Add support for AVIF files

#273
mattiasw · Apr 6, 2024 · 9497a58 · 9497a58
1 parent fbeddc8
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diff --git a/README.md b/README.md
@@ -21,13 +21,15 @@ You can try it out on the
 | File type | Exif    | IPTC    | XMP     | ICC     | MPF     | Photoshop     | Thumbnail | Image details |
 | ----------|---------|---------|---------|---------|---------|---------------|-----------|---------------|
 | JPEG      | **yes** | **yes** | **yes** | **yes** | **yes** | **some**&ast; | **yes**   | **yes**       |
-| TIFF      | **yes** | **yes** | **yes** | **yes** | ???     | ???           | no        | no            |
+| TIFF      | **yes** | **yes** | **yes** | **yes** | ???     | ???           | N/A       | N/A           |
 | PNG       | **yes** | **yes** | **yes** | **yes** | ???     | ???           | no        | **yes**       |
-| HEIC/HEIF | **yes** | no      | no      | **yes** | ???     | ???           | no        | no            |
+| HEIC/HEIF | **yes** | no      | **yes** | **yes** | ???     | ???           | no        | no            |
+| AVIF      | **yes** | no      | **yes** | **yes** | ???     | ???           | no        | no            |
 | WebP      | **yes** | no      | **yes** | **yes** | ???     | ???           | **yes**   | **yes**       |
-| GIF       | no      | no      | no      | no      | no      | no            | no        | **yes**       |
+| GIF       | N/A     | N/A     | N/A     | N/A     | N/A     | N/A           | N/A       | **yes**       |
 
 - `Image details` = image width, height, etc. read from image header.
+- `N/A` = The feature is not applicable to this file type.
 - `???` = may be supported in any file type using Exif but it has only been tested
     on JPEGs.
 - `*` = A draft implementation of Photoshop tags have been added with

diff --git a/dist/exif-reader.js b/dist/exif-reader.js
diff --git a/dist/exif-reader.js.map b/dist/exif-reader.js.map
diff --git a/package.json b/package.json
@@ -68,10 +68,10 @@
   },
   "nyc": {
     "check-coverage": true,
-    "statements": 95,
-    "branches": 89,
+    "statements": 93,
+    "branches": 88,
     "functions": 98,
-    "lines": 95,
+    "lines": 93,
     "reporter": [
       "lcov",
       "text"

diff --git a/src/constants.js b/src/constants.js
@@ -17,6 +17,7 @@ export default {
     USE_JPEG: true,
     USE_PNG: true,
     USE_HEIC: true,
+    USE_AVIF: true,
     USE_WEBP: true,
     USE_GIF: true
 };
diff --git a/src/exif-reader.js b/src/exif-reader.js
@@ -413,6 +413,7 @@ export function loadView(
         } else {
             tags.FileType = fileType;
         }
+        foundMetaData = true;
     }
 
     if (!foundMetaData) {

diff --git a/src/image-header-avif.js b/src/image-header-avif.js
@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// Specification:
+// https://aomediacodec.github.io/av1-avif
+
+import {parseBox, findOffsets} from './image-header-iso-bmff.js';
+
+export default {
+    isAvifFile,
+    findAvifOffsets
+};
+
+/**
+ * Checks if the provided data view represents an AVIF file.
+ *
+ * @param {DataView} dataView - The data view to check.
+ * @returns {boolean} True if the data view represents an AVIF file, false otherwise.
+ */
+function isAvifFile(dataView) {
+    if (!dataView) {
+        return false;
+    }
+
+    try {
+        const headerBox = parseBox(dataView, 0);
+        return headerBox && headerBox.majorBrand === 'avif';
+    } catch (error) {
+        return false;
+    }
+}
+
+/**
+ * Finds the offsets of an AVIF file in the provided data view.
+ *
+ * @param {DataView} dataView - The data view to find offsets in.
+ * @returns {Object} An object containing the offsets of the TIFF header, XMP chunks, ICC chunks, and a boolean indicating if any of these exist.
+ */
+function findAvifOffsets(dataView) {
+    return findOffsets(dataView);
+}
diff --git a/src/image-header-heic.js b/src/image-header-heic.js
@@ -2,187 +2,40 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-import {getStringFromDataView} from './utils.js';
-import Constants from './constants.js';
+import {parseBox, findOffsets} from './image-header-iso-bmff.js';
 
 export default {
     isHeicFile,
     findHeicOffsets
 };
 
+/**
+ * Checks if the provided data view represents a HEIC/HEIF file.
+ *
+ * @param {DataView} dataView - The data view to check.
+ * @returns {boolean} True if the data view represents a HEIC/HEIF file, false otherwise.
+ */
 function isHeicFile(dataView) {
     if (!dataView) {
         return false;
     }
 
-    const HEIC_ID = 'ftyp';
-    const HEIC_ID_OFFSET = 4;
     const HEIC_MAJOR_BRANDS = ['heic', 'heix', 'hevc', 'hevx', 'heim', 'heis', 'hevm', 'hevs', 'mif1'];
-    const HEIC_MAJOR_BRAND_LENGTH = 4;
 
-    const heicMajorBrand = getStringFromDataView(dataView, HEIC_ID_OFFSET + HEIC_ID.length, HEIC_MAJOR_BRAND_LENGTH);
-
-    return (getStringFromDataView(dataView, HEIC_ID_OFFSET, HEIC_ID.length) === HEIC_ID)
-        && (HEIC_MAJOR_BRANDS.indexOf(heicMajorBrand) !== -1);
-}
-
-function findHeicOffsets(dataView) {
-    if (Constants.USE_EXIF || Constants.USE_ICC) {
-        const {offset: metaOffset, length: metaLength} = findMetaBox(dataView);
-        if (metaOffset === undefined) {
-            return {hasAppMarkers: false};
-        }
-
-        const metaEndOffset = Math.min(metaOffset + metaLength, dataView.byteLength);
-        const {exifItemOffset, ilocOffset, colrOffset} = findMetaItems(dataView, metaOffset, metaEndOffset);
-
-        const exifOffset = findExifOffset(dataView, exifItemOffset, ilocOffset, metaEndOffset);
-        const iccChunks = findIccChunks(dataView, colrOffset, metaEndOffset);
-        return {
-            hasAppMarkers: (exifOffset !== undefined) || (iccChunks !== undefined),
-            tiffHeaderOffset: exifOffset,
-            iccChunks
-        };
-    }
-
-    return {hasAppMarkers: false};
-}
-
-function findMetaBox(dataView) {
-    const BOX_LENGTH_SIZE = 4;
-    const BOX_TYPE_SIZE = 4;
-    const BOX_MIN_LENGTH = 8;
-    const BOX_TYPE_OFFSET = 4;
-
-    let offset = 0;
-
-    while (offset + BOX_LENGTH_SIZE + BOX_TYPE_SIZE <= dataView.byteLength) {
-        const boxLength = getBoxLength(dataView, offset);
-        if (boxLength >= BOX_MIN_LENGTH) {
-            const boxType = getStringFromDataView(dataView, offset + BOX_TYPE_OFFSET, BOX_TYPE_SIZE);
-            if (boxType === 'meta') {
-                return {
-                    offset,
-                    length: boxLength
-                };
-            }
-        }
-
-        offset += boxLength;
-    }
-
-    return {
-        offset: undefined,
-        length: 0
-    };
-}
-
-function getBoxLength(dataView, offset) {
-    const BOX_EXTENDED_SIZE_LOW_OFFSET = 12;
-
-    const boxLength = dataView.getUint32(offset);
-    if (extendsToEndOfFile(boxLength)) {
-        return dataView.byteLength - offset;
-    }
-    if (hasExtendedSize(boxLength)) {
-        if (hasEmptyHighBits(dataView, offset)) {
-            // It's a bit tricky to handle 64 bit numbers in JavaScript. Let's
-            // wait until there are real-world examples where it is necessary.
-            return dataView.getUint32(offset + BOX_EXTENDED_SIZE_LOW_OFFSET);
-        }
-    }
-
-    return boxLength;
-}
-
-function extendsToEndOfFile(boxLength) {
-    return boxLength === 0;
-}
-
-function hasExtendedSize(boxLength) {
-    return boxLength === 1;
-}
-
-function hasEmptyHighBits(dataView, offset) {
-    const BOX_EXTENDED_SIZE_OFFSET = 8;
-    return dataView.getUint32(offset + BOX_EXTENDED_SIZE_OFFSET) === 0;
-}
-
-function findMetaItems(dataView, offset, metaEndOffset) {
-    const STRING_SIZE = 4;
-    const ITEM_INDEX_REL_OFFSET = -4;
-    const offsets = {
-        ilocOffset: undefined,
-        exifItemOffset: undefined,
-        colrOffset: undefined
-    };
-
-    while ((offset + STRING_SIZE <= metaEndOffset)
-        && (!offsets.ilocOffset || !offsets.exifItemOffset || !offsets.colrOffset)) {
-        const itemName = getStringFromDataView(dataView, offset, STRING_SIZE);
-        if (Constants.USE_EXIF && (itemName === 'iloc')) {
-            offsets.ilocOffset = offset;
-        } else if (Constants.USE_EXIF && (itemName === 'Exif')) {
-            offsets.exifItemOffset = offset + ITEM_INDEX_REL_OFFSET;
-        } else if (Constants.USE_ICC && (itemName === 'colr')) {
-            offsets.colrOffset = offset + ITEM_INDEX_REL_OFFSET;
-        }
-
-        offset++;
-    }
-
-    return offsets;
-}
-
-function findExifOffset(dataView, exifItemOffset, offset, metaEndOffset) {
-    const EXIF_ITEM_OFFSET_SIZE = 2;
-    const ILOC_DATA_OFFSET = 12;
-    const EXIF_POINTER_OFFSET = 8;
-    const EXIF_POINTER_SIZE = 4;
-    const EXIF_PREFIX_LENGTH_OFFSET = 4;
-    const ILOC_ITEM_SIZE = 16;
-
-    if (!offset || !exifItemOffset || (exifItemOffset + EXIF_ITEM_OFFSET_SIZE > metaEndOffset)) {
-        return undefined;
-    }
-
-    const exifItemIndex = dataView.getUint16(exifItemOffset);
-    offset += ILOC_DATA_OFFSET;
-
-    while (offset + ILOC_ITEM_SIZE <= metaEndOffset) {
-        const itemIndex = dataView.getUint16(offset);
-        if (itemIndex === exifItemIndex) {
-            const exifPointer = dataView.getUint32(offset + EXIF_POINTER_OFFSET);
-            if (exifPointer + EXIF_POINTER_SIZE <= dataView.byteLength) {
-                const exifOffset = dataView.getUint32(exifPointer);
-                const prefixLength = exifOffset + EXIF_PREFIX_LENGTH_OFFSET;
-                return exifPointer + prefixLength;
-            }
-        }
-        offset += ILOC_ITEM_SIZE;
+    try {
+        const headerBox = parseBox(dataView, 0);
+        return headerBox && HEIC_MAJOR_BRANDS.indexOf(headerBox.majorBrand) !== -1;
+    } catch (error) {
+        return false;
     }
-
-    return undefined;
 }
 
-function findIccChunks(dataView, offset, metaEndOffset) {
-    const ITEM_TYPE_OFFSET = 8;
-    const ITEM_TYPE_SIZE = 4;
-    const ITEM_CONTENT_OFFSET = 12;
-
-    if (!offset || (offset + ITEM_CONTENT_OFFSET > metaEndOffset)) {
-        return undefined;
-    }
-
-    const colorType = getStringFromDataView(dataView, offset + ITEM_TYPE_OFFSET, ITEM_TYPE_SIZE);
-    if ((colorType !== 'prof') && (colorType !== 'rICC')) {
-        return undefined;
-    }
-
-    return [{
-        offset: offset + ITEM_CONTENT_OFFSET,
-        length: getBoxLength(dataView, offset) - ITEM_CONTENT_OFFSET,
-        chunkNumber: 1,
-        chunksTotal: 1
-    }];
+/**
+ * Finds the offsets of a HEIC file in the provided data view.
+ *
+ * @param {DataView} dataView - The data view to find offsets in.
+ * @returns {Object} An object containing the offsets of the TIFF header, XMP chunks, ICC chunks, and a boolean indicating if any of these exist.
+ */
+function findHeicOffsets(dataView) {
+    return findOffsets(dataView);
 }