Dolby Vision fixes for Chromecast (#1844)

- Fix the link to Dolby's Dolby Vision Profiles and levels PDF
  - Was pointing to a document version that no longer exists
- Update Dolby Vision regex to match all DV codecs
  - Dolby Vision is available in 4 different (base) codecs: dvhe, dvh1, dvav, dva1
  - dvh* represents HEVC-based Dolby Vision
  - dva* represents AVC-based Dolby Vision.
- Do not remove Dolby Vision codecs on Chromecast

No need to remove Dolby Vision codecs on Chromecast. Chromecast's canDisplayType will reject them when the cast receiver or the attached display can't play Dolby Vision.

On Dolby Vision capable cast receivers attached to a TV in Dolby Vision mode, canDisplayType does not reject Dolby Vision streams. One such device is the Chromecast Ultra. With this change, Shaka Player plays Dolby Vision on qualifying setups.

Author: bartt

lib/polyfill/mediasource.js

@@ -313,8 +313,8 @@ shaka.polyfill.MediaSource.rejectCodec_ = function(codec) {
 shaka.polyfill.MediaSource.patchCastIsTypeSupported_ = function() {
   const originalIsTypeSupported = MediaSource.isTypeSupported;
 
-  // Docs from Dolby detailing profile names: https://bit.ly/2MfV72y
-  let dolbyVisionRegex = /^dv(?:he|av)\./;
+  // Docs from Dolby detailing profile names: https://bit.ly/2T2wKbu
+  let dolbyVisionRegex = /^dv(?:h[e1]|a[v1])\./;
 
   MediaSource.isTypeSupported = function(mimeType) {
     // Parse the basic MIME type from its parameters.
@@ -340,12 +340,8 @@ shaka.polyfill.MediaSource.patchCastIsTypeSupported_ = function() {
     let isDolbyVision = false;
 
     let codecList = codecs.split(',').filter(function(codec) {
-      // Remove Dolby Vision codec strings.  These are not understood on
-      // Chromecast, even though the content can still be played.
       if (dolbyVisionRegex.test(codec)) {
         isDolbyVision = true;
-        // Return false to remove this string from the list.
-        return false;
       }
 
       // We take this string as a signal for HDR, but don't remove it.