Re: [Alsa-user] Clicks with MP3 files

[andrew c. <an...@ac...>]

For the record, this seems to be caused by a USB hub.  I have no idea why
resampling fixes the issue, but a direct connection to the computer, at
44.1kHz, plays fine; clicks only appear when the hub is present.

Andrew


On Wed, Nov 14, 2012 at 08:52:58PM -0300, Andrew Cooke wrote:
> 
> Well, I have been reading about ALSA and asoundrc and the like, and it appears
> that one explanation for the lack of clicks with aplay is that it ends up
> being resampled to 48kHz (I do not know why, but this is from the aplay debug
> output).  And if I define a plug device that does the same then the mp3 also
> does not click.  Similarly, if I define a plug device that forces 44.1kHs then
> I get clicks for the wav file with aplay.
> 
> So my problem seems to be that I have clicks at 44.1kHz - the file format is
> irrelevant (which makes sense).
> 
> But still, I do not understand why.
> 
> Andrew
> 
> 
> On Wed, Nov 14, 2012 at 08:01:02PM -0300, Andrew Cooke wrote:
> > 
> > Hi,
> > 
> > I am an exprienced Linux user, but don't know much about ALSA, and I have a
> > strange problem that I do not know how to fix: 
> > 
> > When I play mp3s, either directly with mplayer2, or via the audacious music
> > player, targetting a USB sound card (AudioEngine D1) via ALSA, I hear clicks.
> > However, I do not hear clicks if I use a WAV file (generated from the MP3)
> > with aplay, or if I use audacious with Jack at 96kHz (which I think is a
> > clumsy way of making audacious upsample to 96kHz before targetting Jack which
> > in turn targets ALSA).
> > 
> > > aplay -l
> > **** List of PLAYBACK Hardware Devices ****
> > card 2: D1 [Audioengine D1], device 0: USB Audio [USB Audio]
> >   Subdevices: 1/1
> >   Subdevice #0: subdevice #0
> > card 3: VLink [Musical Fidelity V-Link], device 0: USB Audio [USB Audio]
> >   Subdevices: 1/1
> >   Subdevice #0: subdevice #0
> > card 4: D2 [Audioengine D2], device 0: USB Audio [USB Audio]
> >   Subdevices: 1/1
> >   Subdevice #0: subdevice #0
> > 
> > > mplayer2 -ao alsa:device=hw=2.0 test.mp3
> > [audible clicks]
> > 
> > > lame --decode test.mp3 test.wav
> > 
> > > aplay -D default:CARD=D1 -t wav test.wav 
> > Playing WAVE '/crypto/music/test.wav' : Signed 16 bit Little Endian, Rate
> > 44100 Hz, Mono
> > [works fine]
> > 
> > >  uname -a
> > Linux block 3.4.11-2.16-desktop #1 SMP PREEMPT Wed Sep 26 17:05:00 UTC 2012
> > (259fc87) x86_64 x86_64 x86_64 GNU/Linux
> > 
> > I am using OpenSuse 12.2 with their stock (desktop) kernel.  ALSA version
> > 1.0.25-3.5.1.
> > 
> > I have the same problem with the D2 (and the D1 was fine with OpenSuse 12.1).
> > The VLink is fine, but then it's a USB synch-to-asynch buffer, so maybe it
> > should work better.
> > 
> > I do not notice any strange values (CPU use, disk use) with atop when the
> > clicks happen - this is a lightly loaded, fairly powerful desktop.
> > 
> > Any advice?  I have no ALSA-specific configuration - the above is just what
> > happens by default.  I am using the KDE desktop, which means that phonon is
> > running, but I thought I was avoiding that by targetting ALSA directly (I am
> > not very impressed with phonon - it seems to get confused if devices are
> > unplugged etc and has also given clicks; I was thinking ALSA should be
> > simpler...)
> > 
> > Thanks,
> > Andrew
> > 
>