From fd6867bc57081ae89429162ab9ee12b24c94898f Mon Sep 17 00:00:00 2001
From: Muaz Ahmad <mahmad2000@protonmail.com>
Date: Thu, 12 Oct 2023 14:21:20 +0500
Subject: [PATCH] av01 parsing

---
 mp4-tree.js | 55 ++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/mp4-tree.js b/mp4-tree.js
index 185e227..065d4b4 100644
--- a/mp4-tree.js
+++ b/mp4-tree.js
@@ -49,19 +49,21 @@ class MP4Tree {
 			if (!this.parse_until('trak')) { // if no more tracks in file
 				break;
 			}
-			const curr_track_end = this.idx + this.read_next_head().len;
+			let curr_track_end = this.idx + this.read_next_head().len;
 			this.idx += 8
 			this.parse_into('mdia', 8);
 			this.parse_into('minf', 8);
-			const track_type_head = this.read_next_head().name;
+			let track_type_head = this.read_next_head().name;
 			if (track_type_head == 'smhd' || track_type_head == 'vmhd') {
 				this.parse_into('stbl', 8);
 				this.parse_into('stsd', 16);
-				const media_sample = this.read_next_head().name;
+				let media_sample = this.read_next_head().name;
 				if (media_sample == 'avc1') {
 					this.parse_avc1();
 				} else if (media_sample == 'vp09') {
 					this.parse_vp09();
+				} else if (media_sample == 'av01') {
+					this.parse_av01();
 				} else if (media_sample == 'mp4a') {
 					this.parse_mp4a();
 				} else if (media_sample == 'Opus') {
@@ -80,27 +82,62 @@ class MP4Tree {
 		// ex, 01 64 00 1f
 		// 01 is avc version (always 1, bit-and it off)
 		// rest is video codec profile, rep as hex
-		const avc_profile = (this.data.getUint32(this.idx) & 0xffffff).toString(16); 
+		let avc_profile = (this.data.getUint32(this.idx) & 0xffffff).toString(16); 
 		this.codecs.push('avc1.' + avc_profile);
 	}
 
 	parse_vp09() {
 		this.parse_into('vp09', 86);
 		this.parse_into('vpcC', 12);
-		const profile = this.data.getUint8(this.idx).toString().padStart(2, "0");
-		const level = this.data.getUint8(this.idx + 1).toString();
-		const depth = (this.data.getUint8(this.idx + 2) >> 4).toString().padStart(2, "0");
+		let profile = this.data.getUint8(this.idx).toString().padStart(2, "0");
+		let level = this.data.getUint8(this.idx + 1).toString();
+		let depth = (this.data.getUint8(this.idx + 2) >> 4).toString().padStart(2, "0");
 		this.codecs.push(["vp09", profile, level, depth].join('.'));
 	}
 
+	parse_av01() {
+		this.parse_into('av01', 101);
+		this.parse_into('av1C', 8);
+		let tmp = this.data.getUint8(this.idx + 1);
+		let profile = tmp >> 5;
+		let level = tmp & 0x1f;
+		let tmp = this.data.getUint8(this.idx + 2);
+		switch (tmp >> 7) {
+			case 0:
+				let level_profile = "M";
+				break;
+			case 1:
+				let level_profile = "H";
+				break;
+			default:
+				let level_profile = "";
+		}
+		let depth_bits = (tmp >> 5) & 0x3;
+		switch (depth_bits) {
+			case 0:
+				let bit_depth = "8";
+				break;
+			case 1:
+				let bit_depth = "12";
+				break;
+			case 2:
+				let bit_depth = "10";
+				break;
+			default:
+				let bit_depth = "0";
+				break;
+		}
+		this.codecs.push(["av01", profile, level.toString().padStart(2, "0") + level_profile, bit_depth].join('.'))
+	}
+
 	parse_mp4a() {
 		this.parse_into('mp4a', 36); // 28 bytes of subboxes with unclear offsets
 		this.parse_into('esds', 12);
 		// mp4a is as mp4a.40.2
 		// oti has defined position, rep as hex
 		// aot as a subtype is defined as 5 bits of the fetched byte, rep as dec
-		const oti = this.data.getUint8(this.idx + 13).toString(16); 
-		const aot = (this.data.getUint8(this.idx + 31) >> 3).toString(10);
+		let oti = this.data.getUint8(this.idx + 13).toString(16); 
+		let aot = (this.data.getUint8(this.idx + 31) >> 3).toString(10);
 		this.codecs.push(["mp4a", oti, aot].join('.'));
 	}