Identify AVIF files

src/ImageSharp/Formats/Heic/Heic4CharCode.cs

@@ -78,6 +78,11 @@ public enum Heic4CharCode : uint
     /// </summary>
     hvcC = 0x68766343U,
 
+    /// <summary>
+    /// AV1 configuration.
+    /// </summary>
+    av1C = 0x61763143U,
+
     /// <summary>
     /// Image Mirror.
     /// </summary>
@@ -143,6 +148,11 @@ public enum Heic4CharCode : uint
     /// </summary>
     mif1 = 0x6D696631U,
 
+    /// <summary>
+    /// AVIF brand.
+    /// </summary>
+    avif = 0x61766966U,
+
     /// <summary>
     /// High Efficiency Coding tile.
     /// </summary>
@@ -153,6 +163,11 @@ public enum Heic4CharCode : uint
     /// </summary>
     jpeg = 0x6A706567U,
 
+    /// <summary>
+    /// AOMedia Video Coding tile.
+    /// </summary>
+    av01 = 0x61763031U,
+
     /// <summary>
     /// Data Information.
     /// </summary>

src/ImageSharp/Formats/Heic/Heic4CharCode.tt

@@ -20,6 +20,7 @@
         "altt", "Alternative text",
         "colr", "Colour information",
         "hvcC", "HVC configuration",
+        "av1C", "AV1 configuration",
         "imir", "Image Mirror",
         "irot", "Image Rotation",
         "iscl", "Image Scaling",
@@ -33,8 +34,10 @@
         "heic", "High Efficient Image Coding brand",
         "heix", "High Efficient Image Coding brand (legacy name)",
         "mif1", "High Efficient File brand",
+        "avif", "AVIF brand",
         "hvc1", "High Efficiency Coding tile",
         "jpeg", "Legacy JPEG coded tile",
+        "av01", "AOMedia Video Coding tile",
         "dinf", "Data Information",
         "grpl", "Group list",
         "hdlr", "Handler",

src/ImageSharp/Formats/Heic/HeicDecoderCore.cs

@@ -131,10 +131,17 @@ internal sealed class HeicDecoderCore : IImageDecoderInternals
         }
 
         HeicMetadata meta = this.metadata.GetHeicMetadata();
-        if (this.itemLinks.Any(link => link.Type == Heic4CharCode.thmb))
+        HeicCompressionMethod compressionMethod = HeicCompressionMethod.Hevc;
+        if (item.Type == Heic4CharCode.av01)
         {
-            meta.CompressionMethod = HeicCompressionMethod.LegacyJpeg;
+            compressionMethod = HeicCompressionMethod.Av1;
         }
+        else if (this.itemLinks.Any(link => link.Type == Heic4CharCode.thmb))
+        {
+            compressionMethod = HeicCompressionMethod.LegacyJpeg;
+        }
+
+        meta.CompressionMethod = compressionMethod;
 
         return new ImageInfo(new PixelTypeInfo(item.BitsPerPixel), new(item.Extent.Width, item.Extent.Height), this.metadata);
     }
@@ -436,6 +443,7 @@ internal sealed class HeicDecoderCore : IImageDecoderInternals
                 case Heic4CharCode.irot:
                 case Heic4CharCode.iscl:
                 case Heic4CharCode.hvcC:
+                case Heic4CharCode.av1C:
                 case Heic4CharCode.rloc:
                 case Heic4CharCode.udes:
                     // TODO: Implement

src/ImageSharp/Formats/Heic/HeicImageFormatDetector.cs

@@ -25,6 +25,6 @@ public sealed class HeicImageFormatDetector : IImageFormatDetector
     {
         bool hasFtyp = BinaryPrimitives.ReadUInt32BigEndian(header.Slice(4)) == (uint)Heic4CharCode.ftyp;
         uint brand = BinaryPrimitives.ReadUInt32BigEndian(header.Slice(8));
-        return hasFtyp && (brand == (uint)Heic4CharCode.heic || brand == (uint)Heic4CharCode.heix);
+        return hasFtyp && (brand == (uint)Heic4CharCode.heic || brand == (uint)Heic4CharCode.heix || brand == (uint)Heic4CharCode.avif);
     }
 }

tests/ImageSharp.Tests/Formats/Heic/HeicDecoderTests.cs

@@ -14,6 +14,7 @@ public class HeicDecoderTests
     [InlineData(TestImages.Heic.Image1, HeicCompressionMethod.Hevc)]
     [InlineData(TestImages.Heic.Sample640x427, HeicCompressionMethod.Hevc)]
     [InlineData(TestImages.Heic.FujiFilmHif, HeicCompressionMethod.LegacyJpeg)]
+    [InlineData(TestImages.Heic.IrvineAvif, HeicCompressionMethod.Av1)]
     public void Identify(string imagePath, HeicCompressionMethod compressionMethod)
     {
         TestFile testFile = TestFile.Create(imagePath);