Epson EF-12 Dolby Digital / DTS output on ARC

The Epson EF-12 laser projector (Android TV) can output / passthrough 5.1 digital surround sound to your A/V home theater receiver over its HDMI2 ARC connection for both Dolby Digital AC3 and DTS movies & media using Kodi player, but with some big caveats.

First, the settings in Kodi player to output 5.1 digital surround sound to your AV Receiver over HDMI ARC:

  1. In System > Settings, turn on Expert Mode (Bottom Left Corner)
  2. In Audio section:
    1. Audio output device: AudioTrack (IEC), Kodi IEC packer (recommended)
    2. Number of channels: 2.0
    3. Output configuration: Optimized
    4. scroll down to Audio Passthrough section…
    5. Allow passthrough: ON (switch button to the right)
    6. Passthrough output device: AudioTrack (RAW), Android IEC packer
    7. Dolby Digital (AC3) capable receiver: ON
    8. – Enable Dolby Digital (AC3) transcoding: ON
    9. Dolby Digital Plus (E-AC3) capable receiver: OFF
    10. DTS capable receiver: OFF

Getting Epson EF-12 to output Digital Surround Sound

To get 5.1 digital surround sound to an AV receiver over ARC from an Epson EF-12 Android TV, the above settings were what I needed to use.

Below are the caveats & explanations of why the these settings work.

According to Kodi engineers, HDMI ARC can only output two channels of audio data. That’s why we set “Number of channels” to 2.0.

If Output configuration is not “Optimized”, only two track stereo will be passed through.

By default, the Passthrough output device is Kodi IEC packer.  This will not work.  It must be set to AudioTrack (RAW), Android IEC packer as Android is mixing down the audio data into 2 channels for output over ARC, which only supports 2 audio channels.  This doesn’t mean we’re only sending Left and Right audio channels.  It just means we’re sending the encoded bitstream of 5-channel Dolby Digital data over one of these two channels.

“Dolby Digital (AC3) capable receiver” tells Kodi to output raw encoded Dolby Digital bitstream and that the device (your AV receiver) on the other end will perform the decoding.

“Enable Dolby Digital (AC3) transcoding”  will transcode DTS sound data into Dolby Digital AC3 for transport over the ARC audio channels.  Kodi, on Epson Android TV systems, does not currently support raw DTS audio data over ARC (as of Kodi 19.3 Matrix).  This is why we need Dolby Digital transcoding ON: we’re converting DTS into Dolby Digital AC3 5.1 signal.

“DTS capable receiver” OFF will force transcoding of DTS streams into DD AC3 streams since Kodi on Epson Android TV does not support DTS passthrough over ARC at this time.

So the big caveat with all this is: DTS cannot be directly output / passthrough as-is to your DTS receiver.  It must be transcoded from DTS into Dolby Digital.  It’ll still be 5.1 digital surround at least.

Also, Kodi on this Epson Android TV hardware cannot output anything but basic Dolby Digital AC3 5.1.  So no DTS HD, Dolby True HD, no E-AC3 nor Atmos.  Just basic Dolby Digital AC3 5.1.