linuxaudio.org

On July 26, 2010 09:07:35 pm you wrote:

quoted text
> On Mon, Jul 26, 2010 at 12:29 AM, Tim E. Real  wrote:

> >  trust me it will look great at the expense of only 28 extra pixels for

> >  the minimum height over the original - it's all you can really do, man:

> >

> > Remove the -72 and -108 dB marks on all the monitor sliders

> >  in volume.c: draw_24bit_attenuator_scale_markings().

> >

> > Remove the -42 and -54 dB marks from the DAC sliders in

> >  volume.c: draw_dac_scale_markings().

> >

> > Remove the -18, -30, -42, -54, -60 dB markings from the ADC

> >  sliders in volume.c:draw_adc_scale_markings().

> >

> > Change the level meter heights by changing

> >  gtk_widget_set_usize(drawing, 24, (60 * tall_equal_mixer_ht + 204));

> >  to

> >  gtk_widget_set_usize(drawing, 24, (60 * tall_equal_mixer_ht + 168));

> >

> >  in envy24control.c: create_mixer_frame().

> >

> > Trust me they'll love it !

>

> Thanks! Yes, it does look better. I've applied these suggestions to my

> current sources and they'll be part of an upcoming release that

> addresses the issues...

>

> If you have any suggestions on getting rid of the annoying

> detent/hysteresis as you move the sliders past the markings, that

> would be great.

>

> -- Niels.

> http://nielsmayer.com

Sure, NP I'll take a look.
Good news!

As I mentioned in a follow-up to another thread, I found a bunch

 more dB related functions.
I tested replacing the code in volume.c:dac_volume_to_db() and

 adc_volume_to_db() with a call to ALSA's snd_ctl_convert_to_dB().
The results are identical! And better for ADC compatibility, right?
Now comes the fun part. Coming up with an Al-Gore-rithm to

 handle the scale markings using these ALSA functions -

 how many 6dB steps we have, which ones to display, the range, etc.
It occurred to me 'dynamic markings': If the user expands

 more, or less, vertically, then more, or less, markings should appear.

But it's still tricky - we want it to look the way I suggested above,

 with more markings concentrated around the 0dB point, whenever

 we are forced to compromise by removing marks.

Ultimately, at minimum height it must look like that - it's a compromise,

 until a (better) solution comes up.
Also I see there is something called TLV based dB conversion where

 I think it's a table or can be an arbitrary function. Must study more.
------------

For now here's the code, throw it inside

 dac_volume_to_db() and

 adc_volume_to_db() but *replace* DAC_VOLUME_NAME with ADC_VOLUME_NAME,

 and I believe mixer_volume_to_db() and wherever else required.

Do you need a patch?
Hope this is OK, not sure how many members to set in struct snd_ctl_elem_id.

List members, does it look OK?
char* dac_volume_to_db(int ival) {

 if (ival != 0) {
  // Use ALSA functions to get dB values.

  long db_gain = 0;

  float fval;

  snd_ctl_elem_id_t *elem_id;

  snd_ctl_elem_id_alloca(&elem_id);

  snd_ctl_elem_id_clear(elem_id);

  snd_ctl_elem_id_set_interface(elem_id, SND_CTL_ELEM_IFACE_MIXER);

  snd_ctl_elem_id_set_name(elem_id, DAC_VOLUME_NAME);

  snd_ctl_convert_to_dB(ctl, elem_id, ival, &db_gain);

  fval = ((float)db_gain / 100.0);

  sprintf(temp_label, "%+2.1f", fval);

  return (temp_label) ;
 }

 else

 {

    // Rest of function ('off' part). ]

   ...
Tim.
_______________________________________________

Linux-audio-dev mailing list

Linux-audio-dev@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-dev