All my audio render callbacks use the C-function-pointer-to-call-named-selector trick in JambaLaya. (http://audiofreakshow.com)
In fact, the entire app is written in Objective-C. Between SnoizeMIDI, MTCoreAudio, and my own private TBAudioUnits framework - I deal with C or C++ almost never. In fact, SnoizeMIDI (http://snoize.com/) is a great example of something that most people would think would be too slow. It takes the high performance data structures like MIDIMessageList variable length structs, then converts them into NSArray's of Objective-C objects (one per message), then dispatches them through a chain of Objective-C implemented filters using polymorphism. I end up stashing them in a set of NSArray implemented queues (protected by NSLock) from which they are pulled during that "probably too slow" Objective-C implemented render callback -then dispatched to the audio units, and then released. Very low latency, feels like hardware, and all Objective-C. There is no good reason not to have the base classes for AudioUnit be in Objective-C rather than C++ other than the personal biases of certain CoreAudio team members. I can't fault them, they use what they know and they do a great job, but their way isn't the only one and a nice Objective C wrapper for the whole thing that hides the C++ is both doable and a long standing feature request. On Feb 28, 2010, at 7:46 PM, Kyle Sluder wrote: > On Sun, Feb 28, 2010 at 7:24 PM, Erik Buck <erik.b...@sbcglobal.net> wrote: >> I disagree. I have written very low latency device drivers in Objective-C. >> Why do you think Objective-C has too much "latency" for audio? When >> properly used, Objective-C programs are no more likely to be preempted than >> any other kind of program. Message dispatch generally has constant time and >> is only 2.5 times the cost of a C function call. There aren't many function >> calls or messages sent in audio processing anyway. Signal processing >> routines tend to be long loops. Objective-C _IS_ C which means it is likely >> usable in any situation where C is usable. > > I am simply relaying the wisdom I received from the CoreAudio folks > over on coreaudio-api. Frequently people ask about using ObjC in their > render callbacks, and the engineers are quick to put the kibosh on > that idea. > > --Kyle Sluder > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/eagleoffshore%40mac.com > > This email sent to eagleoffsh...@mac.com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
