Re: Outputting multichannel sound through the optical link??
Re: Outputting multichannel sound through the optical link??
- Subject: Re: Outputting multichannel sound through the optical link??
- From: William Stewart <email@hidden>
- Date: Tue, 9 Feb 2010 18:05:17 -0800
I think I've been clear in my statements about what we have supported
in released products.
I see little future for SPDIF - you can't even use it to reliably
transfer 24bit audio at 48kHz - and there is no discovery mode that
can tell you whether what you are doing is even supported or
possible... It is quite possible to output Dolby Digital or DTS over
spdif and listen to very nasty noise.... To make a better user
experience you really need to know what the capabilities of the
devices are - so the EDID mechanism of HDMI/DP is a fine solution to
this. ADAT is even worse than SPDIF from a compatibility point of view
(less devices support it), so I see no future in this.
As Brian also pointed out, you are tending to gloss over the hardware
issues. But these are real limitations we have to deal with. With the
emerging availability of HDMI and DP we can see an end in sight to a
reasonable solution for multichannel audio in the consumer space.
On Feb 8, 2010, at 11:10 PM, Simon Thorpe wrote:
I have just seen that there is another company that makes Mini
Display
Port to HDMI connectors, but in this case, they include
connections to
allow the sound to be output too. There are two versions, one that
uses
the TosLink connector
(ttp://www.monoprice.com/products/product.asp?c_id=104&cp_id=10428&cs_id=1042802&p_id=6331&seq=1&format=2
) and one that used a USB connection
(http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10428&cs_id=1042802&p_id=5969&seq=1&format=2
).
I was hoping someone would make something like this...
I don't know of anyone who has tried this yet, but we will!
I also don't see any reason why your Mac (through the USB interface)
couldn't be seeing multi-channel audio as USB had the bandwidth to
carry it. So, if they've done this right, this is indeed an
interesting product. Thanks for the link
Bill
Bill
This is all very encouraging. First, the fact that a simple Mini
Display
Port to HDMI (from Griffin) works for new iMacs is great news.
Second, the
fact that the two Monoprice adapters can potentially work for all the
other machines with the Mini Display Adapters is also very positive.
I've
ordered one with USB and will let you know what happens (when it gets
delivered from the US). But since there are already 136 users who have
given the connector a very positive rating on their website, there are
presumably people out there who might already know the answer.
But it seems to me that Apple should really do their best to get
this to
work. If Core Audio needs updating so that a Home Theatre Amplifier
can be
recognised via the USB port HDMI link and configured for 5.1
(hopefully
7.1) sound, then surely that should be possible. That really is just a
software issue.
This will be a matter for this particular hardware. You can already
plug in multichannel USB interfaces (you have been able to do this for
10 years now!!!). If the manufacturer of the hardware has chosen to
provide multichannel audio in their interface, then it will come
through core audio just fine. My suspicion is that the interface will
only provide you stereo because they haven't noted anywhere that it
does multichannel. But hey, I might be wrong!
But what about allowing the Optical connector to stream to the HDMI
audio
too? My understanding is that the difference between SPDIF and an ADAT
Lightpipe (which can do 8 channels of 48 KHz 24 bit audio)
what's wrong with USB? Why make this more difficult than it needs to
be and inherit all of the problems that ADAT brings?
might well be
just a software issue. At least on my M-Audio Firewire 1814, you can
choose between using the optical links as SPDIF and ADAT under
software
control. Maybe a relatively simple modification would allow the
TosLink
based HDMI solution to work too.
Anyway, either USB or Optical or both should be possible. The only
thing
that is needed is for someone to do another Display Port + USB(or
optical)
to HDMI convertor for all those users with either (a) the old Mac
Display
ports, or (b) DVI ports. Hey, why don't Apple market such devices
themselves??
Simon
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