Is there any other samples Ripple mesh deformation using unity3d or iPhone variant.Sorry for asking like this.At this time i am looking same Water ripple effects using Unity 3d or iPhone[But above mentioned project is Mac version].If anybody having any samples or ideas please reply….

Thanks in Advance,

in the not so distant past I would probably just tell you to totally avoid any sort of software decompression on the iphone since doing that generally totally screws your performance. However, with the advent of the iPhone 4, we now have three very popular devices (ie 3gs,iPad,iphone4) that are probably more than capable of doing some real-time software decompression.

As for how you implement it: it is exactly like doing it for uncompressed, only you have to uncompress the mp3 before playing :-) Now decompressing mp3s(or aacs) is kinda a pain in the ass, you need to find a decent open source decompression lib, (or go with OGG/libogg/libvorbis they are fairly decent) and, if you are streaming then you need to decompress the file in small buffer-sized chunks, making the decompression that much more complicated….

you know what, I still stand by my original thought: just dont do it. (or just go get FMOD and forget OpenAL)

If you need to play long music files (which will generally be mp3 or aac or some other compressed format) then just play those through the hardware decompressor via the AudioToolkit.

What I generally do is break my sounds up into two categories: sounds that will be pretty small when uncompressed and sounds that will be fooking gargantuan when uncompressed. The latter category gets converted to mp3 or mp4 and played back via audio toolkit, the uncompressed ones get played back via OpenAL. (cuz OpenAL is soooo much more responsive)

If you absolutely must have streaming mp3s and you absolutely must have access to the buffer data for some reason, then you are stuck doing the long yards to implement a proper software decompression system. (but I am lazy and would never do that, i would either change my requirements or get FMOD)

Cheers!
-B

Thank you for this very useful report on OpenAL streaming ;)

You use for your example uncompressed format but can you tell me if it is possible to use OpenAL streaming with compressed format like mp3 or aac in simply way ?

Thanks,

Phetsana.

I guess it depends on what kinds of filters you want. There are not many built-in AUs on the iphone and if you already know how to do the DSP enough to write your own AU, then you might as well just do it in OpenAL, it is much the same. If the AU you want is already available, then it is may be worth the effort to just go to CoreAudio.

Cheers!
-B

I’ve seen a lot of stuff around about using Audio Units for DSP. I’m not really interested in re-writing my sound engine to lower level code just to get a filter – but the filter is vital to my app.

Do you think I’m better off re-writing the sound engine to use Audio Units (major pain) or just attempting to filter using OpenAl/buffers?

Thanks – Goat

with OpenAl you are pretty much on your own as far as filtering goes. You have to do all the bit twiddling yourself.
With the streaming buffers your best bet is to apply the filters as you load in the buffers (ie load a buffer, run your filter algo on it, queue it up, rinse repeat.) Many DSP filters rely on a window of data, so you may need to keep the previous and post buffers around just for data continuity etc..

if your filters are changing in near real time, then you will want to make your buffer size smaller so that you can be more responsive to the filter changes. (but if you make them really small, then you may underrun, so you might need more buffers etc.. )

Good luck!

Cheers!
-B

I actually stopped being lazy and did exactly as you suggested and got everything running as I wanted. Thanks for your excellent tutorials.

My next problem is applying some basic DSP (filters etc) to the stream. Do you have any pointers on that?

Thanks again!