Thanks Kevin. I have another question. Can I produce sound or tone inside my JAVA code instead of reading a sound file from somewhere when the user touches a point on the screen? This way I just have to "emit" a sound at some frequency/pitch (defined numerical value), based on a touch event.
On Jan 21, 4:02 pm, Kevin Duffey <andjar...@gmail.com> wrote: > Well firstly, let me stress that music apps generally require a little bit > more than basic java knowledge, and more so, basic android knowledge. Aside > from that, Android presently is difficult at best for real-time touch/play > sounds sort of apps. I've got a project started to make a MPC like app, but > have been reading that presently the ability to make low-latency music apps > is pretty much impossible for a few reasons. The main one being, the latency > between touch events and actually firing sounds quickly is a killer. Beyond > that, most apps that utilize any sort of say effects like delay, echo, and > play multiple sounds simultaneously are going to require the NDK for its > much faster performance. The problem is, let's say you load up 5 samples > into 5 buttons. The user presses one, you open the Android sound mechanism > and play that sound. Great..it works. There are lots of apps (Chuck Norris > comes to mind on Market) that offer buttons that you press and play some > sound bit. If you start pressing these buttons rapidly tho things start to > fall apart. But if you do use the NDK to "mix" the various audio sounds into > one mxied audio bytestream to play back, the problem there is the JNI > overhead of sending the various java loaded sound byte streams to mix thru > JNI to the NDK, then it mixes really fast, but the NDK doesn't have access > to the sound hardware.. so now that mixed byte stream has to come back thru > JNI to Java to be played. Hence, the double latency issue presently. This > also bites high framerate video games.. the same sort of issue with sending > bitmap images to the NDK layer to do fancy things or construct a frame, > requires (at least if I've read correctly) coming back thru JNI to put the > image on the screen. OpenGL is implemented (1.0 I think) for Java on > android, so you can get fairly decent graphics going.. and as I understand > it the Java implemention uses JNI calls to the OpenGL layer too. > > There are a couple things coming hopefully soon to Android. The first bieng > OpenCL to allow better hardware access to sound streams. I don't know the > details of it yet, but I think it's the same API used on iPhone for low > latency audio playback. AS well, I think OpenGL 1.1 or something like it is > coming soon. The main thing is, both of these I think..again..not for sure.. > give the NDK direct access to the audio and video buffers so that you can > use NDK code to mix audio and play it directly, as well as do video things > like redraw a frame, then blit it to the screen. I am not for sure on this.. > hopefully someone can give a better idea of this. > > On Tue, Jan 19, 2010 at 8:05 AM, Jack <jackzo...@gmail.com> wrote: > > Hi, I am thinking of developing a simple Android application that lets > > users compose music on Android phones. > > > I am new to the Android platform. I have some coding experience in > > Java that involves being aware of basic OOPS and Java concepts and > > developing some small Java applications(less than 1k lines of code). I > > have set up Android on my Linux system and have been able to run a > > "hello World" application. > > > I want to develop a simple Android app in a month wherein users can > > compose music. What I want to do is this- A touch on the screen > > should produce/emit a sound/tone. Touching different parts of the > > screen should produce/emit sounds of different pitch levels/ > > frequencies. Once this is done I want to improve the UI and add some > > basic features of playback, "clearing" currently selected tones on the > > screen. > > > How do I start doing this? Also, given my limited experience with > > java, how should I divide the tasks so that I can finish this in a > > month? > > > -- > > You received this message because you are subscribed to the Google > > Groups "Android Beginners" group. > > > NEW! Try asking and tagging your question on Stack Overflow at > >http://stackoverflow.com/questions/tagged/android > > > To unsubscribe from this group, send email to > > android-beginners+unsubscr...@googlegroups.com<android-beginners%2bunsubscr...@googlegroups.com> > > For more options, visit this group at > >http://groups.google.com/group/android-beginners?hl=en -- You received this message because you are subscribed to the Google Groups "Android Beginners" group. NEW! Try asking and tagging your question on Stack Overflow at http://stackoverflow.com/questions/tagged/android To unsubscribe from this group, send email to android-beginners+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-beginners?hl=en
