Raspbmc & audio 5.1 from jack 3.5

The audio jack supports analoge 2.0 only as far as i know. Maybe it would be possible to output electrical (non-optic) spdif through this or any other GPIO Pin, but I doubt that there are any drivers available yet. It sounds like an interesting project though.

You'll have to re-work your setup to use the HDMI sound from the Pi. Generally, TVs and media centres will accept analogue audio as an input but will not encode that as IEC-61937 digital audio for output to other units. They will, however, happily pass digital audio from input to output, whatever the cable type, be it HDMI, coax or optical. So you do need to start with digital audio.

That's not going to hapen the 5.1 is only on the HDMI.

Or set the Pi to output analogue 2.0 from the 3.5 mm jack, the default is generally sound and video on the HDMI. Not setting the audio to go out of the analogue 3.5 mm jack is proably why the OP, effectively, had no audio when he tried it.

But possibly not in the same format as is input. Our Panasonic only ever sends 2.0 out of the optical connection even when it's fed 5.1 up an HDMI input.

So, thanks to everybody for suggestions. It's clear that I could get only 2 .0 stereo sound as output from spdif terminal. That's good to build up a hi fi system or similar but not for home theater. In such case I need an ampli fier with hdmi input and internal decoder for ac3, dts, etc.

You can send ac3 sound encapsulated in a wave container via digital to a home theatre amp. I haven't tried this on a Raspberry Pi as I dont have a means to extract digital from HDMI. A modern set with HDMI input should be OK.

In linux playing software I think this is described as ac3 passthrough, In RISC OS I had to convert the AC3 file to send manually. ffmpeg (now avconv) can rip the ac3 track and convert it to the suitable s/pdif wav, and I also found a binary 'ac3spdif' from a different library works too.

Ron M.

You can only get stereo from the 3.5mm jack. There isn't a SPDIF terminal on the Pi. You might want to try a USB sound card which has suitable Linux drivers.

---druck