fix: VTT Cue Parsing On PlayStation 4 (#4340)

Need to exclude PlayStation 4 from TextDecoder usage, because even if TextDecoder is defined, VTT cues are not properly parsed on that platform.

Closes #4321

lib/util/string_utils.js

@@ -11,6 +11,7 @@ goog.require('shaka.log');
 goog.require('shaka.util.BufferUtils');
 goog.require('shaka.util.Error');
 goog.require('shaka.util.Lazy');
+goog.require('shaka.util.Platform');
 
 
 /**
@@ -36,7 +37,7 @@ shaka.util.StringUtils = class {
     if (uint8[0] == 0xef && uint8[1] == 0xbb && uint8[2] == 0xbf) {
       uint8 = uint8.subarray(3);
     }
-    if (window.TextDecoder) {
+    if (window.TextDecoder && !shaka.util.Platform.isPS4()) {
       // Use the TextDecoder interface to decode the text.  This has the
       // advantage compared to the previously-standard decodeUriComponent that
       // it will continue parsing even if it finds an invalid UTF8 character,
@@ -160,7 +161,7 @@ shaka.util.StringUtils = class {
    * @export
    */
   static toUTF8(str) {
-    if (window.TextEncoder) {
+    if (window.TextEncoder && !shaka.util.Platform.isPS4()) {
       const utf8Encoder = new TextEncoder();
       return shaka.util.BufferUtils.toArrayBuffer(utf8Encoder.encode(str));
     } else {