[PD] Libpd running in OS X app

Tue Jul 9 05:23:23 CEST 2013

Ah, that's right I forgot: using one AUHAL audio unit only works if you are
using the same device for input and output, otherwise you need to create
two as you found out. Unfortunately this is the default setup on a macbook,
but I found that it still works if you create an "Aggregate Device" in the
'Audio Midi Setup' preference pane (it'll also work with hardware sound I/O
interfaces).

Yea not sure how to leave those samples / what modifications to make to
PdAudioUnit - if you get something working that is fairly general maybe we
can work it in.

About the AUGraph, the limitation I ran into was trying to feed either
speech synthesis or AUFilePlayer output into pd from a render callback - I
could only get it to work with straight Audio Units and
AudioUnitSetProperty.  See here for the gory details:

http://lists.apple.com/archives/coreaudio-api/2013/Jan/msg00009.html

cheers,
Rich

On Mon, Jul 8, 2013 at 6:20 AM, Joe White <white.joe4 at gmail.com> wrote:

> Thanks for the link Rich!
>
> I had a look at your code and I could get the tone patch to work with
> input disabled, but enabling input caused an error:
>
> * *** ERROR *** -[PdAudioUnit
> initAudioUnitWithSampleRate:numberChannels:inputEnabled:][159] status code
> =  kAudioUnitErr_InvalidPropertyValue*
>
> I think this is due to the fact that with kAudioUnitSubType_HALOutput you
> need to set up two callbacks for input/output processing:
>
> *kAudioOutputUnitProperty_SetInputCallback* for retrieving the input
> samples by calling the AudioUnitRender() method, processing the samples and
> storing them into a ring buffer.
>
>  *kAudioUnitProperty_SetRenderCallback* for retrieving the samples stored
> in the ring buffer to output.
>
>
> I have a HAL Output Unit working with AUGraph in a controller class. I'll
> try and wrap it up this week and share it.
>
> However for this purpose I didn't need audio input so I opted for the
> Default Output unit. As you can see in the link from the previous email
> this simplifies the code A LOT :) Maybe it'd be useful to have two projects
> for output only and input/output. With the former being a very quick way
> for people new to libpd to get a project up and running.
>
> Regarding my issue with libpd not processing audio, as Dan pointed out, it
> *should *be working. However, thinking about it more it could be due to
> how I built the libpd library. I noticed Rich added the whole source code
> into his project so I'll try that and see if it makes any difference. Weird!
>
> Thanks for the help guys,
>
> Joe
>
> On 7 July 2013 03:02, Rich E <reakinator at gmail.com> wrote:
>
>> I started adding support for using PdAudioUnit in a Cocoa / OS X app
>> (PdAudioController is too iOS-specific) and checked my progress into the
>> cocoa branch here:
>>
>> https://github.com/libpd/libpd/tree/cocoa
>>
>> There is a (very basic) working app at:
>>
>>
>> https://github.com/libpd/libpd/tree/cocoa/samples/cocoa_samples/CocoaPdBasic
>>
>> You can also find some experimentation I did with moving towards an
>> AUGraph design but, in the end, I found it much more restrictive than just
>> using Audio Units directly.  Apologies for not finding the time to finish
>> this, I've been working full-time on a different project for many months
>> now... but hopefully once that is done I will finish off those samples,
>> unless someone else already has.
>>
>> In essence, there were only a few things that needed to be modified. Off
>> the top of my head, they were:
>>
>> - switch the audio unit to kAudioUnitSubType_HALOutput
>> - enable an input audio device (required on OS X, not on iOS)
>> - fix some Obj-C syntax issues that are different on OS X (property
>> synthesis generation I believe)
>>
>> By the way, you can use the C++ wrapper quite readily with any other
>> existing audio framework that provides OS X support - I use it in cinder
>> apps and of course Dan provides ofxPd.  I know others who have used
>> portaudio or FMOD directly.
>>
>> cheers,
>> Rich
>>
>>
>> On Sat, Jul 6, 2013 at 9:04 AM, Dan Wilcox <danomatika at gmail.com> wrote:
>>
>>> Sorry. I assumed you were using the existing Obj-C PdAudioUnit and
>>> PdAudioController classes included with libpd which were written mainly for
>>> iOS. We should get around to tweaking it so it works on OSX. Did you try it?
>>>
>>> In skimming your code, it looks like you're doing everything the
>>> PAudioUnit does, so I don't see any obvious problems.
>>>
>>>
>>> On Jul 6, 2013, at 8:52 AM, Joe White <white.joe4 at gmail.com> wrote:
>>>
>>> Sorry that previous code had some test stuff in it, here's a slightly
>>> cleaner version (ARC'd)
>>>
>>> http://pastebin.com/index/1bR2Ftqn
>>>
>>> On 6 July 2013 13:47, Joe White <white.joe4 at gmail.com> wrote:
>>>
>>>> How do you mean the CoreAudio backend? I would have thought I should
>>>> just be able to call the process function in my render callback. Did you
>>>> check out the code I posted? I happy to provide that as an AudioController
>>>> for libpd on OSX. Messages and print objects work correctly but libpd is
>>>> not processing any audio.
>>>>
>>>> http://pastebin.com/1bR2Ftqn
>>>>
>>>> Cheers,
>>>> Joe
>>>>
>>>>
>>>> On 5 July 2013 23:33, Dan Wilcox <danomatika at gmail.com> wrote:
>>>>
>>>>> As far as I know, the OSX port isn't finished and the CoreAudio
>>>>> backend isn't hooked up. Anyone wanna help out there or sponsor us? :D
>>>>>
>>>>> On Jul 5, 2013, at 7:56 AM, pd-list-request at iem.at wrote:
>>>>>
>>>>> *From: *Joe White <white.joe4 at gmail.com>
>>>>>  *Subject: **[PD] Libpd running in OS X app*
>>>>> *Date: *July 5, 2013 7:34:47 AM EDT
>>>>> *To: *pd-list <pd-list at iem.at>
>>>>>
>>>>>
>>>>> Hi guys,
>>>>>
>>>>> Does anyone have any experience running libpd in an OS X app, using
>>>>> CoreAudio.
>>>>>
>>>>> I'm able to run a patch and receive print statements but I'm not
>>>>> getting any audio output and DSP doesn't seem to be processing. I created a
>>>>> quick test tone in code to see if it was my audio unit but that works. My
>>>>> main problem it seems is that after calling
>>>>>
>>>>>   [PdBase processFloatWithInputBuffer:leftBuffer outputBuffer
>>>>> :leftBuffer ticks:ticks];
>>>>>
>>>>> ...the buffer is still empty. Anyone have any ideas?
>>>>>
>>>>> I'm calling [PdBase computeAudio:] just before I start the AudioUnit.
>>>>> Here's the whole controller class if that helps:
>>>>> http://pastebin.com/eYf1Facp
>>>>>
>>>>> Any help would be much appreciated!
>>>>>
>>>>> Many thanks,
>>>>>
>>>>> Joe
>>>>>
>>>>>
>>>>>  --------
>>>>> Dan Wilcox
>>>>> @danomatika
>>>>> danomatika.com
>>>>> robotcowboy.com
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Follow me on Twitter @diplojocus
>>>>
>>>
>>>
>>>
>>> --
>>> Follow me on Twitter @diplojocus
>>>
>>>
>>>  --------
>>> Dan Wilcox
>>> @danomatika
>>> danomatika.com
>>> robotcowboy.com
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Pd-list at iem.at mailing list
>>> UNSUBSCRIBE and account-management ->
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>>>
>>
>
>
> --
> Follow me on Twitter @diplojocus
>
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