diff --git a/lib/cea/mp4_cea_parser.js b/lib/cea/mp4_cea_parser.js
index 7d6d4ddb1ae..7ce9dab82a4 100644
--- a/lib/cea/mp4_cea_parser.js
+++ b/lib/cea/mp4_cea_parser.js
@@ -23,12 +23,7 @@ shaka.cea.Mp4CeaParser = class {
   /**
    * @param {string} mimeType
    */
-  constructor(mimeType) {
-    /**
-     * @private {string}
-     */
-    this.mimeType_ = mimeType;
-
+  constructor() {
     /**
      * SEI data processor.
      * @private
@@ -116,10 +111,6 @@ shaka.cea.Mp4CeaParser = class {
         .box('stbl', Mp4Parser.children)
         .fullBox('stsd', Mp4Parser.sampleDescription)
 
-        .box('encv', () => {
-          encrypted = true;
-        })
-
         // These are the various boxes that signal a codec.
         // Use these to set bistreamFormat_.
         .box('avc1', bitstreamFormatSetter(BitstreamFormat.H264))
@@ -130,6 +121,17 @@ shaka.cea.Mp4CeaParser = class {
         .box('dvh1', bitstreamFormatSetter(BitstreamFormat.H265))
         .box('dvhe', bitstreamFormatSetter(BitstreamFormat.H265))
 
+        .box('encv', Mp4Parser.children);
+        // These are the various boxes that signal a codec in
+        // encrypted segments
+        // Use these to set bistreamFormat_.
+        .box('avcC', bitstreamFormatSetter(BitstreamFormat.H264))
+        .box('hvcE', bitstreamFormatSetter(BitstreamFormat.H265))
+        .box('hvcC', bitstreamFormatSetter(BitstreamFormat.H265))
+        // Dobly vision is also H265.
+        .box('dvcC', bitstreamFormatSetter(BitstreamFormat.H265))
+        .box('dvvC', bitstreamFormatSetter(BitstreamFormat.H265))
+
         .parse(initSegment, /* partialOkay= */ true);
 
     // At least one track should exist, and each track should have a
@@ -142,21 +144,6 @@ shaka.cea.Mp4CeaParser = class {
           shaka.util.Error.Code.INVALID_MP4_CEA);
     }
 
-    // If the content is encrypted we have no way of knowing the
-    // bitstreamformat, so we try to get it from the mimetype.
-    if (encrypted && this.bitstreamFormat_ == BitstreamFormat.UNKNOWN) {
-      if (this.mimeType_.includes('avc1.') ||
-          this.mimeType_.includes('avc3.')) {
-        this.bitstreamFormat_ = BitstreamFormat.H264;
-      }
-      if (this.mimeType_.includes('hev1.') ||
-          this.mimeType_.includes('hvc1.') ||
-          this.mimeType_.includes('dvh1.') ||
-          this.mimeType_.includes('dvhe.')) {
-        this.bitstreamFormat_ = BitstreamFormat.H265;
-      }
-    }
-
     if (this.bitstreamFormat_ == BitstreamFormat.UNKNOWN) {
       shaka.log.alwaysWarn(
           'Unable to determine bitstream format for CEA parsing!');
diff --git a/lib/media/closed_caption_parser.js b/lib/media/closed_caption_parser.js
index 29d5cc2802a..a657bb2d923 100644
--- a/lib/media/closed_caption_parser.js
+++ b/lib/media/closed_caption_parser.js
@@ -62,7 +62,7 @@ shaka.media.ClosedCaptionParser = class {
 
     if (mimeType.toLowerCase().includes('video/mp4')) {
       // MP4 Parser to extract closed caption packets from H.264/H.265 video.
-      this.ceaParser_ = new shaka.cea.Mp4CeaParser(mimeType);
+      this.ceaParser_ = new shaka.cea.Mp4CeaParser();
     }
     if (mimeType.toLowerCase().includes('video/mp2t')) {
       // TS Parser to extract closed caption packets from H.264 video.
diff --git a/test/cea/mp4_cea_parser_unit.js b/test/cea/mp4_cea_parser_unit.js
index 282c7f7a186..3f93c65bc82 100644
--- a/test/cea/mp4_cea_parser_unit.js
+++ b/test/cea/mp4_cea_parser_unit.js
@@ -50,7 +50,7 @@ describe('Mp4CeaParser', () => {
   });
 
   it('parses cea data from mp4 stream', () => {
-    const cea708Parser = new shaka.cea.Mp4CeaParser('video/mp4');
+    const cea708Parser = new shaka.cea.Mp4CeaParser();
 
     const expectedCea708Packet = new Uint8Array([
       0xb5, 0x00, 0x31, 0x47, 0x41, 0x39, 0x34, 0x03,
@@ -71,7 +71,7 @@ describe('Mp4CeaParser', () => {
   });
 
   it('parses an invalid init segment', () => {
-    const cea708Parser = new shaka.cea.Mp4CeaParser('video/mp4');
+    const cea708Parser = new shaka.cea.Mp4CeaParser();
 
     const expected = Util.jasmineError(new shaka.util.Error(
         shaka.util.Error.Severity.CRITICAL,