[android-developers] Re: Low level audio really needed - too much latency in SoundPool, AudioTrack for more real time stuff

Hi Niko,
thank you for responsing.
But I don't think, that the reason for the latency-problems is the
linux-OS.
There are audio-applications without such latency-problems, e.g. have
a look at:
LMMS - Linux Multimedia Studio, URL:
http://lmms.sourceforge.net/

But I am wondering, that there is no feedback here in the list to my
above message, though the audio-performances are a basic necessity!

Greetings
Ulrich

On 26 Okt., 12:38, niko20 <nikolatesl...@yahoo.com> wrote:
> Hi Ulrich,
>
> Interesting that our timing tests work out to similar values!
>
> Anyway audio has really always seemed to be a problem with Linux,
> which android is based on...
>
> just hope someday we will actually get some fast audio low level
> access. I'd like to write some real music apps. But it's not possible
> right now (like a real keyboard synth) - I mean, it's possible, but
> the response time won't be so great and users will definitely
> complain. Of course without multitouch it's probably moot anyway, they
> would just complain about that :P
>
> I don't see how android can really be a "competitor" to iphone like
> everyone seems to think (I don't think that anymore at least, but it's
> a good alternative) since audio wise it's got pretty bad performance.
>
> -niko
>
> On Oct 26, 5:56 am, Ulrich Althöfer <ulrich.althoe...@web.de> wrote:
>
> > On 26 Okt., 09:17, niko20 <nikolatesl...@yahoo.com> wrote:
>
> > > Ok I first have to say that I'm biased, 'cus I like to write music
> > > apps (like music generation apps). However, this affects games as
> > > well.
>
> > > It's somewhat disappointing how OpenGL has made it into the NDK now
> > > but there isn't any NDK methods to get to sound to have faster access.
> > > Over the weekend I did some more testing and if you make a "drum" app,
> > > for example, and play the sound using either SoundPool or AudioTrack,
> > > you will get about a 100ms delay buffer, which is clearly audible
> > > (gap).
>
> > > I made  a test app where when you touch the screen, upon the DOWN
> > > event, it would play a short sound (like a drum sound). It clearly was
> > > not real time responsive or even close - you could hear the delay.
>
> > > I'd be interested to know if anyone who has made a game has any
> > > trouble with sounds? It seems like they aren't going to really trigger
> > > real time enough if you use SoundPool, for example. Am I completely
> > > wrong? Seems like your game is going to perform an action, play a
> > > sound, but the sound will have latency which I would think would throw
> > > off the game a bit.
>
> > > I tested to see if it perhaps was just the touch event itself that was
> > > slow - I added code to change the background color of the app when you
> > > touch down, and then change it back when you let up. The color changed
> > > almost instantaneously. So it's not the event handling, but rather,
> > > the sound objects that have the delay issues.
>
> > > I found that if I used AudioTrack (I tried it in streaming mode so I
> > > had more control over buffer size), it wouldn't allow me to create the
> > > object unless the buffer was at least 2048 samples in size (for the
> > > format I was using whic was I think 22050 mono 16 bit - this would
> > > work out to almost 100ms buffer before the track begins to play), and
> > > strangely I found that the amount of buffer must have been the same
> > > for SoundPool since when loaded with the same sound, the delay was
> > > similar. I also tried AudioTrack in static mode and it still had the
> > > same delay as SoundPool, or using AudioTrack in stream mode too!
>
> > > To get really good audio response we need to get down to the 30ms
> > > delay range or so (obviously the faster the better), the iphone does
> > > this with it's AudioUnit objects (of course they are in native code,
> > > which you write in C).
>
> > > I just hope that by the time we get to Flan, we may have NDK audio
> > > access, and hopefully we can get more direct audio streams for some
> > > real processing power.
>
> > > Hasn't this affected games much? I would think it would still be a
> > > problem in games even now, with latency so high. Even though the docs
> > > say SoundPool and static AudioTrack will have lowest latency possible,
> > > it still seems high to me.
>
> > > -niko
>
> > Yes, I confirm your experiences.
> > Have a look at the entry:
> > "SoundPool: playing/stopping-delaytime sometimes greater 300 ms"http://groups.google.com/group/android-developers/browse_thread/threa...
> > Greetings
> > Ulrich
>
>
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