Very interesting.. but from what you've said, you're running into the same latency issues as everyone else on android. The chance of making a multi-touch MPC program, or a synth that can play multiple sounds at once seems a bit far off yet for Android at this point. :(
On Mon, Apr 12, 2010 at 1:28 PM, Mario Zechner <[email protected]>wrote: > I did some audio work on Android and have to agree with Kevin's > analysis. Writting to the audio device via AudioTrack works and you > can also alter the buffer sizes to get to the lowest possible latency > but from what i remember the buffer was still pretty big. Also, > AudioTrack does not allow passing in direct buffers so you have to do > everything with an array backed buffer if you go native which might > incurr overhead as the array has to be locked when working with it in > native code. > > And i know it's considered spam and off topic, but Kevin maybe the lib > i'm working at the moment is of interest for you. It does have some > features of XNA (cross-plattform, meaning Windows/Linux/Mac and > Android) and even has more or less ports of some XNA classes like > SpriteBatch) and is pretty big already, covering a lot of ground. You > can check it out at http://www.badlogicgames.com and > http://code.google.com/p/libgdx/. > The public API is heavily document and there's a lot of examples in > the SVN that should get you started. Alternatively there's a series of > articles that serve as a tutorial. This series is not yet finished but > gets updated on a constant basis. Sorry for the thread hijack :) > > On 12 Apr., 22:10, Kevin Duffey <[email protected]> wrote: > > Mixing audio in itself is not too hard.. you basically add each byte of > each > > sound (that plays at the same exact point in time). You do face the issue > of > > dynamic range.. if you are mixing 16-bit sounds, you don't want to use a > > 16-bit value to store the mixed sounds.. you'll overflow it. or clip the > > sound. Usually you'll use a 32-bit integer to add all the sounds, then > > you'll lower it to 24-bit or 16-bit with some fancy algorithm that won't > > clip all the mixed sounds.. sort of like lowering their combined volumes > so > > they don't clip. However, you can't keep lowering volumes with more > sounds.. > > it changes the overall mixed volume.. there is some FFT or something like > > that which properly does this. It's been a long time since I did this > stuff, > > back when SoundBlaster 8-bit sound card was out and mikmod and module > > players were quite popular. Long before the sound cards mixed audio > > themselves. ;) > > > > I am sure you can find stuff on it. I too wanted to work on a low-latency > > music app, but until google puts more resources into making the NDK and > > android platform on par with iPhone, I don't think it's worth the effort. > > There is just WAY too many problems with the issue of low latency audio > > right now. Really what you need is to use the NDK, pass the sound buffers > of > > different sounds (or better yet, NDK can directly access the buffers of > > loaded sounds or SD stored sounds), do the mixing there, and then be able > to > > play to a the sound output in some low latency manner. Unless things have > > changed, I've been led to believe we're a long ways off before we'll have > > anything like that. > > > > Sadly, it seems google/android team is completely quiet on any details at > > all with regards to this stuff. I've not been able to find one bit of > info > > whether or not they are hearing us game/audio developers and are working > on > > a better platform for us or not. Given their stagnant market work and > lack > > of any info at all on anything being worked on.. I wouldn't count on > > anything anytime soon. Let's hope I am very wrong on this, but I fear > that > > the articles that indicate android will surpass iphone by 2012 are > grossly > > misleading if android as a platform can't compete on games and audio with > > iPhone. :( They still need to fix the multi-touch issue which plagues > gamers > > on several devices but apparently it's in the hardware, not the platform. > > > > If I am wrong.. if there is some place google posts what is coming and > > when.. please correct me. I really love the idea of Android, and still > > follow along, but I've basically stopped any development primarily > because > > there isn't much money in it, and with no idea if far better game/audio > > support is coming, I don't want to waste time hoping. There are other > > avenues of interest in non game/music related things for Android tho, but > my > > heart lies in making a kick ass music app... and possibly a side scroller > > game at some point. Would be wonderful if Google had something like XNA > for > > us. :) > > > > On Mon, Apr 12, 2010 at 12:42 PM, k_day <[email protected]> wrote: > > > Despite everything I have read about the difficulty of making low > > > latency audio apps in Android, I am giving it a shot. To start, I > > > loaded each note in an octave into a SoundPool, and then looped > > > through each note that was to be played on that beat and called > > > play(). This didn't even come close to being accurate enough for me, > > > and got especially bad if a lot of notes were being played at once. > > > > > From what I read, the only way to do something like this is to mix the > > > audio yourself, though I am not entirely sure how to go about this. > > > My initial thought is that for each beat, I could precompute the sound > > > the sound that is to be played (i.e., combine the wav's), and then > > > pass that stream to an AudioTrack when it is time to be played. > > > > > Are there any good examples out there for how to mix audio like this, > > > or libraries I could use to do this for me? How have coders of other > > > music apps dealt with this? > > > > > -- > > > You received this message because you are subscribed to the Google > > > Groups "Android Developers" group. > > > To post to this group, send email to > [email protected] > > > To unsubscribe from this group, send email to > > > [email protected]<android-developers%[email protected]> > <android-developers%[email protected]<android-developers%[email protected]> > > > > > For more options, visit this group at > > >http://groups.google.com/group/android-developers?hl=en > > > > > To unsubscribe, reply using "remove me" as the subject. > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected]<android-developers%[email protected]> > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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