1 //! This module is an attempt to provide a friendly, rust-esque interface to Apple's Audio Unit API.
2 //!
3 //! Learn more about the Audio Unit API [here](https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40003278-CH1-SW2)
4 //! and [here](https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/TheAudioUnit/TheAudioUnit.html).
5 //!
6 //! TODO: The following are `kAudioUnitSubType`s (along with their const u32) generated by
7 //! rust-bindgen that we could not find any documentation on:
8 //!
9 //! - MIDISynth = 1836284270,
10 //! - RoundTripAAC = 1918984547,
11 //! - SpatialMixer = 862217581,
12 //! - SphericalHeadPanner = 1936746610,
13 //! - VectorPanner = 1986158963,
14 //! - SoundFieldPanner = 1634558569,
15 //! - HRTFPanner = 1752331366,
16 //! - NetReceive = 1852990326,
17 //!
18 //! If you can find documentation on these, please feel free to submit an issue or PR with the
19 //! fixes!
20
21
22 use error::Error;
23 use std::mem;
24 use std::ptr;
25 use std::os::raw::{c_uint, c_void};
26 use sys;
27
28 pub use self::audio_format::AudioFormat;
29 pub use self::sample_format::{SampleFormat, Sample};
30 pub use self::stream_format::StreamFormat;
31 pub use self::types::{
32 Type,
33 EffectType,
34 FormatConverterType,
35 GeneratorType,
36 IOType,
37 MixerType,
38 MusicDeviceType,
39 };
40
41
42 pub mod audio_format;
43 pub mod render_callback;
44 pub mod sample_format;
45 pub mod stream_format;
46 pub mod types;
47
48
49 /// The input and output **Scope**s.
50 ///
51 /// More info [here](https://developer.apple.com/library/ios/documentation/AudioUnit/Reference/AudioUnitPropertiesReference/index.html#//apple_ref/doc/constant_group/Audio_Unit_Scopes)
52 /// and [here](https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/TheAudioUnit/TheAudioUnit.html).
53 #[derive(Copy, Clone, Debug)]
54 pub enum Scope {
55 Global = 0,
56 Input = 1,
57 Output = 2,
58 Group = 3,
59 Part = 4,
60 Note = 5,
61 Layer = 6,
62 LayerItem = 7,
63 }
64
65 /// Represents the **Input** and **Output** **Element**s.
66 ///
67 /// These are used when specifying which **Element** we're setting the properties of.
68 #[derive(Copy, Clone, Debug)]
69 pub enum Element {
70 Output = 0,
71 Input = 1,
72 }
73
74
75 /// A rust representation of the sys::AudioUnit, including a pointer to the current rendering callback.
76 ///
77 /// Find the original Audio Unit Programming Guide [here](https://developer.apple.com/library/mac/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/TheAudioUnit/TheAudioUnit.html).
78 pub struct AudioUnit {
79 instance: sys::AudioUnit,
80 maybe_render_callback: Option<*mut render_callback::InputProcFnWrapper>,
81 maybe_input_callback: Option<InputCallback>,
82 }
83
84 struct InputCallback {
85 // The audio buffer list to which input data is rendered.
86 buffer_list: *mut sys::AudioBufferList,
87 callback: *mut render_callback::InputProcFnWrapper,
88 }
89
90
91 macro_rules! try_os_status {
92 ($expr:expr) => (Error::from_os_status($expr)?)
93 }
94
95
96 impl AudioUnit {
97
98 /// Construct a new AudioUnit with any type that may be automatically converted into
99 /// [**Type**](./enum.Type).
100 ///
101 /// Here is a list of compatible types:
102 ///
103 /// - [**Type**](./types/enum.Type)
104 /// - [**IOType**](./types/enum.IOType)
105 /// - [**MusicDeviceType**](./types/enum.MusicDeviceType)
106 /// - [**GeneratorType**](./types/enum.GeneratorType)
107 /// - [**FormatConverterType**](./types/enum.FormatConverterType)
108 /// - [**EffectType**](./types/enum.EffectType)
109 /// - [**MixerType**](./types/enum.MixerType)
110 ///
111 /// To construct the **AudioUnit** with some component flags, see
112 /// [**AudioUnit::new_with_flags**](./struct.AudioUnit#method.new_with_flags).
113 ///
114 /// Note: the `AudioUnit` is constructed with the `kAudioUnitManufacturer_Apple` Manufacturer
115 /// Identifier, as this is the only Audio Unit Manufacturer Identifier documented by Apple in
116 /// the AudioUnit reference (see [here](https://developer.apple.com/library/prerelease/mac/documentation/AudioUnit/Reference/AUComponentServicesReference/index.html#//apple_ref/doc/constant_group/Audio_Unit_Manufacturer_Identifier)).
new<T>(ty: T) -> Result<AudioUnit, Error> where T: Into<Type>,117 pub fn new<T>(ty: T) -> Result<AudioUnit, Error>
118 where T: Into<Type>,
119 {
120 AudioUnit::new_with_flags(ty, 0, 0)
121 }
122
123 /// The same as [**AudioUnit::new**](./struct.AudioUnit#method.new) but with the given
124 /// component flags and mask.
new_with_flags<T>(ty: T, flags: u32, mask: u32) -> Result<AudioUnit, Error> where T: Into<Type>,125 pub fn new_with_flags<T>(ty: T, flags: u32, mask: u32) -> Result<AudioUnit, Error>
126 where T: Into<Type>,
127 {
128 const MANUFACTURER_IDENTIFIER: u32 = sys::kAudioUnitManufacturer_Apple;
129 let au_type: Type = ty.into();
130 let sub_type_u32 = match au_type.to_subtype_u32() {
131 Some(u) => u,
132 None => return Err(Error::NoKnownSubtype),
133 };
134
135 // A description of the audio unit we desire.
136 let desc = sys::AudioComponentDescription {
137 componentType: au_type.to_u32() as c_uint,
138 componentSubType: sub_type_u32 as c_uint,
139 componentManufacturer: MANUFACTURER_IDENTIFIER,
140 componentFlags: flags,
141 componentFlagsMask: mask,
142 };
143
144 unsafe {
145 // Find the default audio unit for the description.
146 //
147 // From the "Audio Unit Hosting Guide for iOS":
148 //
149 // Passing NULL to the first parameter of AudioComponentFindNext tells this function to
150 // find the first system audio unit matching the description, using a system-defined
151 // ordering. If you instead pass a previously found audio unit reference in this
152 // parameter, the function locates the next audio unit matching the description.
153 let component = sys::AudioComponentFindNext(ptr::null_mut(), &desc as *const _);
154 if component.is_null() {
155 return Err(Error::NoMatchingDefaultAudioUnitFound);
156 }
157
158 // Create an instance of the default audio unit using the component.
159 let mut instance_uninit = mem::MaybeUninit::<sys::AudioUnit>::uninit();
160 try_os_status!(
161 sys::AudioComponentInstanceNew(component, instance_uninit.as_mut_ptr() as *mut sys::AudioUnit)
162 );
163 let instance: sys::AudioUnit = instance_uninit.assume_init();
164
165 // Initialise the audio unit!
166 try_os_status!(sys::AudioUnitInitialize(instance));
167 Ok(AudioUnit {
168 instance: instance,
169 maybe_render_callback: None,
170 maybe_input_callback: None,
171 })
172 }
173 }
174
175 /// On successful initialization, the audio formats for input and output are valid
176 /// and the audio unit is ready to render. During initialization, an audio unit
177 /// allocates memory according to the maximum number of audio frames it can produce
178 /// in response to a single render call.
179 ///
180 /// Usually, the state of an audio unit (such as its I/O formats and memory allocations)
181 /// cannot be changed while an audio unit is initialized.
initialize(&mut self) -> Result<(), Error>182 pub fn initialize(&mut self) -> Result<(), Error> {
183 unsafe { try_os_status!(sys::AudioUnitInitialize(self.instance)); }
184 Ok(())
185 }
186
187 /// Before you change an initialize audio unit’s processing characteristics,
188 /// such as its input or output audio data format or its sample rate, you must
189 /// first uninitialize it. Calling this function deallocates the audio unit’s resources.
190 ///
191 /// After calling this function, you can reconfigure the audio unit and then call
192 /// AudioUnitInitialize to reinitialize it.
uninitialize(&mut self) -> Result<(), Error>193 pub fn uninitialize(&mut self) -> Result<(), Error> {
194 unsafe { try_os_status!(sys::AudioUnitUninitialize(self.instance)); }
195 Ok(())
196 }
197
198 /// Sets the value for some property of the **AudioUnit**.
199 ///
200 /// To clear an audio unit property value, set the data paramater with `None::<()>`.
201 ///
202 /// Clearing properties only works for those properties that do not have a default value.
203 ///
204 /// For more on "properties" see [the reference](https://developer.apple.com/library/ios/documentation/AudioUnit/Reference/AudioUnitPropertiesReference/index.html#//apple_ref/doc/uid/TP40007288).
205 ///
206 /// **Available** in iOS 2.0 and later.
207 ///
208 /// Parameters
209 /// ----------
210 ///
211 /// - **id**: The identifier of the property.
212 /// - **scope**: The audio unit scope for the property.
213 /// - **elem**: The audio unit element for the property.
214 /// - **maybe_data**: The value that you want to apply to the property.
set_property<T>(&mut self, id: u32, scope: Scope, elem: Element, maybe_data: Option<&T>) -> Result<(), Error>215 pub fn set_property<T>(&mut self, id: u32, scope: Scope, elem: Element, maybe_data: Option<&T>)
216 -> Result<(), Error>
217 {
218 set_property(self.instance, id, scope, elem, maybe_data)
219 }
220
221 /// Gets the value of an **AudioUnit** property.
222 ///
223 /// **Available** in iOS 2.0 and later.
224 ///
225 /// Parameters
226 /// ----------
227 ///
228 /// - **id**: The identifier of the property.
229 /// - **scope**: The audio unit scope for the property.
230 /// - **elem**: The audio unit element for the property.
get_property<T>(&self, id: u32, scope: Scope, elem: Element) -> Result<T, Error>231 pub fn get_property<T>(&self, id: u32, scope: Scope, elem: Element) -> Result<T, Error> {
232 get_property(self.instance, id, scope, elem)
233 }
234
235 /// Starts an I/O **AudioUnit**, which in turn starts the audio unit processing graph that it is
236 /// connected to.
237 ///
238 /// **Available** in OS X v10.0 and later.
start(&mut self) -> Result<(), Error>239 pub fn start(&mut self) -> Result<(), Error> {
240 unsafe { try_os_status!(sys::AudioOutputUnitStart(self.instance)); }
241 Ok(())
242 }
243
244 /// Stops an I/O **AudioUnit**, which in turn stops the audio unit processing graph that it is
245 /// connected to.
246 ///
247 /// **Available** in OS X v10.0 and later.
stop(&mut self) -> Result<(), Error>248 pub fn stop(&mut self) -> Result<(), Error> {
249 unsafe { try_os_status!(sys::AudioOutputUnitStop(self.instance)); }
250 Ok(())
251 }
252
253 /// Set the **AudioUnit**'s sample rate.
254 ///
255 /// **Available** in iOS 2.0 and later.
set_sample_rate(&mut self, sample_rate: f64) -> Result<(), Error>256 pub fn set_sample_rate(&mut self, sample_rate: f64) -> Result<(), Error> {
257 let id = sys::kAudioUnitProperty_SampleRate;
258 self.set_property(id, Scope::Input, Element::Output, Some(&sample_rate))
259 }
260
261 /// Get the **AudioUnit**'s sample rate.
sample_rate(&self) -> Result<f64, Error>262 pub fn sample_rate(&self) -> Result<f64, Error> {
263 let id = sys::kAudioUnitProperty_SampleRate;
264 self.get_property(id, Scope::Input, Element::Output)
265 }
266
267 /// Sets the current **StreamFormat** for the AudioUnit.
268 ///
269 /// Core Audio uses slightly different defaults depending on the platform.
270 ///
271 /// From the Core Audio Overview:
272 ///
273 /// > The canonical formats in Core Audio are as follows:
274 /// >
275 /// > - iOS input and output: Linear PCM with 16-bit integer samples.
276 /// > - iOS audio units and other audio processing: Noninterleaved linear PCM with 8.24-bit
277 /// fixed-point samples
278 /// > - Mac input and output: Linear PCM with 32-bit floating point samples.
279 /// > - Mac audio units and other audio processing: Noninterleaved linear PCM with 32-bit
280 /// floating-point
set_stream_format( &mut self, stream_format: StreamFormat, scope: Scope, ) -> Result<(), Error>281 pub fn set_stream_format(
282 &mut self,
283 stream_format: StreamFormat,
284 scope: Scope,
285 ) -> Result<(), Error> {
286 let id = sys::kAudioUnitProperty_StreamFormat;
287 let asbd = stream_format.to_asbd();
288 self.set_property(id, scope, Element::Output, Some(&asbd))
289 }
290
291 /// Return the current Stream Format for the AudioUnit.
stream_format(&self, scope: Scope) -> Result<StreamFormat, Error>292 pub fn stream_format(&self, scope: Scope) -> Result<StreamFormat, Error> {
293 let id = sys::kAudioUnitProperty_StreamFormat;
294 let asbd = self.get_property(id, scope, Element::Output)?;
295 StreamFormat::from_asbd(asbd)
296 }
297
298 /// Return the current output Stream Format for the AudioUnit.
output_stream_format(&self) -> Result<StreamFormat, Error>299 pub fn output_stream_format(&self) -> Result<StreamFormat, Error> {
300 self.stream_format(Scope::Output)
301 }
302
303 /// Return the current input Stream Format for the AudioUnit.
input_stream_format(&self) -> Result<StreamFormat, Error>304 pub fn input_stream_format(&self) -> Result<StreamFormat, Error> {
305 self.stream_format(Scope::Input)
306 }
307 }
308
309
310 unsafe impl Send for AudioUnit {}
311
312
313 impl Drop for AudioUnit {
drop(&mut self)314 fn drop(&mut self) {
315 unsafe {
316 use error;
317
318 // We don't want to panic in `drop`, so we'll ignore returned errors.
319 //
320 // A user should explicitly terminate the `AudioUnit` if they want to handle errors (we
321 // still need to provide a way to actually do that).
322 self.stop().ok();
323 error::Error::from_os_status(sys::AudioUnitUninitialize(self.instance)).ok();
324
325 self.free_render_callback();
326 self.free_input_callback();
327
328 error::Error::from_os_status(sys::AudioComponentInstanceDispose(self.instance)).ok();
329 }
330 }
331 }
332
333
334 /// Sets the value for some property of the **AudioUnit**.
335 ///
336 /// To clear an audio unit property value, set the data paramater with `None::<()>`.
337 ///
338 /// Clearing properties only works for those properties that do not have a default value.
339 ///
340 /// For more on "properties" see [the reference](https://developer.apple.com/library/ios/documentation/AudioUnit/Reference/AudioUnitPropertiesReference/index.html#//apple_ref/doc/uid/TP40007288).
341 ///
342 /// **Available** in iOS 2.0 and later.
343 ///
344 /// Parameters
345 /// ----------
346 ///
347 /// - **au**: The AudioUnit instance.
348 /// - **id**: The identifier of the property.
349 /// - **scope**: The audio unit scope for the property.
350 /// - **elem**: The audio unit element for the property.
351 /// - **maybe_data**: The value that you want to apply to the property.
set_property<T>( au: sys::AudioUnit, id: u32, scope: Scope, elem: Element, maybe_data: Option<&T>, ) -> Result<(), Error>352 pub fn set_property<T>(
353 au: sys::AudioUnit,
354 id: u32,
355 scope: Scope,
356 elem: Element,
357 maybe_data: Option<&T>,
358 ) -> Result<(), Error>
359 {
360 let (data_ptr, size) = maybe_data.map(|data| {
361 let ptr = data as *const _ as *const c_void;
362 let size = ::std::mem::size_of::<T>() as u32;
363 (ptr, size)
364 }).unwrap_or_else(|| (::std::ptr::null(), 0));
365 let scope = scope as c_uint;
366 let elem = elem as c_uint;
367 unsafe {
368 try_os_status!(sys::AudioUnitSetProperty(au, id, scope, elem, data_ptr, size))
369 }
370 Ok(())
371 }
372
373 /// Gets the value of an **AudioUnit** property.
374 ///
375 /// **Available** in iOS 2.0 and later.
376 ///
377 /// Parameters
378 /// ----------
379 ///
380 /// - **au**: The AudioUnit instance.
381 /// - **id**: The identifier of the property.
382 /// - **scope**: The audio unit scope for the property.
383 /// - **elem**: The audio unit element for the property.
get_property<T>( au: sys::AudioUnit, id: u32, scope: Scope, elem: Element, ) -> Result<T, Error>384 pub fn get_property<T>(
385 au: sys::AudioUnit,
386 id: u32,
387 scope: Scope,
388 elem: Element,
389 ) -> Result<T, Error>
390 {
391 let scope = scope as c_uint;
392 let elem = elem as c_uint;
393 let mut size = ::std::mem::size_of::<T>() as u32;
394 unsafe {
395 let mut data_uninit = ::std::mem::MaybeUninit::<T>::uninit();
396 let data_ptr = data_uninit.as_mut_ptr() as *mut _ as *mut c_void;
397 let size_ptr = &mut size as *mut _;
398 try_os_status!(
399 sys::AudioUnitGetProperty(au, id, scope, elem, data_ptr, size_ptr)
400 );
401 let data: T = data_uninit.assume_init();
402 Ok(data)
403 }
404 }
405
406 /// Gets the value of a specified audio session property.
407 ///
408 /// **Available** in iOS 2.0 and later.
409 ///
410 /// Parameters
411 /// ----------
412 ///
413 /// - **id**: The identifier of the property.
414 #[cfg(target_os = "ios")]
audio_session_get_property<T>( id: u32, ) -> Result<T, Error>415 pub fn audio_session_get_property<T>(
416 id: u32,
417 ) -> Result<T, Error>
418 {
419 let mut size = ::std::mem::size_of::<T>() as u32;
420 unsafe {
421 let mut data: T = ::std::mem::uninitialized();
422 let data_ptr = &mut data as *mut _ as *mut c_void;
423 let size_ptr = &mut size as *mut _;
424 try_os_status!(
425 sys::AudioSessionGetProperty(id, size_ptr, data_ptr)
426 );
427 Ok(data)
428 }
429 }
430