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Digi +IO driver question

Uli Brüggemann

September 10, 2020 12:38

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Hello,

I have a problem with 24bit resolution for Digi +IO.

 

Background: some time ago I have used the Digi in combination with the hifiberry-digi.c driver and Brutefir. In Brutefir I have selected S32_LE as resolution for input and output. The old software is still working BTW.

 

Now when I try to set up a newer system, e.g. the latest Raspbian or PiCore, I cannot select S32_LE anymore. Also S24_xLE does not work. ONLY S16_LE is working correctly but it is obviously restricted to 16 bits resolution.

Brutefir brings up an error message, the format S32_LE is invalid.

Now the driver has changed to the general rpi-WM8804-soundcard.c driver. Is this the possible reason?

How to fix the problem.? Of course I still like to send also Music data with 24bit resolution.

Any idea about this?

 

BR

Uli

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2 comments

• 0
  
  HiFiBerry team September 10, 2020 13:19

  Nothing has changed on the driver - at least not with the supported sample formats. I would guess that some process already accesses the sound card:
  https://www.hifiberry.com/docs/software/check-if-the-sound-card-is-in-use/
  
  However, I can't help with specific BruteFir configuration questions.

• 0
  
  Uli Brüggemann September 10, 2020 13:41

  Thanks.

  There is no 2nd process accessing the soundcard.

  As already said using Brutefir with S16_LE Format properly works.

   

  In the meantime I have done some tests with aplay and verbose output (on latest Rasbian):

  aplay -c 2 -r 44100 -f S32_LE -v Test.wav

  results in

   

  Warning: format is changed to S24_3LE
  Playing WAVE 'Test.wav' : Signed 24 bit Little Endian in 3bytes, Rate 44100 Hz, Stereo
  Plug PCM: Linear conversion PCM (S24_LE)
  Its setup is:
    stream       : PLAYBACK
    access       : RW_INTERLEAVED
    format       : S24_3LE
    subformat    : STD
    channels     : 2
    rate         : 44100
    exact rate   : 44100 (44100/1)
    msbits       : 24
    buffer_size  : 22052
    period_size  : 5513
    period_time  : 125011
    tstamp_mode  : NONE
    tstamp_type  : MONOTONIC
    period_step  : 1
    avail_min    : 5513
    period_event : 0
    start_threshold  : 22052
    stop_threshold   : 22052
    silence_threshold: 0
    silence_size : 0
    boundary     : 1445199872
  Slave: Hardware PCM card 0 'snd_rpi_hifiberry_digi' device 0 subdevice 0
  Its setup is:
    stream       : PLAYBACK
    access       : MMAP_INTERLEAVED
    format       : S24_LE
    subformat    : STD
    channels     : 2
    rate         : 44100

   

  So clearly it is not a problem of the soundcard, its driver or ALSA. I guess I need to find some support for Brutefir.

   

  BR

  Uli