[mythtv-users] Shield TV OpenSLES vs. AudioTrack?

[Yeechang Lee]

Jim Abernathy says:
> On the Android Mythtv wiki it suggests for the Shield TV that you should 
> use AudioTrack in the audio options instead of OpenSLES.
> 
> However, when I switch from OpenSLES to AudioTrack I get audio that 
> breaks up and goes mute. OpenSLES seems to work fine.  I'm on 
> mythtv-frontend for android v31-pre 539 with a backend that is V30.

Also on 539 on Shield, with a 29 backend.

It's the video decoder, not audio per se, that's the problem. I also
followed the Wiki Shield settings, and found that AudioTrack audio
didn't work when using timestretch with h.264 (such as what Comcast
uses on some channels). In other words, what MediaCodec handles based
on the Wiki settings; Standard decoder did not have this
problem. MediaCodec also does not handle captions in h.264.1

I use the following entries in the "Shield" playback profile:

* First: Width Range >1920, Video Formats blank, Decoder Android
  MediaCodec decoder, Max CPUs 4, Video renderer opengl, Primary
  deinterlacer Linear blend (2x, HW-GL), Fallback deinterlacer Linear
  blend (HW-GL)

* Second: Video Formats hevc, Decoder Android MediaCodec decoder, Max
  CPUs 4, Video renderer opengl, Primary deinterlacer Linear blend
  (2x, HW-GL), Fallback deinterlacer Linear blend (HW-GL)

* Third: Decoder Standard, Max CPUs 4, Video renderer opengl, Primary
  deinterlacer Linear blend (2x, HW-GL), Fallback deinterlacer Linear
  blend (HW-GL)

The idea is to have MediaCodec (Which I presume is Android's
equivalent to VDPAU/VAAPI/VDA[1]?) handle HEVC format and any format
above 1920 pixels in width, and have Standard decoder handle
everything else even if h.264/MPEG4. I got the idea from my Mac;
MythFrontend on a unibody 2012 Macbook Pro can play a 720p h.264 file
with the Standard decoder with just one CPU. VDA decoder is not
necessary and, as of 29, still has some bugs that Standard doesn't.

>My Shield TV is connected to my Samsung UHD 4K via HDMI and the TV
>sends the audio via optical cable to my AV Receiver. It's a 5.1
>speaker system and Samsung says they send out the audio from TV to AV
>Receiver in DTS format.

My receiver is not connected at the moment, so I'm using my TV's
speakers with Shield. The TV is supposed to decode DTS, but I have two
test clips that would not play their DTS tracks—complete with a
MythFrontend notification stating that audio is diabled— until I
disabled DTS from Audio | Digital Audio Capabilities. (They're HEVC,
but I don't think that has anything to do with the audio issue; the
same thing happens whether I use Standard or MediaCodec decoder.)

[1] Or XVideo for the real old-timers

-- 
Frontend:		Apple MacBook Pro 2012, Nvidia Shield 2015
Backend:		HP Microserver N40L 1.5GHz with 4x3TB HDDs
Tuners:			Three from CableCARD plus two over-the-air