5.1 LC-AAC from DS Video (Synology) => 2.0 stereo on HDMI in (TV), why?

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Stream MKV video with 5.1 AAC lc (48 kHz) to Chromecast via DS Video 
(Synology)

What is the expected output? What do you see instead?
Expected output: 5.1 Multi-Channel output
Actual output: 2.0 stereo sound

What version of the product are you using? On what operating system?
Chromecast GA3A00032A07

Please provide any additional information below.
Can't tell whether the problem is App- or Chromecast-related as I don't have 
any other apps to stream the video to Chromecast. Playback works well, and the 
app also recognizes 5.1 AAC. I speculate that it bitstreams the audio stream as 
any transcoding with my Synology Drive usually results in fps drop to 1-2 fps 
(unwatchable), and here it doesn't. But - the output is just 2.0 stereo.

Original issue reported on code.google.com by cirk...@gmail.com on 3 Oct 2015 at 5:03

[GoogleCodeExporter]

This doesn't seem to be an issue with the Cast SDK. I recommend directing your 
questions to the Synology forum. There are many other free apps you can use to 
see if 5.1 AAC is working correctly on Chromecast. If you are able to reproduce 
the issue on other apps and are unable to find a solution on the Synology 
forum, let us know and we can consider reopening this ticket.

Original comment by jonathan...@google.com on 5 Oct 2015 at 6:32

• Changed state: NotSDK