Re: [Protux-devel] Status/implementation multiple bitdepth/samplerate etc. support

[Luciano Giordana]

>
> 1.
> SND_PCM_FORMAT_S32_LE --- the actual bitdepth can be (16?? or) 24 bits, but
> stored in a "word". The card internally handles all samples with 32 bits at
> a time. There is no "real" 32 bit support (DAC, ADC are 24 bits)

I started the several-bitdephts/formats supports, but I had to interrupt it. I 
will get back on this soon.

>
> 2.
> Any of the following rates can be used both in stereo and mono:
> 44100,
> 48000
> 96000
>
> 3.
> And last but not least, the card can handle up to:
> 10 channels.

== 10 mono buses ? (in mutux terminology) or 5 stereo ?


> Setting the hw_param values must be done with one of the values from the
> points 1-3
>
> This card has physically only 2 channels, but the chip can handle 10
> channels, so the "hw" wants to have it set to 10!!
>
> MADM and MustuxAudioBus are still not prepared to handle this situation.
>
> So my suggestion in this is:
> Detect the cards "real" bitdepth, channels, and rate support, test these
> values with MustuxAudioBus::supports (or place this detection code in this
> method).

I thought It was doing it ... :-(

> Then we have a "real supported" bitdepths, rate and channels for MADM, and
> if a given samplerate from Mixer doesn't match the "real supported" etc,
> then convert it to a rate which is supported by MADM (and thus by the audio
> card) Only in this way we can use the "hw" descriptor, else I have to use
> "plughw" for ever, even if protux has internal 24 bits, etc... support.

dynamic activation of plughw was one of my plans. But, as you said, they say it 
is good to
avoid plughw, specially in professional environment...

>
> Plughw is less robust, (that's what they say on the alsa-devel and
> sound-devel mailing lists) and if we do it internally in MADM, or
> MustuxAudioBus, I really should be happy, as I still get alsa-lib errors
> when I start a recording.
I agree. As I said, I plan to finish the multi-bitdepth/rates very soon 
(perheps next week already,
when my gig is done)


[]s