Re: 5.1 interfaces.
Re: 5.1 interfaces.
- Subject: Re: 5.1 interfaces.
- From: Brian Willoughby <email@hidden>
- Date: Fri, 11 Oct 2002 16:42:01 -0700
Mark Cookson <email@hidden> wrote:
[ The M-Audio Sonica, a USB to S/P-DIF device, will let you output
[ AC-3 to your home stereo decoder via its optical output.
I just heard about the M-Audio Sonica, but there doesn't seem to be enough
in-depth information on their site or in their press release. Does this device
*create* an AC-3 stream from 6 discrete PCM channels sent to CoreAudio? ...
or does it merely pass through an AC-3 stream that already exists - e.g. from a
DVD soundtrack file?
The Sonica also claims to "support" DTS, but I could not determine whether it
will create / encode DTS or merely pass it through like a consumer DVD player
with DTS support.
What I would like is to be able to line up six tracks of PCM audio in Logic
Audio Platinum, and play it through some device which will encode to DTS
(rarely would I choose AC-3) to my surround decoder which accepts PCM, AC-3,
and DTS.
Will CoreAudio ever have converters / encoders that accept 6 channels (or 4)
and output a stream in DTS or AC-3 (CBR)? Will there be control over bit rate
- e.g. DTS supports 1536 kbps (48 kHz), 1411.2 kbps (44.1 kHz), and 768 kbps
(half-rate DTS for DVD with 5.1 AC-3 sharing the limited bandwidth).
[ The emagic emi 2|6, a USB device, has 6 outputs which would allow
[ you to output 6 channels of PCM audio to anything that accepts
[ line level inputs.
Theoretically, the EMI 2|6 should support DTS and AC-3 if you hand it a
pre-encoded stream at the right bit rate. There are S/P-DIF in and out
connectors which I use almost exclusively. It seems that a software DVD player
could leverage the eMagic hardware to output 5.1 to an outboard decoder. I
don't think the EMI 2|6 supports the half-rate DTS clock rate, though, but I'm
sure they could add that with a firmware driver update. Of course, if you're
happy with 24-bit analog outputs, and have a software decoder, the EMI 2|6
could certainly handle driving 5.1 analog inputs on a surround system.
Brian Willoughby
Sound Consulting
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