.
                 if (spatialID == nextFrame->spatial_id) {
                     // Found the correct spatial_id.
                     break;

src/scale.c

diff --git a/src/scale.c b/src/scale.c
index 528370f..69438cb 100644
--- a/src/scale.c
+++ b/src/scale.c
@@ -25,7 +25,7 @@
 #pragma clang diagnostic pop
 #endif
 
-// This should be configurable and/or smarter
+// This should be configurable and/or smarter. kFilterBox has the highest quality but is the slowest.
 #define AVIF_LIBYUV_FILTER_MODE kFilterBox
 
 avifBool avifImageScale(avifImage * image, uint32_t dstWidth, uint32_t dstHeight, avifDiagnostics * diag)