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From: Uwaysi Bin Kareem <uwaysi.bin.kareem@paradoxuncreated.com>
To: linux-kernel@vger.kernel.org, clemens@ladisch.de
Subject: Re: Possible bug, with extreme low latency audio.
Date: Wed, 02 Mar 2011 21:01:11 +0100	[thread overview]
Message-ID: <op.vrqe79rh6426ze@millennium> (raw)
In-Reply-To: <4D6DF1B2.2010500@ladisch.de>

On Wed, 02 Mar 2011 08:28:50 +0100, Clemens Ladisch <clemens@ladisch.de>
wrote:

> Uwaysi Bin Kareem wrote:
>> The other is a firewire device (Konnekt24d using FFADO, running on the  
>> old
>> firewire stack).
>> The firewire device actually plays nicely without much buffer underruns
>> down to 0.363 ms latency (8x2 @ 44.1k).
>
> FireWire packets are sent every 125 µs; for audio, every packet contains
> either zero or eight samples, and the proportion of data and no-data
> packets is adjusted so that the overall rate is 44100 samples per
> second.  So 8x2 is the theoretical minimum.
>
>> However it seems to choke at 8x2 @ 96k.
>
> At sample rates above 48 kHz, there are 16 samples per packet (and above
> 96 kHz, 32).  It is not possible to use 8x2 at 96 kHz, and FFADO should
> not have allowed you to try it; please file a bug there:
> <http://subversion.ffado.org/report> (requires a login).
>
Ok, I am hitting the hardware limits. I'll inform FFADO crew about this.  
There are probably more bound to hit this limit, as lowlatency operation  
with Linux, is getting this good. A good error msg with the above  
information, would be good.

Best Regards,
Uwaysi.


  reply	other threads:[~2011-03-02 20:01 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-01  0:58 Possible bug, with extreme low latency audio Uwaysi Bin Kareem
2011-03-01 10:57 ` Clemens Ladisch
2011-03-01 16:59   ` Uwaysi Bin Kareem
2011-03-02  7:28     ` Clemens Ladisch
2011-03-02 20:01       ` Uwaysi Bin Kareem [this message]
2011-03-03 19:07   ` Uwaysi Bin Kareem
2011-03-04  3:36   ` Renicing for OpenGL smoothness Uwaysi Bin Kareem

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