Re: USB recording - repetitive peaks

[Takashi Iwai <tiwai@suse.de>]

Hi Patrick,

i found out an obvious bug there.  i forgot to correct the offset
value of capture destination after a minor modification.
it's fixed on cvs.
could you update the cvs and test whether it works?


Takashi


At Wed, 03 Jul 2002 00:35:03 +0900,
Patrick Shirkey wrote:
> 
> Takashi Iwai wrote:
> > Hi Patrick,
> > 
> > At Tue, 02 Jul 2002 23:28:08 +0900,
> > Patrick Shirkey wrote:
> > 
> >>Thanks to your patch Takashi we have two people who have been able to 
> >>record through the quattro.
> >>
> >>We have both found that there is a constant repetitive peak in the 
> >>signal which reminds me of the problems I had with the cmipci for a 
> >>brief period.
> >>
> >>Thorsten Hass has recorded a perfect example for you which he did using 
> >>aplay and arecord. It is a sine wave so is easy on the ears.
> >>
> >>http://www.thorstenhaas.de/alsa/audio.file
> > 
> >  
> > hmm, this sounds like the mismatching of packet size and copy
> > destination.  i heard your ogg file, and this was similar, too.
> > 
> > under which condition were they recorded?
> > with 24bit/96kHz/2ch?
> > or does it happen generally on every condition?
> > 
> 
> They were arecord -f cd
> 
> > you can see the running status and condition on streamX proc file
> > during playback/capture.
> > 
> 
> ----
> # cat /proc/asound/card2/stream1
> M Audio USB AudioSport Quattro (tm) : USB Audio #1
> 
> Playback:
>    Status: Stop
>    Altset 3
>      Format: S16_LE
>      Channels: 2
>      Endpoint: 3 OUT (ADAPTIVE)
>      Rates: 11025, 22050, 44100, 48000
>    Altset 2
>      Format: S24_3LE
>      Channels: 2
>      Endpoint: 3 OUT (ADAPTIVE)
>      Rates: 11025, 22050, 44100, 48000
>    Altset 1
>      Format: S24_3LE
>      Channels: 2
>      Endpoint: 3 OUT (ADAPTIVE)
>      Rates: 88200, 96000
> 
> Capture:
>    Status: Running
>      Packets = 20
>      URBs = 5
>      Packet Size = 192
>      Nominal freq = 44.          1682  Altset 3
>      Format: S16_LE
>      Channels: 2
>      Endpoint: 5 IN (SYNC)
>      Rates: 11025, 22050, 44100, 48000
>    Altset 2
>      Format: S24_3LE
>      Channels: 2
>      Endpoint: 5 IN (SYNC)
>      Rates: 11025, 22050, 44100, 48000
>    Altset 1
>      Format: S24_3LE
>      Channels: 2
>      Endpoint: 5 IN (SYNC)
>      Rates: 88200, 96000
> 
> ----
> 
> 
> > 
> > 
> >>He has also generated a jpeg plotted by an oscilloscope while recording 
> >>which I can send you if it will help.
> > 
> > 
> > can you figure out how long the period of puls is?
> 
> They are so regular you can set a use them as a metronome:) Would you 
> like me to have a look at the timing in an editor or is there an more 
> precise way to find out?
> 
> > i guess this has relation between the status shown in the proc file
> > above.
> > 
> > 
> > Takashi
> > 
> > 
> 
> 
> 
> -- 
> Patrick Shirkey - Boost Hardware Ltd.
> For the discerning hardware connoisseur
> Http://www.boosthardware.com
> Http://www.boosthardware.com/LAU/guide/
> ========================================
> 


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