Having research the problem of why Z7+ has audio issues. I will explain what is the cause.
The cause of the issue is that Formuler Z7+ has a Hi3798MV200 CPU. Instead of using google android v24 (Android N): AC3, EAC3, DTS with the new IEC API, we miss hardware / software to implement dts-hd, truehdOn Nvidia Shield: AC3, EAC3, DTS, DTS-HD, TrueHD.
The firmware uses a bespoke Himedia player to be able to player all formats. This player is limit to internal and networking media. It will not accept any stream from http and https address. The Firmware does not compily to IEC standard. Himedia have not made there code for the player open source, so no bespoke version of the different apps can use its codecs.
There are three ways the ways this can be fixed
a firmware update that complies with google android sdk.
Reverse engineer nvidia shields IEC and implement that.
Make the SDK open source.
Other Hilsilicon chip tv box make use what is call a wrapper. This allows media centre such as kodi to use the himedia player for playing local content. (Which is a lazy solution)
Now For why you cant get apps like Amazon and Netflix, in 4k.
Amazon and Netflix use DRM and there requirements for this is googles security system is call widevine. In order be able to play 4k content you must have two be certified by the streaming company and have widevine security install at level 1. The z7+ has level 3, so in order for it to play for 4k content in needs wildevine lvl 1.
How to resolve this is for a firmware update to implement wilvine lvl 1.
If formuler cant get certified by netflix but can implement lvl1, there are bespoke versions of the netfilx app available on the internet of forums like X D A.
Please Petition under thread to get these issues sorted. Otherwise people with not buy this fantastic box.
Last issue that needs to be addressed is the that we need also a way of use GLES TOOLS so we can play games thanks for reading, as this is the only tool that can be used to fix pink screen issues on games thanks.
PLEASE Leave Feedback on bottom of this thread, so these issues can gain traction, As we would like the development of the contentiously pushing the boundaries of what perfect android iptv should be.