The I2S interface is still present on the 40-pin GPIO as per the Pi2 and B+.

Thanks for the information, I was under the impression that the Pi 2 also used P5... but indeed it's on the 40 pin header now (http://www.pagemac.com/projects/i2s_amp)

Now if one could repurpose another 2 GPIO pins for bit-banging I2s... there are chips which support multichannel, see http://www.ti.com/lit/an/snla221/snla221.pdf page 5.

If you have the technical skills to make it work it might be worth looking into the AC97 interface on some of the Allwinner boards. I'm not sure anyone's tried using it yet and some driver development will be required though.

Cheers for clarifying that. Might have been the end for hifiberry, iqaudio etc otherwise

Was there a seperate I2S connector or do you mean they're not routing those connections to the GPIO any more? I believe this board: https://www.hifiberry.com/ and the various other similar boards just connect via GPIO and use I2S

Doesnt HDMI audio provide as good quality as any i2s connector? Or do you just need i2s for interfacing with your own microcontrollers/older recieviers, which dont necessarily have hdmi (and thus copyright compliance, making it more expensive)?

Last I read Raspberry Pi should allow for 5.1 hdmi passthrough or at least DTS.

HDMI audio requires an extractor (so one more wall wart + device), and I'm using a Pi2 for home cinema. And I'm one of those with an "old" HiFi setup without digital input, just analog.

So use an old RPi? Or a Model B?

It does and that's how I have it set up. RPi source to receiver over HDMI. DTS 1080p movies playback beautifully with a slight overclock (on an original B).

RPI's hardware doesn't support DTS-HD MA or Dolby TrueHD passthrough though :(

Hang on, really? So there is no scope for any sort of compact HifiBerry-like dac with a Pi3?

There are pads underneath the antenna on the reverse side of the board, so it is possible to add an external antenna with some hacking.