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[ths61]

Can MC output in 64-bit or is 32-bit the max ?

Thanks much.

[JimH]

I assume you mean audio.  MC will output whatever the device and its driver support.

[ths61]

I assume you mean audio.  MC will output whatever the device and its driver support.

JimH, thanks much. 

I am trying to output JRMC28 AUDIO to Alsa_cdsp (an ALSA I/O plugin), then CamillaDSP in FLOAT64_LE on Debian 11-64 (kernel 5.14) and finally to the 8 channel DAC (same behavior on Debian 10-64 with JRMC26 and JRMC27).

https://github.com/scripple/alsa_cdsp

https://github.com/HEnquist/camilladsp

When I select Alsa_cdsp as the AUDIO output device, JRMC28's "Device Settings/PCM Output Format" pulldown list only shows 4 (of 6) specific formats (Auto, S32_LE, S24_3LE, S24_LE and S16_LE). 

FLOAT_LE and FLOAT64_LE are NOT listed as options.

Alsa_cdsp supposedly publishes(via SND_PCM_IOPLUG_HW_FORMAT) the following 6 supported PCM I/O MUSIC formats (same formats as CamillaDSP).  S32_LE is the largest format presented in the MC[26,27,28] pulldown list (and works with that format).

Code: [Select]

  // Configure "hw" constraints
  unsigned int format_list[] = {
    SND_PCM_FORMAT_S16_LE,
    SND_PCM_FORMAT_S24_LE,
    SND_PCM_FORMAT_S24_3LE,
    SND_PCM_FORMAT_S32_LE,
    SND_PCM_FORMAT_FLOAT_LE,
    SND_PCM_FORMAT_FLOAT64_LE
  };

  snd_pcm_ioplug_set_param_list(&pcm->io, SND_PCM_IOPLUG_HW_FORMAT, 6, format_list);

Do you have any idea why FLOAT_LE and FLOAT64_LE are not offered in the JRMC28's "PCM Output Format" list ?

I would like to not drop down to 32 bits if possible.

Thanks again

[ths61]

UPDATE:

I tried 2 USB DACs and onboard audio.  I get the same 4 options in JRMC28 no matter what audio device I select.

I updated the alsa_cdsp plugin code to only publish 1 format (S16_LE) and installed it.  JRMC28 still offers the same 4 options after reboot even though only 1 is published. 

I also tried adding in 2 more options for a total of 8 and the pull down list still displays the same 4 options after reboot even though 8 are published. 

There does not appear to be a correlation between the ALSA PCM plugin's published formats and the JRMC28 pulldown list.

Should this be flagged as a bug ?
 

Code: [Select]

// Configure "hw" constraints
  unsigned int format_list[] = {
    SND_PCM_FORMAT_S16_LE
  };

  snd_pcm_ioplug_set_param_list(&pcm->io, SND_PCM_IOPLUG_HW_FORMAT, 1, format_list);


[Awesome Donkey]

What DAC are you using? All the DACs I've used or seen max out with 32-bit bit-depth support.

[ths61]

What DAC are you using? All the DACs I've used or seen max out with 32-bit bit-depth support.

Hi Awesome Donkey,

It is the ALSA PCM Plugins that have the FLOAT64 interfaces that JRMC28 writes to. 

The plugin is specified in JRMC28 as the target output "device", not a specific hardware DAC.  The hardware DAC is specified in camillaDSP's plugin configuration at then end of the signal processing chain, thus should be hidden (twice removed) from JRMC28 and (once removed) from the Alsa_cdsp plugin that JRMC28 is writing to.  Both of the ALSA PCM plugins support FLOAT64 which is not offered in the pulldown menu.

I am trying to combine JRMC28's 64-bit volume control with the plugins' 64-bit processing without "thunking" (old Windows term) down to 32-bit in the middle of the signal processing chain.  All of the FIR filters are built in 64-bit.

It appears JRMC28 is using a pre-canned list of menu options because they do not reflect the differences (as shown in alsacap's list) in the various audio cards that I have tried (Gigabyte's onboard sound, W4S DAC2-DSDSE, W4S µDAC, Khadas Tone Board DAC and Okto Research DAC8).

Does the JRMC2X Linux code query and try to use the plugin's published feature set (i.e. in the "AUTO" setting) ?

Thanks much.

[ths61]

....  MC will output whatever the device and its driver support.

Update:
All 6 of the ALSA plugin's published formats are found by the open source aplay test(/dev/zero) CLI dump command. 
Being open source, the code is readily available on how to query an ALSA plugin's feature set.

aplay -v -D camilladsp /dev/zero --dump-hw-params
Playing raw data '/dev/zero' : Unsigned 8 bit, Rate 8000 Hz, Mono
HW Params of device "camilladsp":
--------------------
ACCESS:  MMAP_INTERLEAVED MMAP_NONINTERLEAVED MMAP_COMPLEX RW_INTERLEAVED RW_NONINTERLEAVED
FORMAT:  S16_LE S24_LE S32_LE FLOAT_LE FLOAT64_LE S24_3LE
SUBFORMAT:  STD
SAMPLE_BITS: [16 64]
FRAME_BITS: [128 512]
CHANNELS: 8
RATE: [44100 384000]
PERIOD_TIME: [625 23220)
PERIOD_SIZE: [240 1024]
PERIOD_BYTES: [15360 16384]
PERIODS: [2 8]
BUFFER_TIME: [1250 185760)
BUFFER_SIZE: [480 8192]
BUFFER_BYTES: [30720 131072]
TICK_TIME: ALL
--------------------
Available formats:
- S16_LE
- S24_LE
- S32_LE
- FLOAT_LE
- FLOAT64_LE
- S24_3LE

[bob]

Added these formats to MC29.