Re: [ARMini-support] ARMX6 USB-audio capable ROM now available (also SPI)
- From: Jim Lesurf <jcgl@xxxxxxxxxxxxxxx>
- To: <armini-support@xxxxxxxxxxxxx>
- Date: Sat, 12 Mar 2016 17:03:43 +0000 (GMT)
In article <15b7c15f55.GrahameParish@grahame.parish>, Grahame
<grahame.parish@xxxxxxxxxxxxxxx> wrote:
Is there some setting to choose between analogue and USB audio output
from the system sounds?
No, I'm afraid not. As things stand the USB Audio is an *entirely seperate*
system to the rest of the RO Sound System (ROSS). That means that as
things stand programs like !DigitalCD or !PlaySound won't drive the USB
Audio.
To play (or record) audio using a USB device you currently have to use the
demo programs Colin, Dave, or I wrote. That in turn limits you to plain
wave files. I'm sorry this is currently so limited, but it does at least
give superb results when used.
If you get Colin's zip (linked from my software page) you can use his
!isocPlayer application. But you do *not* need to softload his modules if
you've installed the 'usbaudB' as that's already installed them for you.
You *do* however need to load Dave's USBAudio module (again from a zip
linked from my page) to use my programs. Colin's don't need this.
The reasons for this can be summarised fairly simply. Note I'm giving my
views here. So apologies to Andrew if he feels this isn't the place to do
so, and he may not share my views. But it may help people see where I am
'coming from'...
Colin has focussed on working out and enabling the USB Audio devices to be
'accessible'. His modules provide a 'DeviceFS like' interface. He has also
provide a simple player and recorder that uses this.
Dave has written his USBModule. (And a demo player that uses it.) This
provides a much nicer API for programmers.
I then wrote a 'demo' player and recorder which have a few more 'features'
than the above programs, and which uses Dave's module.
We all would *like* this to also be useable via the standard 'ROSS' so that
users could then use it via programs like !DigitalCD. However there have
been various reasons why this hasn't happened.
Firstly, a lot of work would be required when ROOL, etc, understandably
felt they had more urgent things to do *particular* when the 'demand' for
USB Audio seemed to be small. (Note the chicken and egg conundrum here.)
Secondly, good quality USB Audio means being able to play and process the
audio as 24bit samples. Yet the current system is all limited to a max of
16bit samples. (The mainboard hardware on modern kit like the ARMiniX, etc,
is internally 24bit. So in the long run we need this anyway. But as things
stand RO can only convey 16bit samples to it!) That means even *more* work
if we want full integration of USB Audio without loss of capability.
(Chicken and egg again.)
Colin and Dave's modules currently bypass the standard sound system. So
aren't subject to the 16bit limitation. Hence they can play and record 24
bit (and 32bit) samples with full quality, given the right USB Device.
In the main, only three people have worked on this until now. Being a
rubbish programmer I could just manage a very simple pair of 'demo'
programs. The aim being that this might 'bootstrap' interest by people who
like what they then can hear (and record) and may work on better programs
*and* show that there is a wider interest in putting "find the chicken"
somewhere higher on the "to do" lists... 8-]
In terms of results, you can now use the USB Audio with suitable hardware
to play up to 192k sample rate, 24 bit stereo wave files. You can also
record up to that with suitable kit. But as things stand the user software
is limited and bit clunky to use.
FWIW I may try myself to make a better player. Step one being able to play
wave files that have added metadata in their headers. (At present you need
to use my WAV_Cleaner prog on this first as the metadata confuses my
player.) Step two, I hope, will be to make flac files playable. (There is
already a way of doing this, but it involves commands in taskwindows.)
But I suspect the RO world would be better off if someone with more clue
than me did better players and recorder! Which brings me back to finding
more people willing to help with finding chickens...
The bottom line is that we probably need more people to either keep saying
they'd *like* 24 bit audio and USB audio for the standard 'ROSS' and/or
have a few more programmers (cleverer than me) to join in working on this
area. e.g. For all I know it may now be possible for someone to write a
'driver' module for !DigitalCD that lets it play 'direct' to USB Audio.
That would be brilliant. But knowing about that or doing it are *way* above
my abilities.
BTW so far, so good. I've been using the 'B' install and not yet seen any
problems. Fingers crossed. :-)
Jim
--
Electronics
http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Audio Misc
http://www.audiomisc.co.uk/index.html
Armstrong Audio
http://www.audiomisc.co.uk/Armstrong/armstrong.html
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