commit 84dab6e3d0003facc3243898f034550103ce9572
author Wan-Teh Chang <wtc@google.com> Tue Jan 24 09:37:42 2023 -0800
committer Wan-Teh Chang <wtc@google.com> Fri Jan 27 01:54:41 2023 -0800
tree febc173f62cc6df4548a72d7de8ea83618f95d28
parent d642004c9992df7cf7870408066198eb7c4dd632

Increment currentLayer only after all uses of it

codec->internal->currentLayer is used in aomCodecEncodeImage() in four
places. Right now we increment codec->internal->currentLayer after the
second use, so the third and four uses see a value that is greater than
the correct value by one.

Fix this by incrementing codec->internal->currentLayer only after all
uses of it, right before we return AVIF_RESULT_OK at the end of
aomCodecEncodeImage().

src/codec_aom.c

diff --git a/src/codec_aom.c b/src/codec_aom.c
index 6f95265..dc31860 100644
--- a/src/codec_aom.c
+++ b/src/codec_aom.c
@@ -915,7 +915,6 @@
     }
     if (encoder->extraLayerCount > 0) {
         aom_codec_control(&codec->internal->encoder, AOME_SET_SPATIAL_LAYER_ID, codec->internal->currentLayer);
-        ++codec->internal->currentLayer;
     }
 
     aom_scaling_mode_t aomScalingMode;
@@ -1103,7 +1102,7 @@
     }
 
     if ((addImageFlags & AVIF_ADD_IMAGE_FLAG_SINGLE) ||
-        ((encoder->extraLayerCount > 0) && (encoder->extraLayerCount + 1 == codec->internal->currentLayer))) {
+        ((encoder->extraLayerCount > 0) && (encoder->extraLayerCount == codec->internal->currentLayer))) {
         // Flush and clean up encoder resources early to save on overhead when encoding alpha or grid images,
         // as encoding is finished now. For layered image, encoding finishes when the last layer is encoded.
 
@@ -1113,6 +1112,9 @@
         aom_codec_destroy(&codec->internal->encoder);
         codec->internal->encoderInitialized = AVIF_FALSE;
     }
+    if (encoder->extraLayerCount > 0) {
+        ++codec->internal->currentLayer;
+    }
     return AVIF_RESULT_OK;
 }