[alsa-devel] Adding a "capture" device naming scheme

Colin Guthrie gmane at colin.guthr.ie
Wed Jan 12 10:04:29 CET 2011

'Twas brillig, and Raymond Yau at 12/01/11 08:38 did gyre and gimble:
> 2011/1/12 Takashi Iwai <tiwai at suse.de>
>> At Wed, 12 Jan 2011 09:08:37 +0800,
>> Raymond Yau wrote:
>>> 2011/1/12 Colin Guthrie <gmane at colin.guthr.ie>
>>>> Hi,
>>>> As has been pointed out a few times, it's incorrect to use "front:" for
>>>> capture, but can we have an official name/wrapper (I'm unsure of the
>>>> terminology here) for this so we don't use hw: for recording?
>>>> I'd be in favour of "capture:" or "input:" as these both seem quite
>>>> logical and easy to understand.
>>>> It would be used thusly:
>>>>  arecord -f S16_LE -c 2 -D capture:CARD=Intel
>>>> as opposed to the incorrect:
>>>>  arecord -f S16_LE -c 2 -D front:CARD=Intel
>>>> or the low level:
>>>>  arecord -f S16_LE -c 2 -D hw:CARD=Intel
>>> why do you think that it is incorrect to use hw:CARD=xxx for analog
>> capture
>>> ?
>> I read Colin meant front:CARD=x is incorrect while hw:CARD is a lowlevel
>> access that one doesn't always want.
>> I'm fine with creating a new name, but wondering which name is best.
>> Basically what you want here is the default use-case but without
>> dsnoop like the current "default".  (If dsnoop were acceptable,
>> "default" should have been used in most places.)
>> "capture" may be also too ambiguous for defining that, I'm afraid.
>> thanks,
>> Takashi
> Does all HDA codec support multistreaming capture since HDA spec seem have a
> limitation on the number of capture stream or just ALSA does not support
> multistreaming ?
> http://www.intel.com/support/motherboards/desktop/sb/cs-020642.htm
> #multistream
> some realtek codec put another analog capture device at hw:0,2
> It seem that some VIA codec support "multistreaming" capture since it  has
> an indepedent ADC which can only connect to the front panel mic and the
> driver create have two subdevices
> As device 0 support multi channels but those alternate stream support stereo
> only
> can the HDA driver assign analog_alt_playback and analog_alt_capture in the
> same device ?

All of this is very interesting Raymond, but please don't hijack this
thread to discuss something different.



Colin Guthrie

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