No support for 128kHz sample rate ?

No support for 128kHz sample rate ?

[Thomas Charbonnel]

Hi,

I'm currently working on the hdsp 9632 driver. This card supports sample
rates up to 192kHz, including 128kHz and 176.4kHz. The problem is 128kHz
sample rate seems to have been omited in <sound/pcm.h>. How am I supposed
to deal with this ?

Thomas





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Re: No support for 128kHz sample rate ?

[Takashi Iwai]

At Thu, 14 Aug 2003 17:19:01 +0200 (CEST),
Thomas Charbonnel wrote:
> 
> Hi,
> 
> I'm currently working on the hdsp 9632 driver. This card supports sample
> rates up to 192kHz, including 128kHz and 176.4kHz. The problem is 128kHz
> sample rate seems to have been omited in <sound/pcm.h>. How am I supposed
> to deal with this ?

there are two ways:

1. define a new bit for 128k, and add to your rates field.
   easy one but will affect others.

2. define your own hw_constraints.
   add something like the following:

	static unsigned int xxx_rates[] =
		{ 32000, 44100, ....., 128000, 176400, 192000 };
	static snd_pcm_hw_constraint_list_t xxx_hw_const_rates = {
		.count = ARRAY_SIZE(xxx_rates), 
		.list = xxx_rates,
	};

  and in the open callback of pcm:

	static int snd_xxx_pcm_open(snd_pcm_substream_t *substream)
	{
		....

		snd_pcm_hw_constraint_list(substream->runtime, 0,
					   SNDRV_PCM_HW_PARAM_RATE,
					   &xxx_hw_const_rates);
		....
	}

  then add SNDRV_PCM_RATE_KNOT to rates field, which indicates the
  unconventional rates are supported.



well, i would take the latter :)

ciao,

Takashi


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Re: No support for 128kHz sample rate ?

[Thomas Charbonnel]

> At Thu, 14 Aug 2003 17:19:01 +0200 (CEST),
> Thomas Charbonnel wrote:
>>
>> Hi,
>>
>> I'm currently working on the hdsp 9632 driver. This card supports
>> sample rates up to 192kHz, including 128kHz and 176.4kHz. The problem
>> is 128kHz sample rate seems to have been omited in <sound/pcm.h>. How
>> am I supposed to deal with this ?
>
> there are two ways:
>
> 1. define a new bit for 128k, and add to your rates field.
>    easy one but will affect others.
>
> 2. define your own hw_constraints.
>    add something like the following:
>
> 	static unsigned int xxx_rates[] =
> 		{ 32000, 44100, ....., 128000, 176400, 192000 };
> 	static snd_pcm_hw_constraint_list_t xxx_hw_const_rates = {
> 		.count = ARRAY_SIZE(xxx_rates),
> 		.list = xxx_rates,
> 	};
>
>   and in the open callback of pcm:
>
> 	static int snd_xxx_pcm_open(snd_pcm_substream_t *substream)
> 	{
> 		....
>
> 		snd_pcm_hw_constraint_list(substream->runtime, 0,
> 					   SNDRV_PCM_HW_PARAM_RATE,
> 					   &xxx_hw_const_rates);
> 		....
> 	}
>
>   then add SNDRV_PCM_RATE_KNOT to rates field, which indicates the
> unconventional rates are supported.
>
>
>
> well, i would take the latter :)
>
>

Thanks,
I reported this because I thought 128kHz was somehow conventional, but I'm
ok with the hw_constraints method.

Thomas





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