On 22/04/18 13:14, Marc Haber wrote:
On Sun, Apr 08, 2018 at 05:20:13PM +0100, James wrote:
On 31/03/18 20:02, Marc Haber wrote:
In order to get output to the digital output, you need to use the "iec958"
device.
E.g.:
speaker-test -c2 -d iec958:CARD=CMI8738,DEV=0 --rate 48000
Note that you also appear to have a digital out of the SB card, so you need
to select the card when outputting.
That would be CARD=Device to use the USB Device, and that actually
works. --rate 44100 does not seem to work. Is it possible that the USB
device is only able to play back at 48 kHz so that the PC needs to
resample, or can this be a driver issue that the frequency is not
correctly selected?
And even after successful playback with --rate 48000 and the DAT deck
still being synced to the input, iecset -c iec958:CARD=Device,DEV=0 says
Rate: 44100.
You might also need to mess with AES0 settings. Google for that.
Google results are inconclusive, a ton of forum entries like
"AES0=number fixed it for me", but nothing resembling an explanation,
and nothing in the Documentation subdirectory in the kernel tree.
Greetings
Marc
Ok, so you are making some progress and have 48000 working.
iecset is only useful up to a point. It tells you the settings when
idle. They get overridden when you play something.
iec958:AES0=0x6,AES1=0x82,AES2=0x0,AES3=0x2
Those are the AES settings, in this case for AC3 encoding.
The numbers change depending on the format of the output.
The default is right for 48000 rate PCM, you will need different bits
set for 44100.
One way of finding the right string is to type "iecset", it will
describe the bits. then typing "iecset -x" will tell you which AES0
values match it.
Some playing with iecset gives the following:
AC3
AES0=0x6,AES1=0x82,AES2=0x0,AES3=0x2
44100
AES0=0x04,AES1=0x00,AES2=0x00,AES3=0x00
48000
AES0=0x04,AES1=0x00,AES2=0x00,AES3=0x02
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