diff --git a/externs/shaka/ads.js b/externs/shaka/ads.js
index ea8942c41..67e8a6dd9 100644
--- a/externs/shaka/ads.js
+++ b/externs/shaka/ads.js
@@ -68,7 +68,7 @@ shaka.extern.IAdManager = class extends EventTarget {
   /**
    * @param {!google.ima.dai.api.StreamRequest} imaRequest
    * @param {string=} backupUrl
-   * @return {!Promise.<!string>}
+   * @return {!Promise.<string>}
    */
   requestServerSideStream(imaRequest, backupUrl) {}
 
diff --git a/externs/shaka/text.js b/externs/shaka/text.js
index 8cd75d211..953663f13 100644
--- a/externs/shaka/text.js
+++ b/externs/shaka/text.js
@@ -128,7 +128,7 @@ shaka.extern.Cue = class {
     /**
      * The text payload of the cue.  If nestedCues is non-empty, this should be
      * empty.  Top-level block containers should have no payload of their own.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.payload;
@@ -234,14 +234,14 @@ shaka.extern.Cue = class {
 
     /**
      * Text color as a CSS color, e.g. "#FFFFFF" or "white".
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.color;
 
     /**
      * Text background color as a CSS color, e.g. "#FFFFFF" or "white".
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.backgroundColor;
@@ -257,14 +257,14 @@ shaka.extern.Cue = class {
 
     /**
      * The URL of the background image, e.g. "data:[mime type];base64,[data]".
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.backgroundImage;
 
     /**
      * The border around this cue as a CSS border.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.border;
@@ -292,28 +292,28 @@ shaka.extern.Cue = class {
 
     /**
      * Text font family.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.fontFamily;
 
     /**
      * Text letter spacing as a CSS letter-spacing value.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.letterSpacing;
 
     /**
      * Text line padding as a CSS line-padding value.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.linePadding;
 
     /**
      * Opacity of the cue element, from 0-1.
-     * @type {!number}
+     * @type {number}
      * @exportDoc
      */
     this.opacity;
@@ -335,7 +335,7 @@ shaka.extern.Cue = class {
 
     /**
      * Id of the cue.
-     * @type {!string}
+     * @type {string}
      * @exportDoc
      */
     this.id;
diff --git a/lib/cea/cea608_data_channel.js b/lib/cea/cea608_data_channel.js
index 4a25063b7..6c08b5d76 100644
--- a/lib/cea/cea608_data_channel.js
+++ b/lib/cea/cea608_data_channel.js
@@ -17,8 +17,8 @@ goog.requireType('shaka.cea.ICaptionDecoder');
  */
 shaka.cea.Cea608DataChannel = class {
   /**
-   * @param {!number} fieldNum Field number.
-   * @param {!number} channelNum Channel number.
+   * @param {number} fieldNum Field number.
+   * @param {number} channelNum Channel number.
    */
   constructor(fieldNum, channelNum) {
     /**
@@ -58,7 +58,7 @@ shaka.cea.Cea608DataChannel = class {
 
     /**
      * End time of the previous caption, serves as start time of next caption.
-     * @private {!number}
+     * @private {number}
      */
     this.prevEndTime_ = 0;
 
@@ -83,9 +83,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Gets the row index from a Preamble Address Code byte pair.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!number} Row index.
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {number} Row index.
    * @private
    */
   pacToRow_(b1, b2) {
@@ -106,8 +106,8 @@ shaka.cea.Cea608DataChannel = class {
    * PAC - Preamble Address Code.
    * b1 is of the form |P|0|0|1|C|0|ROW|
    * b2 is of the form |P|1|N|ATTRIBUTE|U|
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
    * @private
    */
   controlPac_(b1, b2) {
@@ -165,7 +165,7 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Mid-Row control code handler.
-   * @param {!number} b2 Byte #2.
+   * @param {number} b2 Byte #2.
    * @private
    */
   controlMidrow_(b2) {
@@ -198,8 +198,8 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Background attribute control code handler.
-   * @param {!number} b1 Byte #1
-   * @param {!number} b2 Byte #2.
+   * @param {number} b1 Byte #1
+   * @param {number} b2 Byte #2.
    * @private
    */
   controlBackgroundAttribute_(b1, b2) {
@@ -279,7 +279,7 @@ shaka.cea.Cea608DataChannel = class {
    * CR only affects scroll windows (Rollup and Text modes).
    * Any currently buffered line needs to be emitted, along
    * with a window scroll action.
-   * @param {!number} pts in seconds.
+   * @param {number} pts in seconds.
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -311,8 +311,8 @@ shaka.cea.Cea608DataChannel = class {
    * Handles RU2, RU3, RU4 - Roll-Up, N rows.
    * If in TEXT, POPON or PAINTON, any displayed captions are erased.
    *    This means must force emit entire display buffer.
-   * @param {!number} scrollSize New scroll window size.
-   * @param {!number} pts
+   * @param {number} scrollSize New scroll window size.
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -356,7 +356,7 @@ shaka.cea.Cea608DataChannel = class {
    * Handles EDM - Erase Displayed Mem
    * Mode check:
    * EDM affects all captioning modes (but not Text mode);
-   * @param {!number} pts
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -375,7 +375,7 @@ shaka.cea.Cea608DataChannel = class {
   /**
    * Handles RDC - Resume Direct Captions. Initiates Paint-On captioning mode.
    * RDC does not affect current display, so nothing needs to be forced out yet.
-   * @param {!number} pts in seconds
+   * @param {number} pts in seconds
    * @private
    */
   controlRdc_(pts) {
@@ -403,7 +403,7 @@ shaka.cea.Cea608DataChannel = class {
    * Handles EOC - End Of Caption (flip mem)
    * This forces Pop-On mode, and swaps the displayed and nondisplayed memories.
    * @private
-   * @param {!number} pts
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    */
   controlEoc_(pts) {
@@ -472,8 +472,8 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Handles a Basic North American byte pair.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
    */
   handleBasicNorthAmericanChar(b1, b2) {
     this.curbuf_.addChar(
@@ -484,8 +484,8 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Handles an Extended Western European byte pair.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
    * @private
    */
   handleExtendedWesternEuropeanChar_(b1, b2) {
@@ -539,9 +539,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if this is a Miscellaneous control code.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isMiscellaneous_(b1, b2) {
@@ -553,9 +553,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if this is a PAC control code.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isPAC_(b1, b2) {
@@ -567,9 +567,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if this is a Midrow style change control code.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isMidrowStyleChange_(b1, b2) {
@@ -581,9 +581,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if this is a background attribute control code.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isBackgroundAttribute_(b1, b2) {
@@ -596,9 +596,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if the character is in the Special North American char. set.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isSpecialNorthAmericanChar_(b1, b2) {
@@ -610,9 +610,9 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if the character is in the Extended Western European char. set.
-   * @param {!number} b1 Byte 1.
-   * @param {!number} b2 Byte 2.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @param {number} b2 Byte 2.
+   * @return {boolean}
    * @private
    */
   isExtendedWesternEuropeanChar_(b1, b2) {
@@ -624,8 +624,8 @@ shaka.cea.Cea608DataChannel = class {
 
   /**
    * Checks if the data contains a control code.
-   * @param {!number} b1 Byte 1.
-   * @return {!boolean}
+   * @param {number} b1 Byte 1.
+   * @return {boolean}
    */
   static isControlCode(b1) {
     // For control codes, the first byte takes the following form:
@@ -636,7 +636,7 @@ shaka.cea.Cea608DataChannel = class {
 
 /**
  * Command codes.
- * @enum {!number}
+ * @enum {number}
  * @private
  */
 shaka.cea.Cea608DataChannel.MiscCmd_ = {
@@ -691,7 +691,7 @@ shaka.cea.Cea608DataChannel.MiscCmd_ = {
 
 /**
  * Caption type.
- * @private @const @enum {!number}
+ * @private @const @enum {number}
  */
 shaka.cea.Cea608DataChannel.CaptionType = {
   NONE: 0,
@@ -702,7 +702,7 @@ shaka.cea.Cea608DataChannel.CaptionType = {
 };
 
 /**
- * @const {!Array<!string>}
+ * @const {!Array<string>}
  */
 shaka.cea.Cea608DataChannel.BG_COLORS = [
   'black',
@@ -716,7 +716,7 @@ shaka.cea.Cea608DataChannel.BG_COLORS = [
 ];
 
 /**
- * @const {!Array<!string>}
+ * @const {!Array<string>}
  */
 shaka.cea.Cea608DataChannel.TEXT_COLORS = [
   'white',
@@ -743,20 +743,20 @@ shaka.cea.Cea608DataChannel.Style;
 /**
  * CEA closed captions packet.
  * @typedef {{
-  *   pts: !number,
-  *   type: !number,
-  *   ccData1: !number,
-  *   ccData2: !number,
-  *   order: !number
+  *   pts: number,
+  *   type: number,
+  *   ccData1: number,
+  *   ccData2: number,
+  *   order: number
   * }}
   *
-  * @property {!number} pts
+  * @property {number} pts
   *   Presentation timestamp (in second) at which this packet was received.
-  * @property {!number} type
+  * @property {number} type
   *   Type of the packet. Either 0 or 1, representing the CEA-608 field.
-  * @property {!number} ccData1 CEA-608 byte 1.
-  * @property {!number} ccData2 CEA-608 byte 2.
-  * @property {(!number)} order
+  * @property {number} ccData1 CEA-608 byte 1.
+  * @property {number} ccData2 CEA-608 byte 2.
+  * @property {number} order
   *   A number indicating the order this packet was received in a sequence
   *   of packets. Used to break ties in a stable sorting algorithm
   */
diff --git a/lib/cea/cea608_memory.js b/lib/cea/cea608_memory.js
index de1f15828..a30d8e807 100644
--- a/lib/cea/cea608_memory.js
+++ b/lib/cea/cea608_memory.js
@@ -16,8 +16,8 @@ goog.requireType('shaka.cea.ICaptionDecoder');
  */
 shaka.cea.Cea608Memory = class {
   /**
-   * @param {!number} fieldNum Field number.
-   * @param {!number} channelNum Channel number.
+   * @param {number} fieldNum Field number.
+   * @param {number} channelNum Channel number.
    */
   constructor(fieldNum, channelNum) {
     /**
@@ -28,45 +28,45 @@ shaka.cea.Cea608Memory = class {
 
     /**
      * Current row.
-     * @private {!number}
+     * @private {number}
      */
     this.row_ = 1;
 
     /**
      * Number of rows in the scroll window. Used for rollup mode.
-     * @private {!number}
+     * @private {number}
      */
     this.scrollRows_ = 0;
 
     /**
      * Field number.
-     * @private {!number}
+     * @private {number}
      */
     this.fieldNum_ = fieldNum;
 
     /**
      * Channel number.
-     * @private {!number}
+     * @private {number}
      */
     this.channelNum_ = channelNum;
 
     /**
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.underline_ = false;
 
     /**
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.italics_ = false;
 
     /**
-     * @private {!string}
+     * @private {string}
      */
     this.textColor_ = shaka.cea.CeaUtils.DEFAULT_TXT_COLOR;
 
     /**
-     * @private {!string}
+     * @private {string}
      */
     this.backgroundColor_ = shaka.cea.CeaUtils.DEFAULT_BG_COLOR;
 
@@ -75,8 +75,8 @@ shaka.cea.Cea608Memory = class {
 
   /**
    * Emits a closed caption based on the state of the buffer.
-   * @param {!number} startTime Start time of the cue.
-   * @param {!number} endTime End time of the cue.
+   * @param {number} startTime Start time of the cue.
+   * @param {number} endTime End time of the cue.
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    */
   forceEmit(startTime, endTime) {
@@ -96,28 +96,28 @@ shaka.cea.Cea608Memory = class {
   }
 
   /**
-   * @return {!number}
+   * @return {number}
    */
   getRow() {
     return this.row_;
   }
 
   /**
-   * @param {!number} row
+   * @param {number} row
    */
   setRow(row) {
     this.row_ = row;
   }
 
   /**
-   * @return {!number}
+   * @return {number}
    */
   getScrollSize() {
     return this.scrollRows_;
   }
 
   /**
-   * @param {!number} scrollRows
+   * @param {number} scrollRows
    */
   setScrollSize(scrollRows) {
     this.scrollRows_ = scrollRows;
@@ -126,7 +126,7 @@ shaka.cea.Cea608Memory = class {
   /**
    * Adds a character to the buffer.
    * @param {!shaka.cea.Cea608Memory.CharSet} set Character set.
-   * @param {!number} b CC byte to add.
+   * @param {number} b CC byte to add.
    */
   addChar(set, b) {
     // Valid chars are in the range [0x20, 0x7f]
@@ -179,9 +179,9 @@ shaka.cea.Cea608Memory = class {
 
   /**
    * Moves rows of characters.
-   * @param {!number} dst Destination row index.
-   * @param {!number} src Source row index.
-   * @param {!number} count Count of rows to move.
+   * @param {number} dst Destination row index.
+   * @param {number} src Source row index.
+   * @param {number} count Count of rows to move.
    */
   moveRows(dst, src, count) {
     if (dst >= src) {
@@ -197,8 +197,8 @@ shaka.cea.Cea608Memory = class {
 
   /**
    * Resets rows of characters.
-   * @param {!number} idx Starting index.
-   * @param {!number} count Count of rows to reset.
+   * @param {number} idx Starting index.
+   * @param {number} count Count of rows to reset.
    */
   resetRows(idx, count) {
     for (let i = 0; i <= count; i++) {
@@ -223,28 +223,28 @@ shaka.cea.Cea608Memory = class {
   }
 
   /**
-   * @param {!boolean} underline
+   * @param {boolean} underline
    */
   setUnderline(underline) {
     this.underline_ = underline;
   }
 
   /**
-   * @param {!boolean} italics
+   * @param {boolean} italics
    */
   setItalics(italics) {
     this.italics_ = italics;
   }
 
   /**
-   * @param {!string} color
+   * @param {string} color
    */
   setTextColor(color) {
     this.textColor_ = color;
   }
 
   /**
-   * @param {!string} color
+   * @param {string} color
    */
   setBackgroundColor(color) {
     this.backgroundColor_ = color;
@@ -253,13 +253,13 @@ shaka.cea.Cea608Memory = class {
 
 /**
  * Maximum number of rows in the buffer.
- * @const {!number}
+ * @const {number}
  */
 shaka.cea.Cea608Memory.CC_ROWS = 15;
 
 /**
  * Characters sets.
- * @const @enum {!number}
+ * @const @enum {number}
  */
 shaka.cea.Cea608Memory.CharSet = {
   BASIC_NORTH_AMERICAN: 0,
@@ -270,7 +270,7 @@ shaka.cea.Cea608Memory.CharSet = {
 
 /**
  * Basic North American char set deviates from ASCII with these exceptions.
- * @private @const {!Map<!number, !string>}
+ * @private @const {!Map<number, string>}
  */
 shaka.cea.Cea608Memory.CharSet.BasicNorthAmericanChars = new Map([
   [0x27, '’'], [0x2a, 'á'], [0x5c, 'é'], [0x5c, 'é'], [0x5e, 'í'], [0x5f, 'ó'],
@@ -280,7 +280,7 @@ shaka.cea.Cea608Memory.CharSet.BasicNorthAmericanChars = new Map([
 /**
  * Special North American char set.
  * Note: Transparent Space is currently implemented as a regular space.
- * @private @const {!Map<!number, !string>}
+ * @private @const {!Map<number, string>}
  */
 shaka.cea.Cea608Memory.CharSet.SpecialNorthAmericanChars = new Map([
   [0x30, '®'], [0x31, '°'], [0x32, '½'], [0x33, '¿'], [0x34, '™'], [0x35, '¢'],
@@ -290,7 +290,7 @@ shaka.cea.Cea608Memory.CharSet.SpecialNorthAmericanChars = new Map([
 
 /**
  * Extended Spanish/Misc/French char set.
- * @private @const {!Map<!number, !string>}
+ * @private @const {!Map<number, string>}
  */
 shaka.cea.Cea608Memory.CharSet.ExtendedSpanishFrench = new Map([
   [0x20, 'Á'], [0x21, 'É'], [0x22, 'Ó'], [0x23, 'Ú'], [0x24, 'Ü'], [0x25, 'ü'],
@@ -303,7 +303,7 @@ shaka.cea.Cea608Memory.CharSet.ExtendedSpanishFrench = new Map([
 
 /**
  * Extended Portuguese/German/Danish char set.
- * @private @const {!Map<!number, !string>}
+ * @private @const {!Map<number, string>}
  */
 shaka.cea.Cea608Memory.CharSet.ExtendedPortugueseGerman = new Map([
   [0x20, 'Ã'], [0x21, 'ã'], [0x22, 'Í'], [0x23, 'Ì'], [0x24, 'ì'], [0x25, 'Ò'],
diff --git a/lib/cea/cea708_service.js b/lib/cea/cea708_service.js
index 179ba8a84..39d7800a8 100644
--- a/lib/cea/cea708_service.js
+++ b/lib/cea/cea708_service.js
@@ -18,12 +18,12 @@ goog.require('shaka.util.Error');
  */
 shaka.cea.Cea708Service = class {
   /**
-   * @param {!number} serviceNumber
+   * @param {number} serviceNumber
    */
   constructor(serviceNumber) {
     /**
      * Number for this specific service (1 - 63).
-     * @private {!number}
+     * @private {number}
      */
     this.serviceNumber_ = serviceNumber;
 
@@ -84,7 +84,7 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Handles G0 group data.
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleG0_(controlCode) {
@@ -102,7 +102,7 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Handles G1 group data.
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleG1_(controlCode) {
@@ -115,7 +115,7 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Handles G2 group data.
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleG2_(controlCode) {
@@ -134,7 +134,7 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Handles G3 group data.
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleG3_(controlCode) {
@@ -155,8 +155,8 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Handles C0 group data.
-   * @param {!number} controlCode
-   * @param {!number} pts
+   * @param {number} controlCode
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -206,8 +206,8 @@ shaka.cea.Cea708Service = class {
    * Processes C1 group data.
    * These are caption commands.
    * @param {!shaka.cea.DtvccPacket} dtvccPacket
-   * @param {!number} captionCommand
-   * @param {!number} pts in seconds
+   * @param {number} captionCommand
+   * @param {number} pts in seconds
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @throws {!shaka.util.Error} a possible out-of-range buffer read.
    * @private
@@ -255,7 +255,7 @@ shaka.cea.Cea708Service = class {
   /**
    * Handles C2 group data.
    * @param {!shaka.cea.DtvccPacket} dtvccPacket
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleC2_(dtvccPacket, controlCode) {
@@ -273,7 +273,7 @@ shaka.cea.Cea708Service = class {
   /**
    * Handles C3 group data.
    * @param {!shaka.cea.DtvccPacket} dtvccPacket
-   * @param {!number} controlCode
+   * @param {number} controlCode
    * @private
    */
   handleC3_(dtvccPacket, controlCode) {
@@ -287,7 +287,7 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowNum
+   * @param {number} windowNum
    * @private
    */
   setCurrentWindow_(windowNum) {
@@ -300,8 +300,8 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Yields each non-null window specified in the 8-bit bitmap.
-   * @param {!number} bitmap 8 bits corresponding to each of the 8 windows.
-   * @return {!Iterable.<!number>}
+   * @param {number} bitmap 8 bits corresponding to each of the 8 windows.
+   * @return {!Iterable.<number>}
    * @private
    */
   * getSpecifiedWindowIds_(bitmap) {
@@ -315,8 +315,8 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowsBitmap
-   * @param {!number} pts
+   * @param {number} windowsBitmap
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -336,8 +336,8 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowsBitmap
-   * @param {!number} pts
+   * @param {number} windowsBitmap
+   * @param {number} pts
    * @private
    */
   displayWindows_(windowsBitmap, pts) {
@@ -353,8 +353,8 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowsBitmap
-   * @param {!number} pts
+   * @param {number} windowsBitmap
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -374,8 +374,8 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowsBitmap
-   * @param {!number} pts
+   * @param {number} windowsBitmap
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -399,8 +399,8 @@ shaka.cea.Cea708Service = class {
   }
 
   /**
-   * @param {!number} windowsBitmap
-   * @param {!number} pts
+   * @param {number} windowsBitmap
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -422,7 +422,7 @@ shaka.cea.Cea708Service = class {
   /**
    * Emits anything currently present in any of the windows, and then
    * deletes all windows, cancels all delays, reinitializes the service.
-   * @param {!number} pts
+   * @param {number} pts
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    * @private
    */
@@ -559,8 +559,8 @@ shaka.cea.Cea708Service = class {
 
   /**
    * @param {!shaka.cea.DtvccPacket} dtvccPacket
-   * @param {!number} windowNum
-   * @param {!number} pts
+   * @param {number} windowNum
+   * @param {number} pts
    * @throws {!shaka.util.Error}
    * @private
    */
@@ -612,10 +612,10 @@ shaka.cea.Cea708Service = class {
 
   /**
    * Maps 64 possible CEA-708 colors to 8 CSS colors.
-   * @param {!number} red value from 0-3
-   * @param {!number} green value from 0-3
-   * @param {!number} blue value from 0-3
-   * @return {!string}
+   * @param {number} red value from 0-3
+   * @param {number} green value from 0-3
+   * @param {number} blue value from 0-3
+   * @return {string}
    * @private
    */
   rgbColorToHex_(red, green, blue) {
@@ -636,34 +636,34 @@ shaka.cea.Cea708Service = class {
 };
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Service.ASCII_BACKSPACE = 0x08;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Service.ASCII_FORM_FEED = 0x0c;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Service.ASCII_CARRIAGE_RETURN = 0x0d;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Service.ASCII_HOR_CARRIAGE_RETURN = 0x0e;
 
 /**
  * For extended control codes in block_data on CEA-708, byte 1 is 0x10.
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Service.EXT_CEA708_CTRL_CODE_BYTE1 = 0x10;
 
 /**
  * Holds characters mapping for bytes that are G2 control codes.
- * @private @const {!Map<!number, !string>}
+ * @private @const {!Map<number, string>}
  */
 shaka.cea.Cea708Service.G2Charset = new Map([
   [0x20, ' '], [0x21, '\xa0'], [0x25, '…'], [0x2a, 'Š'], [0x2c, 'Œ'],
@@ -675,7 +675,7 @@ shaka.cea.Cea708Service.G2Charset = new Map([
 
 /**
  * An array of 8 colors that 64 colors can be quantized to. Order here matters.
- * @private @const {!Array<!string>}
+ * @private @const {!Array<string>}
  */
 shaka.cea.Cea708Service.Colors = [
   'black', 'blue', 'green', 'cyan',
@@ -691,12 +691,12 @@ shaka.cea.Cea708Service.Colors = [
  *   order: number
  * }}
  *
- * @property {!number} pts
+ * @property {number} pts
  *   Presentation timestamp (in second) at which this packet was received.
- * @property {!number} type
+ * @property {number} type
  *   Type of the byte. Either 2 or 3, DTVCC Packet Data or a DTVCC Packet Start.
- * @property {!number} value The byte containing data relevant to the packet.
- * @property {!number} order
+ * @property {number} value The byte containing data relevant to the packet.
+ * @property {number} order
  *   A number indicating the order this packet was received in a sequence
  *   of packets. Used to break ties in a stable sorting algorithm
  */
diff --git a/lib/cea/cea708_window.js b/lib/cea/cea708_window.js
index 15df5e4ef..efaf024ac 100644
--- a/lib/cea/cea708_window.js
+++ b/lib/cea/cea708_window.js
@@ -18,38 +18,38 @@ goog.require('shaka.util.Functional');
  */
 shaka.cea.Cea708Window = class {
   /**
-   * @param {!number} windowNum
+   * @param {number} windowNum
    */
   constructor(windowNum) {
     /**
      * A number from 0 - 7 indicating the window number in the
      * service that owns this window.
-     * @private {!number}
+     * @private {number}
      */
     this.windowNum_ = windowNum;
 
     /**
      * Indicates whether this window is visible.
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.visible_ = false;
 
     /**
      * Indicates whether the horizontal and vertical anchors coordinates specify
      * a percentage of the screen, or physical coordinates on the screen.
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.relativeToggle_ = false;
 
     /**
      * Horizontal anchor. Loosely corresponds to a WebVTT viewport X anchor.
-     * @private {!number}
+     * @private {number}
      */
     this.horizontalAnchor_ = 0;
 
     /**
      * Vertical anchor. Loosely corresponds to a WebVTT viewport Y anchor.
-     * @private {!number}
+     * @private {number}
      */
     this.verticalAnchor_ = 0;
 
@@ -62,19 +62,19 @@ shaka.cea.Cea708Window = class {
      * 6________7________8
      * Diagram is valid as per CEA-708-E section 8.4.4.
      * Each of these locations corresponds to a WebVTT region's "region anchor".
-     * @private {!number}
+     * @private {number}
      */
     this.anchorId_ = 0;
 
     /**
      * Indicates the number of rows in this window's buffer/memory.
-     * @private {!number}
+     * @private {number}
      */
     this.rowCount_ = 0;
 
     /**
      * Indicates the number of columns in this window's buffer/memory.
-     * @private {!number}
+     * @private {number}
      */
     this.colCount_ = 0;
 
@@ -92,43 +92,43 @@ shaka.cea.Cea708Window = class {
     this.memory_ = [];
 
     /**
-     * @private {!number}
+     * @private {number}
      */
     this.startTime_ = 0;
 
     /**
      * Row that the current pen is pointing at.
-     * @private {!number}
+     * @private {number}
      */
     this.row_ = 0;
 
     /**
      * Column that the current pen is pointing at.
-     * @private {!number}
+     * @private {number}
      */
     this.col_ = 0;
 
     /**
      * Indicates whether the current pen position is italicized.
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.italics_ = false;
 
     /**
      * Indicates whether the current pen position is underlined.
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.underline_ = false;
 
     /**
      * Indicates the text color at the current pen position.
-     * @private {!string}
+     * @private {string}
      */
     this.textColor_ = shaka.cea.CeaUtils.DEFAULT_TXT_COLOR;
 
     /**
      * Indicates the background color at the current pen position.
-     * @private {!string}
+     * @private {string}
      */
     this.backgroundColor_ = shaka.cea.CeaUtils.DEFAULT_BG_COLOR;
 
@@ -141,13 +141,13 @@ shaka.cea.Cea708Window = class {
   }
 
   /**
-   * @param {!boolean} visible
-   * @param {!number} verticalAnchor
-   * @param {!number} horizontalAnchor
-   * @param {!number} anchorId
-   * @param {!boolean} relativeToggle
-   * @param {!number} rowCount
-   * @param {!number} colCount
+   * @param {boolean} visible
+   * @param {number} verticalAnchor
+   * @param {number} horizontalAnchor
+   * @param {number} anchorId
+   * @param {boolean} relativeToggle
+   * @param {number} rowCount
+   * @param {number} colCount
    */
   defineWindow(visible, verticalAnchor, horizontalAnchor, anchorId,
       relativeToggle, rowCount, colCount) {
@@ -185,7 +185,7 @@ shaka.cea.Cea708Window = class {
 
   /**
    * Sets the unicode value for a char at the current pen location.
-   * @param {!string} char
+   * @param {string} char
    */
   setCharacter(char) {
     // Check if the pen is out of bounds.
@@ -238,7 +238,7 @@ shaka.cea.Cea708Window = class {
   }
 
   /**
-   * @return {!boolean}
+   * @return {boolean}
    */
   isVisible() {
     return this.visible_;
@@ -246,7 +246,7 @@ shaka.cea.Cea708Window = class {
 
   /**
    * Moves up <count> rows in the buffer.
-   * @param {!number} count
+   * @param {number} count
    * @private
    */
   moveUpRows_(count) {
@@ -286,8 +286,8 @@ shaka.cea.Cea708Window = class {
   }
 
   /**
-   * @param {!number} endTime
-   * @param {!number} serviceNumber Number of the service emitting this caption.
+   * @param {number} endTime
+   * @param {number} serviceNumber Number of the service emitting this caption.
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    */
   forceEmit(endTime, serviceNumber) {
@@ -318,8 +318,8 @@ shaka.cea.Cea708Window = class {
   }
 
   /**
-   * @param {!number} row
-   * @param {!number} col
+   * @param {number} row
+   * @param {number} col
    */
   setPenLocation(row, col) {
     this.row_ = row;
@@ -327,28 +327,28 @@ shaka.cea.Cea708Window = class {
   }
 
   /**
-   * @param {!string} backgroundColor
+   * @param {string} backgroundColor
    */
   setPenBackgroundColor(backgroundColor) {
     this.backgroundColor_ = backgroundColor;
   }
 
   /**
-   * @param {!string} textColor
+   * @param {string} textColor
    */
   setPenTextColor(textColor) {
     this.textColor_ = textColor;
   }
 
   /**
-   * @param {!boolean} underline
+   * @param {boolean} underline
    */
   setPenUnderline(underline) {
     this.underline_ = underline;
   }
 
   /**
-   * @param {!boolean} italics
+   * @param {boolean} italics
    */
   setPenItalics(italics) {
     this.italics_ = italics;
@@ -394,7 +394,7 @@ shaka.cea.Cea708Window = class {
 
   /**
    * Sets the start time for the cue to be emitted.
-   * @param {!number} pts
+   * @param {number} pts
    */
   setStartTime(pts) {
     this.startTime_ = pts;
@@ -403,7 +403,7 @@ shaka.cea.Cea708Window = class {
 
 /**
  * Caption type.
- * @const @enum {!number}
+ * @const @enum {number}
  */
 shaka.cea.Cea708Window.TextJustification = {
   LEFT: 0,
@@ -415,12 +415,12 @@ shaka.cea.Cea708Window.TextJustification = {
 /**
  * Can be indexed 0-31 for 4:3 format, and 0-41 for 16:9 formats.
  * Thus the absolute maximum is 42 columns for the 16:9 format.
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Window.MAX_COLS = 42;
 
 /**
  * Maximum of 15 rows that can be indexed from 0 to 14.
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.Cea708Window.MAX_ROWS = 15;
diff --git a/lib/cea/cea_decoder.js b/lib/cea/cea_decoder.js
index e5e70a073..dbf355270 100644
--- a/lib/cea/cea_decoder.js
+++ b/lib/cea/cea_decoder.js
@@ -43,13 +43,13 @@ shaka.cea.CeaDecoder = class {
 
     /**
      * Number of consecutive bad frames decoded on CEA-608.
-     * @private {!number}
+     * @private {number}
      */
     this.badFrames_ = 0;
 
     /**
      * A map containing the stream for each mode.
-     * @private {!Map<!string, !shaka.cea.Cea608DataChannel>}
+     * @private {!Map<string, !shaka.cea.Cea608DataChannel>}
      */
     this.cea608ModeToStream_ = new Map([
       ['CC1', new shaka.cea.Cea608DataChannel(0, 0)], // F1 + C1 -> CC1
@@ -60,20 +60,20 @@ shaka.cea.CeaDecoder = class {
 
     /**
      * The current channel that is active on CEA-608 field 1.
-     * @private {!number}
+     * @private {number}
      */
     this.currentField1Channel_ = 0;
 
     /**
      * The current channel that is active on CEA-608 field 2.
-     * @private {!number}
+     * @private {number}
      */
     this.currentField2Channel_ = 0;
 
     /**
      * Map of service number to CEA-708 services, initially empty. Since there
      * can be up to 63 services, they are created dynamically only when needed.
-     * @private {!Map<!number, shaka.cea.Cea708Service>}
+     * @private {!Map<number, shaka.cea.Cea708Service>}
      */
     this.serviceNumberToService_ = new Map();
 
@@ -360,8 +360,8 @@ shaka.cea.CeaDecoder = class {
 
   /**
    * Checks if a byte has odd parity (Odd number of 1s in binary).
-   * @param {!number} byte
-   * @return {!boolean} True if the byte has odd parity.
+   * @param {number} byte
+   * @return {boolean} True if the byte has odd parity.
    * @private
    */
   isOddParity_(byte) {
@@ -376,29 +376,29 @@ shaka.cea.CeaDecoder = class {
 
 /**
  * itu_t_35_provider_code for ATSC user_data
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.ATSC_PROVIDER_CODE = 0x0031;
 
 /**
  * When provider is ATSC user data, the ATSC_user_identifier code
  * for ATSC1_data is "GA94" (0x47413934)
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.ATSC1_USER_IDENTIFIER = 0x47413934;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.NTSC_CC_FIELD_1 = 0;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.NTSC_CC_FIELD_2 = 1;
 
 /**
  * 0xB5 is USA's code (Rec. ITU-T T.35)
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.USA_COUNTRY_CODE = 0xb5;
diff --git a/lib/cea/cea_utils.js b/lib/cea/cea_utils.js
index 63802e080..f9075699d 100644
--- a/lib/cea/cea_utils.js
+++ b/lib/cea/cea_utils.js
@@ -15,10 +15,10 @@ shaka.cea.CeaUtils = class {
   /**
    * Emits a closed caption based on the state of the buffer.
    * @param {!shaka.text.Cue} topLevelCue
-   * @param {!string} stream
+   * @param {string} stream
    * @param {!Array<!Array<?shaka.cea.CeaUtils.StyledChar>>} memory
-   * @param {!number} startTime Start time of the cue.
-   * @param {!number} endTime End time of the cue.
+   * @param {number} startTime Start time of the cue.
+   * @param {number} endTime End time of the cue.
    * @return {?shaka.cea.ICaptionDecoder.ClosedCaption}
    */
   static getParsedCaption(topLevelCue, stream, memory, startTime, endTime) {
@@ -153,12 +153,12 @@ shaka.cea.CeaUtils = class {
   }
 
   /**
-   * @param {!number} startTime
-   * @param {!number} endTime
-   * @param {!boolean} underline
-   * @param {!boolean} italics
-   * @param {!string} txtColor
-   * @param {!string} bgColor
+   * @param {number} startTime
+   * @param {number} endTime
+   * @param {boolean} underline
+   * @param {boolean} italics
+   * @param {string} txtColor
+   * @param {string} bgColor
    * @return {!shaka.text.Cue}
    */
   static createStyledCue(startTime, endTime, underline,
@@ -176,8 +176,8 @@ shaka.cea.CeaUtils = class {
   }
 
   /**
-   * @param {!number} startTime
-   * @param {!number} endTime
+   * @param {number} startTime
+   * @param {number} endTime
    * @return {!shaka.text.Cue}
    */
   static createLineBreakCue(startTime, endTime) {
@@ -198,61 +198,61 @@ shaka.cea.CeaUtils.StyledChar = class {
    */
   constructor(character, underline, italics, backgroundColor, textColor) {
     /**
-     * @private {!string}
+     * @private {string}
      */
     this.character_ = character;
 
     /**
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.underline_ = underline;
 
     /**
-     * @private {!boolean}
+     * @private {boolean}
      */
     this.italics_ = italics;
 
     /**
-     * @private {!string}
+     * @private {string}
      */
     this.backgroundColor_ = backgroundColor;
 
     /**
-     * @private {!string}
+     * @private {string}
      */
     this.textColor_ = textColor;
   }
 
   /**
-   * @return {!string}
+   * @return {string}
    */
   getChar() {
     return this.character_;
   }
 
   /**
-   * @return {!boolean}
+   * @return {boolean}
    */
   isUnderlined() {
     return this.underline_;
   }
 
   /**
-   * @return {!boolean}
+   * @return {boolean}
    */
   isItalicized() {
     return this.italics_;
   }
 
   /**
-   * @return {!string}
+   * @return {string}
    */
   getBackgroundColor() {
     return this.backgroundColor_;
   }
 
   /**
-   * @return {!string}
+   * @return {string}
    */
   getTextColor() {
     return this.textColor_;
@@ -261,12 +261,12 @@ shaka.cea.CeaUtils.StyledChar = class {
 
 /**
  * Default background color for text.
- * @const {!string}
+ * @const {string}
  */
 shaka.cea.CeaUtils.DEFAULT_BG_COLOR = 'black';
 
 /**
  * Default text color.
- * @const {!string}
+ * @const {string}
  */
 shaka.cea.CeaUtils.DEFAULT_TXT_COLOR = 'white';
diff --git a/lib/cea/dtvcc_packet_builder.js b/lib/cea/dtvcc_packet_builder.js
index 59819391f..5078557b2 100644
--- a/lib/cea/dtvcc_packet_builder.js
+++ b/lib/cea/dtvcc_packet_builder.js
@@ -35,7 +35,7 @@ shaka.cea.DtvccPacketBuilder = class {
 
     /**
      * Keeps track of the number of bytes left to add in the current packet.
-     * @private {!number}
+     * @private {number}
      */
     this.bytesLeftToAddInCurrentPacket_ = 0;
   }
@@ -107,7 +107,7 @@ shaka.cea.DtvccPacket = class {
   constructor(packetData) {
     /**
      * Keeps track of the position to read the next byte from in the packet.
-     * @private {!number}
+     * @private {number}
      */
     this.pos_ = 0;
 
@@ -119,14 +119,14 @@ shaka.cea.DtvccPacket = class {
   }
 
   /**
-   * @return {!boolean}
+   * @return {boolean}
    */
   hasMoreData() {
     return this.pos_ < this.packetData_.length;
   }
 
   /**
-   * @return {!number}
+   * @return {number}
    */
   getPosition() {
     return this.pos_;
@@ -149,7 +149,7 @@ shaka.cea.DtvccPacket = class {
 
   /**
    * Skips the provided number of blocks in the buffer.
-   * @param {!number} numBlocks
+   * @param {number} numBlocks
    * @throws {!shaka.util.Error}
    */
   skip(numBlocks) {
@@ -164,11 +164,11 @@ shaka.cea.DtvccPacket = class {
 };
 
 /**
- * @const {!number}
+ * @const {number}
  */
 shaka.cea.DtvccPacketBuilder.DTVCC_PACKET_DATA = 2;
 
 /**
- * @const {!number}
+ * @const {number}
  */
 shaka.cea.DtvccPacketBuilder.DTVCC_PACKET_START = 3;
diff --git a/lib/cea/i_caption_decoder.js b/lib/cea/i_caption_decoder.js
index 3327e8587..8b194bfd0 100644
--- a/lib/cea/i_caption_decoder.js
+++ b/lib/cea/i_caption_decoder.js
@@ -22,7 +22,7 @@ shaka.cea.ICaptionDecoder = class {
    * @param {!Uint8Array} userDataSeiMessage
    * This is a User Data registered by Rec.ITU-T T.35 SEI message.
    * It is described in sections D.1.6 and D.2.6 of Rec. ITU-T H.264 (06/2019).
-   * @param {!number} pts PTS when this packet was received, in seconds.
+   * @param {number} pts PTS when this packet was received, in seconds.
    */
   extract(userDataSeiMessage, pts) {}
 
@@ -45,7 +45,7 @@ shaka.cea.ICaptionDecoder = class {
  * Parsed Cue.
  * @typedef {{
  *   cue: !shaka.text.Cue,
- *   stream: !string
+ *   stream: string
  * }}
  */
 shaka.cea.ICaptionDecoder.ClosedCaption;
diff --git a/lib/cea/i_cea_parser.js b/lib/cea/i_cea_parser.js
index f388441a9..acdd2e533 100644
--- a/lib/cea/i_cea_parser.js
+++ b/lib/cea/i_cea_parser.js
@@ -39,7 +39,7 @@ shaka.cea.ICeaParser.DEFAULT_TIMESCALE_VALUE = 90000;
 /**
  * @typedef {{
  *   packet: !Uint8Array,
- *   pts: !number
+ *   pts: number
  * }}
  *
  * @description Parsed Caption Packet.
@@ -47,7 +47,7 @@ shaka.cea.ICeaParser.DEFAULT_TIMESCALE_VALUE = 90000;
  * Caption packet. More specifically, it contains a "User data
  * registered by Recommendation ITU-T T.35 SEI message", from section D.1.6
  * and section D.2.6 of Rec. ITU-T H.264 (06/2019).
- * @property {!number} pts
+ * @property {number} pts
  * The presentation timestamp (pts) at which the ITU-T T.35 data shows up.
  * in seconds.
  * @exportDoc
diff --git a/lib/cea/mp4_cea_parser.js b/lib/cea/mp4_cea_parser.js
index e0d4a62a8..3b5ef80e1 100644
--- a/lib/cea/mp4_cea_parser.js
+++ b/lib/cea/mp4_cea_parser.js
@@ -36,13 +36,13 @@ shaka.cea.Mp4CeaParser = class {
 
     /**
      * Default sample duration, as specified by the TREX box.
-     * @private {!number}
+     * @private {number}
      */
     this.defaultSampleDuration_ = 0;
 
     /**
      * Default sample size, as specified by the TREX box.
-     * @private {!number}
+     * @private {number}
      */
     this.defaultSampleSize_ = 0;
   }
@@ -195,10 +195,10 @@ shaka.cea.Mp4CeaParser = class {
   /**
    * Parse MDAT box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} time
-   * @param {!number} timescale
-   * @param {!number} defaultSampleDuration
-   * @param {!number} defaultSampleSize
+   * @param {number} time
+   * @param {number} timescale
+   * @param {number} defaultSampleDuration
+   * @param {number} defaultSampleSize
    * @param {!Array<shaka.util.ParsedTRUNSample>} sampleData
    * @param {!Array<!shaka.cea.ICeaParser.CaptionPacket>} captionPackets
    * @private
diff --git a/lib/routing/walker.js b/lib/routing/walker.js
index 33dd3f425..a42528638 100644
--- a/lib/routing/walker.js
+++ b/lib/routing/walker.js
@@ -80,7 +80,7 @@ shaka.routing.Walker = class {
      * new work is added (and this is not null) it can be resolved. The only
      * time when this should be non-null is when we are waiting for more work.
      *
-     * @private {shaka.util.PublicPromise}
+     * @private {?shaka.util.PublicPromise}
      */
     this.waitForWork_ = null;
 
@@ -90,7 +90,7 @@ shaka.routing.Walker = class {
     /** @private {?shaka.routing.Walker.ActiveRoute_} */
     this.currentRoute_ = null;
 
-    /** @private {shaka.util.AbortableOperation} */
+    /** @private {?shaka.util.AbortableOperation} */
     this.currentStep_ = null;
 
     /**
diff --git a/lib/text/srt_text_parser.js b/lib/text/srt_text_parser.js
index fd99c1e90..5ca73f476 100644
--- a/lib/text/srt_text_parser.js
+++ b/lib/text/srt_text_parser.js
@@ -57,8 +57,8 @@ shaka.text.SrtTextParser = class {
   /**
    * Convert a SRT format to WebVTT
    *
-   * @param {!string} data
-   * @return {!string}
+   * @param {string} data
+   * @return {string}
    * @export
    */
   static srt2webvtt(data) {
@@ -87,8 +87,8 @@ shaka.text.SrtTextParser = class {
   /**
    * Convert a SRT cue into WebVTT cue
    *
-   * @param {!string} caption
-   * @return {!string}
+   * @param {string} caption
+   * @return {string}
    * @private
    */
   static convertSrtCue_(caption) {
diff --git a/lib/text/text_engine.js b/lib/text/text_engine.js
index 166153de9..c3e3d8f88 100644
--- a/lib/text/text_engine.js
+++ b/lib/text/text_engine.js
@@ -24,7 +24,7 @@ goog.requireType('shaka.cea.ICaptionDecoder');
 shaka.text.TextEngine = class {
   /** @param {shaka.extern.TextDisplayer} displayer */
   constructor(displayer) {
-    /** @private {shaka.extern.TextParser} */
+    /** @private {?shaka.extern.TextParser} */
     this.parser_ = null;
 
     /** @private {shaka.extern.TextDisplayer} */
diff --git a/lib/text/vtt_text_parser.js b/lib/text/vtt_text_parser.js
index 2eda51a46..b9f36c385 100644
--- a/lib/text/vtt_text_parser.js
+++ b/lib/text/vtt_text_parser.js
@@ -462,8 +462,8 @@ shaka.text.VttTextParser = class {
   }
 
   /**
-   * @param {!string} value
-   * @param {!string} defaultValue
+   * @param {string} value
+   * @param {string} defaultValue
    * @private
    */
   static getOrDefault_(value, defaultValue) {
diff --git a/lib/util/mp4_box_parsers.js b/lib/util/mp4_box_parsers.js
index bdc69ff3f..7f0b32858 100644
--- a/lib/util/mp4_box_parsers.js
+++ b/lib/util/mp4_box_parsers.js
@@ -14,7 +14,7 @@ shaka.util.Mp4BoxParsers = class {
   /**
    * Parses a TFHD Box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} flags
+   * @param {number} flags
    * @return {!shaka.util.ParsedTFHDBox}
    */
   static parseTFHD(reader, flags) {
@@ -53,7 +53,7 @@ shaka.util.Mp4BoxParsers = class {
   /**
    * Parses a TFDT Box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} version
+   * @param {number} version
    * @return {!shaka.util.ParsedTFDTBox}
    */
   static parseTFDT(reader, version) {
@@ -68,7 +68,7 @@ shaka.util.Mp4BoxParsers = class {
   /**
    * Parses a MDHD Box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} version
+   * @param {number} version
    * @return {!shaka.util.ParsedMDHDBox}
    */
   static parseMDHD(reader, version) {
@@ -107,8 +107,8 @@ shaka.util.Mp4BoxParsers = class {
   /**
    * Parses a TRUN Box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} version
-   * @param {!number} flags
+   * @param {number} version
+   * @param {number} flags
    * @return {!shaka.util.ParsedTRUNBox}
    */
   static parseTRUN(reader, version, flags) {
@@ -168,7 +168,7 @@ shaka.util.Mp4BoxParsers = class {
   /**
    * Parses a TKHD Box.
    * @param {!shaka.util.DataViewReader} reader
-   * @param {!number} version
+   * @param {number} version
    * @return {!shaka.util.ParsedTKHDBox}
    */
   static parseTKHD(reader, version) {
@@ -192,12 +192,12 @@ shaka.util.Mp4BoxParsers = class {
 
 /**
  * @typedef {{
- *    trackId: !number,
+ *    trackId: number,
  *    defaultSampleDuration: ?number,
  *    defaultSampleSize: ?number
  * }}
  *
- * @property {!number} trackId
+ * @property {number} trackId
  *   As per the spec: an integer that uniquely identifies this
  *   track over the entire life‐time of this presentation
  * @property {?number} defaultSampleDuration
@@ -213,10 +213,10 @@ shaka.util.ParsedTFHDBox;
 
 /**
  * @typedef {{
- *    baseMediaDecodeTime: !number
+ *    baseMediaDecodeTime: number
  * }}
  *
- * @property {!number} baseMediaDecodeTime
+ * @property {number} baseMediaDecodeTime
  *   As per the spec: the absolute decode time, measured on the media
  *   timeline, of the first sample in decode order in the track fragment
  *
@@ -226,10 +226,10 @@ shaka.util.ParsedTFDTBox;
 
 /**
  * @typedef {{
- *    timescale: !number
+ *    timescale: number
  * }}
  *
- * @property {!number} timescale
+ * @property {number} timescale
  *   As per the spec: an integer that specifies the time‐scale for this media;
  *   this is the number of time units that pass in one second
  *
@@ -239,13 +239,13 @@ shaka.util.ParsedMDHDBox;
 
 /**
  * @typedef {{
- *    defaultSampleDuration: !number,
- *    defaultSampleSize: !number
+ *    defaultSampleDuration: number,
+ *    defaultSampleSize: number
  * }}
  *
- * @property {!number} defaultSampleDuration
+ * @property {number} defaultSampleDuration
  *   The default sample duration to be used in track fragments
- * @property {!number} defaultSampleSize
+ * @property {number} defaultSampleSize
  *   The default sample size to be used in track fragments
  *
  * @exportDoc
@@ -254,11 +254,11 @@ shaka.util.ParsedTREXBox;
 
 /**
  * @typedef {{
- *    sampleCount: !number,
+ *    sampleCount: number,
  *    sampleData: !Array.<shaka.util.ParsedTRUNSample>
  * }}
  *
- * @property {!number} sampleCount
+ * @property {number} sampleCount
  *   As per the spec: the number of samples being added in this run;
  * @property {!Array.<shaka.util.ParsedTRUNSample>} sampleData
  *   An array of size <sampleCount> containing data for each sample
@@ -290,10 +290,10 @@ shaka.util.ParsedTRUNSample;
 
 /**
  * @typedef {{
- *    trackId: !number
+ *    trackId: number
  *  }}
  *
- * @property {!number} trackId
+ * @property {number} trackId
  *   Unique ID indicative of this track
  *
  * @exportDoc
diff --git a/test/cea/cea608_memory_unit.js b/test/cea/cea608_memory_unit.js
index f599c3d57..5cc0918d2 100644
--- a/test/cea/cea608_memory_unit.js
+++ b/test/cea/cea608_memory_unit.js
@@ -17,7 +17,7 @@ describe('Cea608Memory', () => {
   /** @type {!shaka.cea.Cea608Memory} */
   let memory;
 
-  /** @type {!string} */
+  /** @type {string} */
   const stream = 'CC1';
 
   beforeEach(() => {
diff --git a/test/cea/cea708_service_unit.js b/test/cea/cea708_service_unit.js
index 19bdc0488..71b7465e2 100644
--- a/test/cea/cea708_service_unit.js
+++ b/test/cea/cea708_service_unit.js
@@ -19,39 +19,39 @@ describe('Cea708Service', () => {
 
   /**
    * Hide window (2 bytes), with a bitmap provided to indicate all windows.
-   * @type {!Array<!number>}
+   * @type {!Array<number>}
    */
   const hideWindow = [0x8a, 0xff];
 
   /**
    * Define window (7 bytes), defines window #0 to be a visible window
    * with 32 rows and 32 columns. (We specify 31 for each since decoder adds 1).
-   * @type {!Array<!number>}
+   * @type {!Array<number>}
    */
   const defineWindow = [
     0x98, 0x38, 0x00, 0x00, 0x1f, 0x1f, 0x00,
   ];
 
-  /** @type {!number} */
+  /** @type {number} */
   const startTime = 1;
 
-  /** @type {!number} */
+  /** @type {number} */
   const endTime = 2;
 
   /**
    * We arbitrarily pick service 1 for all of these tests.
-   * @type {!number}
+   * @type {number}
    */
   const serviceNumber = 1;
 
-  /** @type {!string} */
+  /** @type {string} */
   const stream = `svc${serviceNumber}`;
 
   /**
    * Takes in a array of bytes and a presentation timestamp (in seconds),
    * and converts it into a CEA-708 DTVCC Packet.
-   * @param {!Array<!number>} bytes
-   * @param {!number} pts
+   * @param {!Array<number>} bytes
+   * @param {number} pts
    */
   const createCea708PacketFromBytes = (bytes, pts) => {
     const cea708Bytes = bytes.map((code, i) => {
diff --git a/test/cea/cea708_window_unit.js b/test/cea/cea708_window_unit.js
index 77ad6c362..7082684cb 100644
--- a/test/cea/cea708_window_unit.js
+++ b/test/cea/cea708_window_unit.js
@@ -15,22 +15,22 @@ describe('Cea708Window', () => {
   /** @type {!shaka.cea.Cea708Window} */
   let window;
 
-  /** @type {!number} */
+  /** @type {number} */
   const serviceNumber = 1; // We will arbitrarily pick service 1 for all tests.
 
-  /** @type {!string} */
+  /** @type {string} */
   const stream = `svc${serviceNumber}`;
 
-  /** @type {!number} */
+  /** @type {number} */
   const rowCount = 10;
 
-  /** @type {!number} */
+  /** @type {number} */
   const colCount = 32;
 
-  /** @type {!number} */
+  /** @type {number} */
   const startTime = 1;
 
-  /** @type {!number} */
+  /** @type {number} */
   const endTime = 2;
 
   beforeEach(() => {
diff --git a/test/cea/cea_decoder_unit.js b/test/cea/cea_decoder_unit.js
index e705130da..482dc41a0 100644
--- a/test/cea/cea_decoder_unit.js
+++ b/test/cea/cea_decoder_unit.js
@@ -13,7 +13,7 @@ goog.require('shaka.text.Cue');
 describe('CeaDecoder', () => {
   const CeaUtils = shaka.test.CeaUtils;
 
-  /** @type {!string} */
+  /** @type {string} */
   const DEFAULT_BG_COLOR = shaka.cea.CeaUtils.DEFAULT_BG_COLOR;
 
   /**
diff --git a/test/cea/dtvcc_packet_builder_unit.js b/test/cea/dtvcc_packet_builder_unit.js
index 464a01d19..39e61f237 100644
--- a/test/cea/dtvcc_packet_builder_unit.js
+++ b/test/cea/dtvcc_packet_builder_unit.js
@@ -11,10 +11,10 @@ describe('DtvccPacketBuilder', () => {
   /** @type {!shaka.cea.DtvccPacketBuilder} */
   let dtvccPacketBuilder;
 
-  /** @type {!number} */
+  /** @type {number} */
   const DTVCC_PACKET_START = shaka.cea.DtvccPacketBuilder.DTVCC_PACKET_START;
 
-  /** @type {!number} */
+  /** @type {number} */
   const DTVCC_PACKET_DATA = shaka.cea.DtvccPacketBuilder.DTVCC_PACKET_DATA;
 
   beforeEach(() => {
diff --git a/test/dash/dash_parser_manifest_unit.js b/test/dash/dash_parser_manifest_unit.js
index 371072c69..a7bc7760c 100644
--- a/test/dash/dash_parser_manifest_unit.js
+++ b/test/dash/dash_parser_manifest_unit.js
@@ -36,7 +36,7 @@ describe('DashParser Manifest', () => {
   /** @type {!ArrayBuffer} */
   let mp4Index;
 
-  /** @type {!string} */
+  /** @type {string} */
   const thumbnailScheme = 'http://dashif.org/guidelines/thumbnail_tile';
 
   beforeAll(async () => {
diff --git a/test/test/util/cea_utils.js b/test/test/util/cea_utils.js
index c8e8109c6..800f4a2ae 100644
--- a/test/test/util/cea_utils.js
+++ b/test/test/util/cea_utils.js
@@ -16,9 +16,9 @@ goog.require('shaka.text.Cue');
 shaka.test.CeaUtils = class {
   /**
    * Returns a cue with no underline/italics, and default colors
-   * @param {!number} startTime
-   * @param {!number} endTime
-   * @param {!string} payload
+   * @param {number} startTime
+   * @param {number} endTime
+   * @param {string} payload
    */
   static createDefaultCue(startTime, endTime, payload) {
     const cue = new shaka.text.Cue(startTime, endTime, payload);
@@ -29,13 +29,13 @@ shaka.test.CeaUtils = class {
 
   /**
    * Returns a cue with custom underline, italics, color, background color.
-   * @param {!number} startTime
-   * @param {!number} endTime
-   * @param {!string} payload
-   * @param {!boolean} underline
-   * @param {!boolean} italics
-   * @param {!string} textColor
-   * @param {!string} backgroundColor
+   * @param {number} startTime
+   * @param {number} endTime
+   * @param {string} payload
+   * @param {boolean} underline
+   * @param {boolean} italics
+   * @param {string} textColor
+   * @param {string} backgroundColor
    * @return {!shaka.text.Cue}
    */
   static createStyledCue(startTime, endTime, payload, underline,
@@ -54,8 +54,8 @@ shaka.test.CeaUtils = class {
 
   /**
    * Returns a cue that corresponds to a linebreak.
-   * @param {!number} startTime
-   * @param {!number} endTime
+   * @param {number} startTime
+   * @param {number} endTime
    * @return {!shaka.text.Cue}
    */
   static createLineBreakCue(startTime, endTime) {