ensure subsequent avifEncoderAddImage call passes compatible image

Author: tongyuantongyu

include/avif/avif.h

@@ -147,7 +147,8 @@ typedef enum avifResult
     AVIF_RESULT_INVALID_ARGUMENT, // an argument passed into this function is invalid
     AVIF_RESULT_NOT_IMPLEMENTED,  // a requested code path is not (yet) implemented
     AVIF_RESULT_OUT_OF_MEMORY,
-    AVIF_RESULT_CANNOT_CHANGE_SETTING // a setting that can't change is changed during encoding
+    AVIF_RESULT_CANNOT_CHANGE_SETTING, // a setting that can't change is changed during encoding
+    AVIF_RESULT_INCOMPATIBLE_IMAGE     // given image is not compatible with already encoded image
 } avifResult;
 
 AVIF_API const char * avifResultToString(avifResult result);

src/avif.c

@@ -97,6 +97,7 @@ const char * avifResultToString(avifResult result)
         case AVIF_RESULT_NOT_IMPLEMENTED:               return "Not implemented";
         case AVIF_RESULT_OUT_OF_MEMORY:                 return "Out of memory";
         case AVIF_RESULT_CANNOT_CHANGE_SETTING:         return "Can not change some settings during encoding";
+        case AVIF_RESULT_INCOMPATIBLE_IMAGE:            return "This image is incompatible with already encoded image";
         case AVIF_RESULT_UNKNOWN_ERROR:
         default:
             break;

src/write.c

@@ -863,10 +863,23 @@ static avifResult avifEncoderAddImageInternal(avifEncoder * encoder,
     } else {
         // Another frame in an image sequence
 
-        if (encoder->data->alphaPresent && !firstCell->alphaPlane) {
-            // If the first image in the sequence had an alpha plane (even if fully opaque), all
-            // subsequence images must have alpha as well.
-            return AVIF_RESULT_ENCODE_ALPHA_FAILED;
+        const avifImage * imageMetadata = encoder->data->imageMetadata;
+        // 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 the first image in the sequence had an alpha plane (even if fully opaque), all
+        // subsequence images must have alpha as well.
+        if ((imageMetadata->width != firstCell->width) || (imageMetadata->height != firstCell->height) ||
+            (imageMetadata->depth != firstCell->depth) || (imageMetadata->yuvFormat != firstCell->yuvFormat) ||
+            (imageMetadata->yuvRange != firstCell->yuvRange) || (imageMetadata->colorPrimaries != firstCell->colorPrimaries) ||
+            (imageMetadata->transferCharacteristics != firstCell->transferCharacteristics) ||
+            (imageMetadata->matrixCoefficients != firstCell->matrixCoefficients) ||
+            (!!imageMetadata->alphaPlane != !!firstCell->alphaPlane) ||
+            (imageMetadata->alphaPremultiplied != firstCell->alphaPremultiplied) ||
+            (encoder->data->alphaPresent && !firstCell->alphaPlane)) {
+            return AVIF_RESULT_INCOMPATIBLE_IMAGE;
         }
     }