diff --git a/CHANGELOG.md b/CHANGELOG.md
index fd4b535..8be96cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 All notable changes to this project will be documented in this file.
 
+## [1.1.6] - 2023-10-25
+
+### Changed
+
+- codecs: Special handling for mp3 streams inside mp4 containers.
+- codecs: Handle ffprobe level -99 in mp4 files.
+
 ## [1.1.5] - 2023-10-22
 
 ### Changed
diff --git a/codecs/codecs.js b/codecs/codecs.js
index d3fc265..169ad82 100644
--- a/codecs/codecs.js
+++ b/codecs/codecs.js
@@ -141,6 +141,12 @@ export function getFullMIMEString(info) {
 
   for (const stream of info.streams) {
     if (stream.codec_type === 'audio') {
+      // MP3 can sometimes have codec_tag_string=mp4a, so we check for it first.
+      if (stream.codec_name === 'mp3') {
+        codecFrags.add('mp3');
+        continue;
+      }
+
       switch (stream.codec_tag_string) {
         case 'mp4a': codecFrags.add(getMP4ACodecString(stream)); break;
         default: 
@@ -267,8 +273,8 @@ function getVP09CodecString(stream) {
   }
 
   // Add LL hex digits.
-  // If ffprobe is spitting out -99 as level... Just return 'vp9'.
-  if (stream.level === -99) { return 'vp9'; }
+  // If ffprobe is spitting out -99 as level... it means unknown, so we will guess level=1.
+  if (stream.level === -99) { frag += `.10`; }
   else {
     const levelAsHex = Number(stream.level).toString(16).toUpperCase().padStart(2, '0');
     if (levelAsHex.length !== 2) {
@@ -279,8 +285,8 @@ function getVP09CodecString(stream) {
   }
 
   // Add DD hex digits.
-  // TODO: This is just a guess at DD (16?), need to try and extract this info from
-  //     ffprobe JSON output instead.
+  // TODO: This is just a guess at DD (10-bit color depth), need to try and extract this info
+  //     from ffprobe JSON output instead.
   frag += '.10';
 
   return frag;
diff --git a/package.json b/package.json
index 63ded57..e3283e4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@codedread/bitjs",
-  "version": "1.1.5",
+  "version": "1.1.6",
   "description": "Binary Tools for JavaScript",
   "homepage": "https://github.com/codedread/bitjs",
   "author": "Jeff Schiller",
diff --git a/tests/codecs.spec.js b/tests/codecs.spec.js
index 0d25f17..a2a94ae 100644
--- a/tests/codecs.spec.js
+++ b/tests/codecs.spec.js
@@ -349,11 +349,11 @@ describe('codecs test suite', () => {
               });
           });
   
-        it('detects level = -99', () => {
-          info.streams[0].level = -99; // I'm not sure what ffprobe means by this.
+        it('detects level = -99 as level 1', () => {
+          info.streams[0].level = -99; // I believe this is the "unknown" value from ffprobe.
           expect(getFullMIMEString(info))
               .to.be.a('string')
-              .and.equals('video/webm; codecs="vp9"');
+              .and.equals('video/webm; codecs="vp09.00.10.10"');
         });
       });
   
@@ -575,6 +575,18 @@ describe('codecs test suite', () => {
     });
   });
 
+  describe('MP3', () => {
+    it('detects MP3', () => {
+      /** @type {ProbeInfo} */
+      let info = {
+        format: { format_name: 'mov,mp4,m4a,3gp,3g2,mj2' },
+        streams: [ { codec_type: 'audio', codec_name: 'mp3', codec_tag_string: 'mp4a' } ],
+      };
+      expect(getShortMIMEString(info)).equals('audio/mp4');
+      expect(getFullMIMEString(info)).equals('audio/mp4; codecs="mp3"');
+    });
+  });
+
   describe('WAV', () => {
     it('detects WAV', () => {
       /** @type {ProbeInfo} */