[linux-audio-user] "PDAudio-CF on Laptop with Linux" Adventures

Daniel Zuckerman dzlinuxaudio at hemiola.org
Thu Nov 11 08:57:27 EST 2004


Greetings listers.

I thought I'd share some things I discovered last night.

After spending an inordinate amount of time (not all at one sitting) 
trying to figure out how to solve this problem...

~/test-alsa/ arecord -D pdaudiocf -f cd foo.wav
Recording WAVE 'foo.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, 
Stereo
arecord: pcm_read:1196: read error: Input/output error

...I made some discoveries.  This started happening to me after coming 
fresh to the laptop one evening, ready to transfer an old concert tape.  
The PDAudio-CF having worked like a champ before, I was starting to get 
nervous that something odd had happened.  Turns out, after going to the 
#alsa group on freenode and getting a huge amount of attention from one 
kind soul, who eventually pointed me to one of the alsa list archives, 
combined with something I seemed to recall reading somewhere, that the 
tape was at 48k, and the PDAudio-CF doesn't do hardware sample rate 
conversion.

So why I am I telling you this?

Well, for one thing, if my notes ever get deleted, I can always check 
this archive.  :)

But I hope to save someone else the problem.

WHAT TO DO:

So, if you get this error, and it seems out of the blue (like the thing 
was *just* working!!!),
Check what the card thinks the incoming sample rate is.  You can do this:
       amixer -c <card#> contents.
In there somewhere you'll see something about "IEC958 External Rate", 
and the next line will be the incoming sample rate (in samples/sec).  
you'll want to make sure that the incoming sample rate and outgoing 
sample rate are the same.  So in my case for last night, I needed to do 
the following with the 48k tape:
       arecord -c hw:1,0 -r 48000 -f dat foo.wav



BUT WAIT, THERE'S MORE:

Before I got to that solution, I found this nifty shell script in the 
alsa archives that let's you specify optical/coax input.  It 
automagically figures out which hardware slot the PDAudio-CF occupies.  
Here's a link the alsa archives message containing the script: 
http://sourceforge.net/mailarchive/message.php?msg_id=7502478


That's it for today.  I'm looking forward to recording my first live 
convert this weekend using this device (backed up with DAT just in case...)!

Regards,
Daniel Zuckerman



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