diff --git a/codecs/codecs.js b/codecs/codecs.js
index d972e06..05a994f 100644
--- a/codecs/codecs.js
+++ b/codecs/codecs.js
@@ -119,6 +119,14 @@ export function getFullMIMEString(info) {
         // TODO: vorbis.
         // TODO: opus.
         default: 
+          switch (stream.codec_name) {
+            case 'aac': codecFrags.add(getMP4ACodecString(stream)); break;
+            default:
+              throw `Could not handle codec_name ${stream.codec_name}, ` +
+                    `codec_tag_string ${stream.codec_tag_string} for file ${info.filename} yet. ` +
+                    `Please file a bug https://github.com/codedread/bitjs/issues/new`;
+          }
+          break;
       }
     }
     else if (stream.codec_type === 'video') {
@@ -130,8 +138,14 @@ export function getFullMIMEString(info) {
         case 'mjpeg':
           continue;
         default:
-          throw `Could not handle codec_tag_string ${stream.codec_tag_string} yet. ` +
-              `Please file a bug https://github.com/codedread/bitjs/issues/new`;
+          switch (stream.codec_name) {
+            case 'h264': codecFrags.add(getAVC1CodecString(stream)); break;
+            default:
+              throw `Could not handle codec_name ${stream.codec_name}, ` +
+                    `codec_tag_string ${stream.codec_tag_string} for file ${info.filename} yet. ` +
+                    `Please file a bug https://github.com/codedread/bitjs/issues/new`;
+
+          }
       }
     }
   }
@@ -143,6 +157,7 @@ export function getFullMIMEString(info) {
 // TODO: Consider whether any of these should be exported.
 
 /**
+ * AVC1 is the same thing as H264.
  * https://developer.mozilla.org/en-US/docs/Web/Media/Formats/codecs_parameter#iso_base_media_file_format_mp4_quicktime_and_3gp
  * @param {ProbeStream} stream
  * @returns {string}
@@ -237,6 +252,7 @@ function getVP09CodecString(stream) {
 }
 
 /**
+ * MP4A is the same as AAC.
  * https://developer.mozilla.org/en-US/docs/Web/Media/Formats/codecs_parameter#mp4a
  * @param {ProbeStream} stream
  * @returns {string}
@@ -248,7 +264,7 @@ function getMP4ACodecString(stream) {
       frag += '.2';
       break;
     // TODO: more!
-    default: 
+    default:
       throw `Cannot handle AAC stream with profile ${stream.profile} yet. ` +
           `Please file a bug https://github.com/codedread/bitjs/issues/new`;
   }
diff --git a/package.json b/package.json
index 52e1216..106480a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@codedread/bitjs",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "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 5637e84..e4ca4b8 100644
--- a/tests/codecs.spec.js
+++ b/tests/codecs.spec.js
@@ -125,7 +125,7 @@ describe('codecs test suite', () => {
       })).to.throw();
     });
 
-    describe('AVC1', () => {
+    describe('AVC1 / H264', () => {
       /** @type {ProbeInfo} */
       let info;
 
@@ -201,6 +201,16 @@ describe('codecs test suite', () => {
               .and.satisfy(s => s.endsWith('0A"'));
         });
       });
+
+      it('Handles codec_name=h264, but no codec_tag_string', () => {
+        info.streams[0].codec_name = 'h264';
+        info.streams[0].profile = 'Main';
+        info.streams[0].codec_tag_string = '[0][0][0][0]';
+        info.streams[0].level = 20;
+        expect(getFullMIMEString(info))
+            .to.be.a('string')
+            .and.satisfy(s => s.startsWith('video/mp4; codecs="avc1.4D00'));
+      });
     });
   });
 
@@ -260,7 +270,7 @@ describe('codecs test suite', () => {
     });
   });
 
-  describe('AAC', () => {
+  describe('MP4A / AAC', () => {
     /** @type {ProbeInfo} */
     let info;
 
@@ -286,5 +296,14 @@ describe('codecs test suite', () => {
             .and.equals('audio/mp4; codecs="mp4a.40.2"');
       });
     });
+
+    it('handles codec_name=aac but no codec_tag_string', () => {
+      info.streams[0].profile = 'LC';
+      info.streams[0].codec_tag_string = '[0][0][0][0]';
+      info.streams[0].codec_name = 'aac';
+      expect(getFullMIMEString(info))
+          .to.be.a('string')
+          .and.equals('audio/mp4; codecs="mp4a.40.2"');
+    });
   });
 });