[alsa-devel] Juli@ ICE1724 and 24 bit audio

[Demian Martin]

Testing updates. 
First aplay w/ hw:0,0 gets this useless result:
linuxmce at dcerouter:/home/public/data/audio/RR HDaudio$ aplay -v -Dhw:0,0
1_Mystery_Pacific.wav                                      
Playing WAVE '01_Mystery_Pacific.wav' : Signed 24 bit Little Endian in
3bytes, Rate 176400 Hz, Stereo
aplay: set_params:900: Sample format non available

Then w/ plughw:0,0
linuxmce at dcerouter:/home/public/data/audio/RR HDaudio$ aplay -v -Dplughw:0,0
01_Mystery_Pacific.wav
Playing WAVE '01_Mystery_Pacific.wav' : Signed 24 bit Little Endian in
3bytes, Rate 176400 Hz, Stereo
Plug PCM: Linear conversion PCM (S32_LE)
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S24_3LE
  subformat    : STD
  channels     : 2
  rate         : 176400
  exact rate   : 176400 (176400/1)
  msbits       : 24
  buffer_size  : 32768
  period_size  : 8192
  period_time  : 46439
  tick_time    : 0
  tstamp_mode  : NONE
  period_step  : 1
  sleep_min    : 0
  avail_min    : 8192
  xfer_align   : 8192
  start_threshold  : 32768
  stop_threshold   : 32768
  silence_threshold: 0
  silence_size : 0
  boundary     : 1073741824
Slave: Hardware PCM card 0 'ESI Juli@' device 0 subdevice 0
Its setup is:
  stream       : PLAYBACK
  access       : MMAP_INTERLEAVED
  format       : S32_LE
  subformat    : STD
  channels     : 2
  rate         : 176400
  exact rate   : 176400 (176400/1)
  msbits       : 24
  buffer_size  : 32768
  period_size  : 8192
  period_time  : 46439
  tick_time    : 0
  tstamp_mode  : NONE
  period_step  : 1
  sleep_min    : 0
  avail_min    : 8192
  xfer_align   : 8192
  start_threshold  : 32768
  stop_threshold   : 32768
  silence_threshold: 0
  silence_size : 0
  boundary     : 1073741824
underrun!!! (at least 97.039 ms long)
Status:
  state       : XRUN
  trigger_time: 1234296814.359013515
  tstamp      : 1234296814.456029856
  delay       : 0
  avail       : 32768
  avail_max   : 32768
Aborted by signal Interrupt...

I have underrun issues I need to look into as well. Perhaps some buffer
setting needs to be changed? This is on a Via platform so it doesn't have a
whole lot of power. Any suggestions would be appreciated. That is an area
where I have gotten very lost in the past.


Demian Martin
Product Design Services
784 Cary Drive
San Leandro, CA 94577
209 613 6990


-----Original Message-----
From: Pavel Hofman [mailto:pavel.hofman at insite.cz] 
Sent: Tuesday, February 10, 2009 7:35 AM
To: Vedran Miletić
Cc: Demian Martin; alsa-devel at alsa-project.org
Subject: Re: [alsa-devel] Juli@ ICE1724 and 24 bit audio

What makes you guys think the plug plugin trims the data down to 16bits? 
  Sure if the rate is changed (the source code suggests only the 
low-quality linear rate algorithm supports above-16bit format - 
operation convert, the other resampling algorithms convert using the 
operation convert_s16).

Ice1724 supports all the general rates natively, the rate conversion in 
the plug plugin should not kick in for common audio formats. The only 
case I can think of would be switching Juli to external SPDIF-IN clock - 
the hw.rate_min = hw.rate_max = actual_rate and the automatic rate 
conversion could happen.

I did not use the hw device in my tests since all the tested tracks 
would have to be 32-bit for the hw device to accept the format when 
played via my favorite aplay.

My 2 cents guess is xine does the conversion.

Regards,

Pavel.