Re: [alsa-devel] USB transfer_buffer allocations on 64bit systems

[Daniel Mack <daniel@caiaq.de>]

On Thu, May 13, 2010 at 12:50:48AM +0100, Pedro Ribeiro wrote:
> On 11 May 2010 18:38, Daniel Mack <daniel@caiaq.de> wrote:
> > On Tue, May 11, 2010 at 06:32:50PM +0100, Pedro Ribeiro wrote:
> >> On 11 May 2010 18:10, Daniel Mack <daniel@caiaq.de> wrote:
> >> > No surprise here. The 4 channels are mux'ed in an interleaved fashion,
> >> > so if the buffers contain rubbish, you will hear artefacts on all
> >> > channels.
> >>
> >> So what would be the testcase you would like me to try?
> >
> > Would be good to see what happens if you could record audio (with
> > arecord would be sufficient), just to see whether the same problem
> > exists in the other direction.
> >
> > Either record an externally generated sine tone and open the resulting
> > wave file in an editor. With the amount of artefacts you describe, they
> > should easily be visible.
> 
> Ok let me see if I got this straight:
> 
> I should record some sound with the audio card and see if it impacts
> the recording? May take me a few days, I need to get a microphone or
> something like that borrowed.

Yes, exactly.

> > Another option is to play back any kind of recorded audio thru an audio
> > device that does not show the problem (some internal, onboard device?).
> >
> 
> What do you mean by this? I didn't get it. I usually use my onboard
> intel HDA for listening to music and have no problems.

I was just thinking of a way to judge whether the recording is affected.
And probably the best way is to listen to it :)

Daniel