[MPlayer-dev-eng] Practical outcomes of the ALSA thread

[Thomas Orgis]

Am Sat, 5 May 2007 15:20:59 +0400
schrieb Vladimir Mosgalin <mosgalin at VM10124.spb.edu>: 

> Hi Thomas Orgis!
> 
>  On 2007.05.05 at 12:25:25 +0200, Thomas Orgis wrote next:
> 
> > $ mpg123 -a hw -v -v ...
> > High Performance MPEG 1.0/2.0/2.5 Audio Player for Layers 1, 2 and 3
> > 	version 0.65; written and copyright by Michael Hipp and others
> > 	free software (LGPL/GPL) without any warranty but with best wishes
> > 
> > Audio capabilities:
> >         |  s16  |  u16  |  u8   |  s8   | ulaw  | alaw  |
> >  --------------------------------------------------------
> >   8000  |   S   |       |       |       |       |       |
> 
> Wow! What a nice card do you have.

Heh, 

00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01)

ac97_codec: AC97 Audio codec, id: ADS116 (Analog Devices AD1981B)

I guess you'd like to rephrase to "what a crappy onboard chip";-)
Well, an old AWE32 (or 64, not sure now) is a bit more flexible

        |  s16  |  u16  |  u8   |  s8   | ulaw  | alaw  |
 --------------------------------------------------------
  8000  |  M/S  |  M/S  |       |       |       |       |
 11025  |  M/S  |  M/S  |       |       |       |       |
 12000  |  M/S  |  M/S  |       |       |       |       |
 16000  |  M/S  |  M/S  |       |       |       |       |
 22050  |  M/S  |  M/S  |       |       |       |       |
 24000  |  M/S  |  M/S  |       |       |       |       |
 32000  |  M/S  |  M/S  |       |       |       |       |
 44100  |  M/S  |  M/S  |       |       |       |       |
 48000  |       |       |       |       |       |       |

I bet that the SBLive in another box will fill the 48Khz entries with M/S.
But it looks like that this D/A flexibility (which makes darned sense to
have in hardware) is a thing of the past, when the modern expensive gear
...

> Audigy 2ZS p16v device (the only way to get higher than 48khz and
> bit-accurate playback):
> $ mpg123 -a hw:0,4 -v -v jjj_19.mp3 
[empty table]

Uh... so I'd have to add 96KHz to the table to see some hardware support?
But then, will it do stereo or only surround?
I must admit that I'd have to extend mpg123's resampling support to produce
96KHz (no big deal, though). Currently, transparent resampling through
ALSA is a real benefit for you there. Fact.
Hm, looking at specs... the card doesn't even support 16bit samples, eh?

Well, your case is then one which really, really, needs software resampling
for common music / video files.
That's indeed sad, as a 44100Hz file won't sound like 96000Hz when
interpolated, actually, it will sound worse unless the software closely models
the behaviour of a d/a circuit with the correct clocking.
You have this shiny enthusiast audio equipment and the CD-Audio music
library possibly sounds worse than played by a good old AWE32...

But when you purchase an Audigy 2ZS for the laptop (perhaps I'll get something
similar in future, even), it's possibly more about recording/authoring than
listening to your mp3 colleciton.
There I'd use 24bit and highest rate only anyway.


Thomas.
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