Noise Problem

Noise Problem

[Gerhard Dirschl]

 Hi.

I've tried to record a few samples with my M-Audio Audiophile using the
following settings:
Format: 24_3LE, 2 channels, sampling rate 48 kHz, pcm device
pcm.hwmix {
    type plug
    slave {
        pcm "hw:0,0"
        format S32_LE
    }
    ttable.0.10 1
    ttable.1.11 1
}

At the first view everything looked fine, but dragging down all sliders in 
the mixer, there was still a noise at approx. -80dB on channel 1, while 
channel 0 was far bellow -100dB.
The noise has gone, as I changed the above routing table something like this
ttable.0.10 1
ttable.0.8  0.01
ttable.1.11 1
ttable.1.7  0.01

There seems to be a flaw in pcm_route: 
@@ -790,15 +792,7 @@
 #endif
 		dptr->att = att;
 		dptr->nsrcs = nsrcs;
-		if (nsrcs == 0)
-			dptr->func = snd_pcm_route_convert1_zero;
-		else if (nsrcs == 1 && !att) {
-			if (params->use_getput)
-				dptr->func = snd_pcm_route_convert1_one_getput;
-			else
-				dptr->func = snd_pcm_route_convert1_one;
-		} else
-			dptr->func = snd_pcm_route_convert1_many;
+		dptr->func = snd_pcm_route_convert1_many;
 		if (nsrcs > 0) {
 			dptr->srcs = calloc((unsigned int) nsrcs, sizeof(*srcs));
 			if (!dptr->srcs)


params->use_getput should be 1 here, but it is 0, it becomes 1 later on.
The whole case distinction is made again in snd_pcm_route_convert1_many, 
removing it here solves my problem.

  ciao
    gd...

-- 
Gerhard Dirschl
Karlsruhe
Germany


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Re: Noise Problem

[Takashi Iwai]

At Wed, 14 May 2003 08:17:52 +0200,
Gerhard Dirschl wrote:
> 
>  Hi.
> 
> I've tried to record a few samples with my M-Audio Audiophile using the
> following settings:
(snipped)
> params->use_getput should be 1 here, but it is 0, it becomes 1 later on.
> The whole case distinction is made again in snd_pcm_route_convert1_many, 
> removing it here solves my problem.

thanks for pointing out!  i think it's one of the long-standing bugs.

fixed on cvs now.


ciao,

Takashi


-------------------------------------------------------
Enterprise Linux Forum Conference & Expo, June 4-6, 2003, Santa Clara
The only event dedicated to issues related to Linux enterprise solutions
www.enterpriselinuxforum.com