add support for Dolby Vision

Author: paulhiggs

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "codec-string",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "decode the codecs= string in a media mime type",
   "type": "module",
   "engines": {

package.json

@@ -0,0 +1,86 @@
+/**
+ * @copyright: Copyright (c) 2025
+ * @author: Paul Higgs
+ * @file: decode-dolby.js
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+import { simpleHTML } from './formatters.js';
+import { expressions } from './regular_expressions.js';
+import { normal, error } from './decode.js';
+
+ const DEBUGGING = false;
+
+// See DolbyVisionProfileLevels.pdf - available at https://dolby.my.salesforce.com/sfc/dist/version/download/?oid=00D700000009YuG&ids=068QQ00000bpfevYAA&d=/a/4u000000B3Ig/8qhPH.ETus3SaczpT9twKYXsYUtwstZpjlev3DBll.I&operationContext=DELIVERY&viewId=05HQQ00000ThR5t2AF&dpt=
+// and DolbyVisionInMPEGDASHSpecification.pdf - available at https://dolby.my.salesforce.com/sfc/dist/version/download/?oid=00D700000009YuG&ids=0684u00000V1DFXAA3&d=/a/4u000000l6FV/TqYPD0f0c3Zm40JJrFKFn1m29QdUxuVB.U_GzZzbXgE&operationContext=DELIVERY&viewId=05HQQ00000ThX6T2AV&dpt=
+
+export function decodeDolbyVision(val) {
+	if (!expressions.DolbyVision.regex.test(val)) return [error('Regex mismatch!'), error(expressions.DolbyVision.format)];
+	const parts = val.split('.');
+	// this check should not fail as the number of parts and the format are checked in the regular expression
+	if (parts.length != 3) return [error(`DolbyVision format is "${expressions.AC4.format}"`)];
+
+	const profile = parseInt(parts[1]),
+		level = parseInt(parts[2]);
+
+	let res = [];
+
+	switch (parts[0]) {
+		case 'dvhe':
+			res.push(normal('HEVC-based Dolby Vision codec.'));
+			res.push(normal('Parameter sets (VPS, PPS, or SPS) are stored either in the sample entries or as part of the samples, or in both.'));
+			break;
+		case 'dvh1':
+			res.push(normal('HEVC-based Dolby Vision codec.'));
+			res.push(normal('Parameter sets (VPS, PPS, or SPS) are stored in the sample entries only.'));
+			break;
+		case 'dvav':
+			res.push(normal('AVC-based Dolby Vision codec.'));
+			res.push(normal('Parameter sets (PPS or SPS) are stored either in the sample entries or as part of the samples, or in both.'));
+			break;
+		case 'dva1':
+			res.push(normal('AVC-based Dolby Vision codec.'));
+			res.push(normal('Parameter sets (PPS or SPS) are stored either in the sample entries of the video stream or in the parameter set stream, but never in both.'));
+			break;
+	}
+
+	res.push([5,7,8,9,20].includes(profile)
+		? normal(`Bitstream Profile ID: ${parts[1]}`)
+		: error(`Unrecognised bitstream_profile_id (${parts[1]})`)
+	);
+
+	res.push((level >= 1 && level <=13) 
+		? normal(`Level ID: ${parts[2]}`)
+		: error(`Unrecognised level_id (${parts[2]})`)
+	);
+
+	return res;
+}
+
+
+ export function registerDolbyVision(addHandler) {
+	const outputHTML = (label, messages) => simpleHTML(label, messages, DEBUGGING);
+ 
+	addHandler(['dvhe', 'dvh1', 'dvav', 'dva1'], 'Dolby Vision stream', decodeDolbyVision, outputHTML);
+ }

src/decode-dolby.js

@@ -79,7 +79,7 @@ class parsing {
 	setResult(result) {
 		if (Array.isArray(result)) this.parsed = result;
 		else if (typeof result == 'string') this.parsed = [].push(result);
-		else this.parsed = [error('failed to interpret deciding result')];
+		else this.parsed = [error('failed to interpret decoding result')];
 	}
 
 	toHTML() {

src/decode.js

@@ -2,6 +2,7 @@ import { registerAC4 } from './decode-ac4.js';
 import { registerAOM } from './decode-aom.js';
 import { registerAVC } from './decode-avc.js';
 import { registerAVS3 } from './decode-avs.js';
+import { registerDolbyVision } from './decode-dolby.js';
 import { registerDTS } from './decode-dts.js';
 import { registerEVC } from './decode-evc.js';
 import { registerHEVC } from './decode-hevc.js';
@@ -44,6 +45,7 @@ const registerFactories = [
 	registerAOM,
 	registerAVC,
 	registerAVS3,
+	registerDolbyVision,
 	registerDTS,
 	registerEVC,
 	registerHEVC,

src/handler.js

@@ -2,6 +2,7 @@ const { decodeAC4 } = require('./decode-ac4.js');
 const { decodeAV1, decodeIAMF } = require('./decode-aom.js');
 const { decodeAVC } = require('./decode-avc.js');
 const { decodeAVS3, decodeAVS3audio, decodeAVS2audio } = require('./decode-avs.js');
+const { decodeDolbyVision } = require('./decode-dolby.js');
 const { decodeDTS } = require('./decode-dts.js');
 const { decodeEVC } = require('./decode-evc.js');
 const { decodeHEVC } = require('./decode-hevc.js');
@@ -24,6 +25,7 @@ module.exports = {
 	decodeAVS3,
 	decodeAVS3audio,
 	decodeAVS2audio,
+	decodeDolbyVision,
 	decodeDTS,
 	decodeEVC,
 	decodeHEVC,

src/index.cjs

@@ -2,6 +2,7 @@ export { decodeAC4 } from './decode-ac4.js';
 export { decodeAV1, decodeIAMF } from './decode-aom.js';
 export { decodeAVC } from './decode-avc.js';
 export { decodeAVS3, decodeAVS3audio, decodeAVS2audio } from './decode-avs.js';
+export { decodeDolbyVision } from './decode-dolby.js';
 export { decodeDTS } from './decode-dts.js';
 export { decodeEVC } from './decode-evc.js';
 export { decodeHEVC } from './decode-hevc.js';

src/index.js

@@ -53,12 +53,16 @@ export const expressions = {
 	AVS3audio: {
 		regex: /av3a\.[a-fA-F\d]{1,2}$/,
 		format: "av3a.<codec_id>",
-		description: "codec_is is 0 for general high rate coding, 1 for lossless, 2 for general full rate coding"
+		description: "codec_id is 0 for general high rate coding, 1 for lossless, 2 for general full rate coding"
 	},
 	AVS2audio: { 
 		regex: /cavs\.[a-fA-F\d]{1,2}$/,
 		format: "cavs.<codec_id>",
-		description: "codec_is is 0 for general high rate coding, 1 for lossless"
+		description: "codec_id is 0 for general high rate coding, 1 for lossless"
+	},
+	DolbyVision: {
+		regex: /^(dvav|dvhe|dvh1|dva1)\.\d{2}\.\d{2}$/,
+		format: "[Codec_type].[bitstream_profile_ID].[Dolby_Vision_Level_ID]"
 	},
 	VP9: {
 		regex: /^vp09(\.\d{2}){3}(\.(\d{2})?){0,5}$/,