MP4 support for Common Encryption 'cbcs' scheme.

media/media_options.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/features.gni")
 
 declare_args() {
   # Allows distributions to link pulseaudio directly (DT_NEEDED) instead of
   # using dlopen. This helps with automated detection of ABI mismatches and
@@ skipping 21 matching lines @@
   # Use low-memory buffers on non-Android builds of Chromecast.
   use_low_memory_buffer = is_chromecast && !is_android
 
   # Enables AC3/EAC3 audio demuxing. This is enabled only on Chromecast, since
   # it only provides demuxing, and is only useful for AC3/EAC3 audio
   # pass-through to HDMI sink on Chromecast.
   enable_ac3_eac3_audio_demuxing = proprietary_codecs && is_chromecast
 
   enable_mse_mpeg2ts_stream_parser = proprietary_codecs && is_chromecast
 
+  # Enable support for newer editions of MPEG Common Encryption (CENC)

[ddorwin, 2016/05/24 23:25:03]

This comment and variable (and define) name are inaccurate. This specifically
adds support for additional schemes. EME is by definition referencing 3rd
edition now, but only 'cenc' is currently supported in the registry. Thus, this
should be something like enable_additional_cenc_schemes. Or maybe just
enable_cbcs.

[dougsteed, 2016/05/25 17:23:21]

I see. In this name I had intended to mean 'cenc' as the abbreviation for the
"common encryption" standard, rather than the 'cenc' scheme itself. Quite
ambiguous.

+  # (ISO/IEC 23001-7).
+  # 2nd edition: was published 04/01/2015.
+  # 3rd edition: was published 02/15/2016.
+  enable_cenc_new_editions = is_chromecast
+
   # Enable HEVC/H265 demuxing. Actual decoding must be provided by the
   # platform. Enable by default for Chromecast.
   enable_hevc_demuxing = proprietary_codecs && is_chromecast
 
   # TODO(GYP): This should be a platform define.
   is_openbsd = false
 }
 
 # Use a second declare_args() to pick up possible overrides of |use_cras|.
 declare_args() {
@@ skipping 63 matching lines @@
         "cdm",
         "renderer",
       ]
       mojo_media_host = "browser"
     } else {
       mojo_media_services = [ "cdm" ]
       mojo_media_host = "utility"
     }
   }
 }