Re: Glitch-free presentations with Windows 7 and Matlab

[Trevor Agus <Trevor.Agus@xxxxxx>]

Ah yes, we have a solution for the Windows 7 volume-control problem. The code is
here: http://www.earcatching.com/volumecontrol/
It lets you control the two relevant Windows 7 sliders from a single line in
Matlab. For example
> tvolumecontrol(1,1); %sets both sliders to maximum.
Saying that, it turns out that our soundcard just ignores those volume controls
anyway.

Thanks for the links, Etienne. So a correction: others have managed to compile
playrec on Windows 7. I probably knew that once. However, I gave up after a
7-hour debugging marathon, which makes me think that, even if someone helps me
compile it successfully, playrec isn't going to the be the easily portable,
one-size-fits-all solution that used to exist.

Trevor

On 18 October 2011 19:46, Etienne Gaudrain <egaudrain.cam@xxxxxxxxx> wrote:
> Hi,
>
> Unless someone has found the solution (I can't recall), there's another
> issue with Windows 7 which is that the mixer interface is unbelievably
> complicated and it is a nightmare to set the sound level. If I'm correct
> that nobody has provided a solution to this problem as yet, this is another
> good reason to stick to good old XP.
>
> Note that the issue also sometime arise with ASIO drivers in WinXP as well
> because the ASIO volume isn't always linked to the Windows' mixer volume.
>
> Otherwise, another alternatives is to play sounds through TDT Systems. But
> again we are far from the simple "sound" function in Matlab (although I
> don't see why anyone would like to use this when the audioplayer object
> offers so much more flexibility).
>
> -Etienne
>
>
> PS: Trevor, I guess you've seen this:
> http://www.playrec.co.uk/forum/viewtopic.php?id=209 and other entries in
> this forum: http://www.playrec.co.uk/forum/viewforum.php?id=4.
>
>
>
> On 18/10/2011 16:52, Trevor Agus wrote:
>>
>> I've found it surprisingly difficult to present glitch-free sounds with
>> Windows 7.
>>
>> The short answer is that Padraig Kitterick's "asioWavPlay" seems to be the
>> simplest reliable method (remembering to buffer the waveforms with 256
>> samples
>> of silence to avoid truncation issues). For those with more complex needs,
>> perhaps soundmexpro or PsychToolbox would be better. I'd value any second
>> opinions and double-checking, so a review of the options follows, with all
>> the
>> gory details.
>>
>> I've been using a relatively old version of Matlab (R2007b) with a
>> Fireface UC
>> soundcard. If the problems are fixed in another version or soundcard, I'd
>> love
>> to know about it.
>>
>> ===Matlab's native functions (sound, wavplay, audioplayer)
>> Large, unpredictable truncations were the least of our problems. We also
>> often
>> got mid-sound glitches, ranging from sporadic (just a few subtle glitches
>> per
>> minute) to frequent (making the sound barely recognisable). The magic
>> formula
>> for eliminating the glitches seemed to be to keep the soundcard turned off
>> until
>> the desktop was ready, with all background programs loaded. (Restarting
>> either
>> the soundcard or  the computer alone guaranteed some glitches.) So this
>> formula
>> seems to work, but it's a bit too Harry Potter for my liking, and the
>> spell
>> might change with the next Windows update.  I think I read that Fireface
>> were
>> no longer supporting Microsoft's vagaries, and they recommended using
>> ASIO. I'm
>> not sure if other high-end soundcard manufacturers are any different.
>> Since
>> Matlab's native functions don't support ASIO (unless the new versions
>> do?),
>> I think we're forced to look at the ASIO options.
>>
>> ===playrec
>> This seems to be potentially the most flexible method of presenting sounds
>> but
>> I've hit a brick wall compiling it for Windows 7. I think its author
>> stopped
>> providing support for it a few years ago. Has anyone had more success than
>> me?
>>
>> ===asioWavPlay
>> This simply presents a .wav file using ASIO. It's a little annoying that
>> you
>> have to save your sound to disk before presenting it, but as Joachim
>> pointed
>> out, it's not too difficult to automate this process. While doing that, I
>> add
>> 256 samples of silence to the end to work around the truncation problem.
>>
>> ===pa_wavplay
>> This is nearly the perfect solution except (1) the number of samples
>> truncated
>> from the end is slightly unpredictable and (2) it prints a message on the
>> screen after every sound ("Playing on device 0"). For these two reasons, I
>> prefer asioWavPlay.
>>
>> ===soundmexpro
>> This might be best choice for the high-end user (I've just had a quick
>> look at
>> the demo version today). It's easy to install and there are good
>> tutorials, but
>> it involves initialising sound objects, etc. -- it's not just a
>> replacement for
>> Matlab's "sound" command. Also it looks like it's ?500+.
>>
>> ===PsychToolbox
>> Originally designed for visual experiments, PsychToolbox has now got quite
>> extensive low-latency sound functions, including realtime continuous
>> playing/recording. It's also free. However, it's slightly challenging to
>> install  Like soundmexpro, it's object-oriented -- so don't expect to play
>> a
>> sound with a simple one-liner.
>>
>> ===PortAudio
>> Most of above programs are based on this C library. If you're an
>> experienced
>> programmer, perhaps you'd prefer to go direct the source? And while you're
>> there, perhaps you could write the perfect Matlab-ASIO interfaces for the
>> rest
>> of us? (Please!)
>>
>> Has anyone found a simpler solution? I'd be glad to hear it.
>>
>> Trevor
>
>
> --
> Etienne Gaudrain, PhD
> MRC Cognition and Brain Sciences Unit
> 15 Chaucer Road
> Cambridge, CB2 7EF
> UK
> Phone: +44 1223 355 294, ext. 645
> Fax (unit): +44 1223 359 062
>