commit bf28a923b6aa2647d27145db41f222c83e25d715
author Yannis Guyon <51164219+y-guyon@users.noreply.github.com> Wed Feb 09 23:19:32 2022 +0100
committer GitHub <noreply@github.com> Wed Feb 09 14:19:32 2022 -0800
tree 8e35f3d625928438d3d57b7da9a86c490d803bf2
parent 91bc33a6bd761f70013d7f0f041262626e1d5cad

Move checks to avifAreGridDimensionsValid() (#834)

It was possible to encode a 65x65 4:2:0 image with avifenc that could
not be decoded with avifdec. Calling avifAreGridDimensionsValid() from
both encoding and decoding pipelines removes this asymmetric behavior.

Add tests/avifgridapitest.c.

src/write.c

diff --git a/src/write.c b/src/write.c
index 657bfaa..cd0a274 100644
--- a/src/write.c
+++ b/src/write.c
@@ -567,15 +567,28 @@
         return AVIF_RESULT_NO_CONTENT;
     }
 
-    if ((cellCount > 1) && ((firstCell->width < 64) || (firstCell->height < 64))) {
+    if ((cellCount > 1) && !avifAreGridDimensionsValid(firstCell->yuvFormat,
+                                                       gridCols * firstCell->width,
+                                                       gridRows * firstCell->height,
+                                                       firstCell->width,
+                                                       firstCell->height,
+                                                       &encoder->diag)) {
         return AVIF_RESULT_INVALID_IMAGE_GRID;
     }
 
     for (uint32_t cellIndex = 0; cellIndex < cellCount; ++cellIndex) {
         const avifImage * cellImage = cellImages[cellIndex];
-        if ((cellImage->depth != firstCell->depth) || (cellImage->width != firstCell->width) ||
-            (cellImage->height != firstCell->height) || (!!cellImage->alphaPlane != !!firstCell->alphaPlane) ||
-            (cellImage->alphaPremultiplied != firstCell->alphaPremultiplied)) {
+        // HEIF (ISO 23008-12:2017), Section 6.6.2.3.1:
+        //   All input images shall have exactly the same width and height; call those tile_width and tile_height.
+        // MIAF (ISO 23000-22:2019), Section 7.3.11.4.1:
+        //   All input images of a grid image item shall use the same coding format, chroma sampling format, and the
+        //   same decoder configuration (see 7.3.6.2).
+        if ((cellImage->width != firstCell->width) || (cellImage->height != firstCell->height) ||
+            (cellImage->depth != firstCell->depth) || (cellImage->yuvFormat != firstCell->yuvFormat) ||
+            (cellImage->yuvRange != firstCell->yuvRange) || (cellImage->colorPrimaries != firstCell->colorPrimaries) ||
+            (cellImage->transferCharacteristics != firstCell->transferCharacteristics) ||
+            (cellImage->matrixCoefficients != firstCell->matrixCoefficients) || (cellImage->alphaRange != firstCell->alphaRange) ||
+            (!!cellImage->alphaPlane != !!firstCell->alphaPlane) || (cellImage->alphaPremultiplied != firstCell->alphaPremultiplied)) {
             return AVIF_RESULT_INVALID_IMAGE_GRID;
         }