Re: Audio cracks with the iPad 11"
Re: Audio cracks with the iPad 11"
- Subject: Re: Audio cracks with the iPad 11"
- From: Dean Reyburn <email@hidden>
- Date: Thu, 15 Nov 2018 13:39:03 -0500
Hi Arshia,
I use Apple’s Audio Tool Box, everything I need is included in:
#include <AudioToolbox/AudioToolbox.h>
I’m calling:
AudioUnitSetProperty(), AudioUnitInitialize(), AudioOutputUnitStart() etc..
-Dean
PS It’s only the iPad *PRO* gen 3 that’s giving me issues.
PSS Apple is asking for a demo program and to report this as a bug.
> On Nov 15, 2018, at 12:39 PM, Arshia Cont <email@hidden> wrote:
>
> What service are you using to record your streams from RemoteIO? Extended
> Audio File Services? Audio File Services? AVAudioEngine magic?
>
> Reading your posts I have to buy a 3rd generation iPad! :) But know that if
> the system’s sample rate is at 48Khz and you are using 44.1khz, depending on
> the recording service you use, additional converter services will be
> introduced on the way to adapt services. And depending on your setup, it will
> consume resources and if your BufferDuration is low then you get glitches!
> Another source of glitch is of course if your Stream Formats do not comply
> (which again depending on services used can introduce additional cycle
> consuming converters that you don’t “see”).
>
> You can “see” them if you run your App on device and use Instrument’s “Time
> Profiler”. Just take a sample of runtime during recording and find the
> process that is taking too much time! Doing this you can sometimes find
> amazing things under the hood that you are introducing without wanting or
> not-recommended live DSP practices that you just missed (such as calling
> Shared singletons which cause glitches if called in the audio thread).
>
> Curious to know what you find until I receive my new iPad! :)
>
> Cheers,
>
>
> Arshia
>
>> On 15 Nov 2018, at 16:35, Dean Reyburn <email@hidden
>> <mailto:email@hidden>> wrote:
>>
>> A follow up:
>>
>> My iPhone XS Av session has a sampleRate of 48khz, however this device
>> records with a lot of distortion at 48khz. At 44.1khz the iPhone records
>> perfectly.
>>
>> So I’m still searching for a way to determine a reliable distortion free
>> recording rate on all devices. For now I can use 48khz only with the
>> “iPad8,x” but that’s a hack and the wrong way to do this in the long run.
>>
>> FWIW I’m using the play and record av session type.
>>
>> -Dean
>>
>>> On Nov 14, 2018, at 4:52 PM, Martin Man <email@hidden
>>> <mailto:email@hidden>> wrote:
>>>
>>> Hi Dean,
>>>
>>> What’s the
>>> https://developer.apple.com/documentation/avfoundation/avaudiosession/1616499-samplerate?language=objc
>>>
>>> <https://developer.apple.com/documentation/avfoundation/avaudiosession/1616499-samplerate?language=objc>
>>> reporting back to you?
>>>
>>> Martin (still unable to test on 11”)
>>>
>>>
>>>> On 14 Nov 2018, at 14:24, Dean Reyburn <email@hidden
>>>> <mailto:email@hidden>> wrote:
>>>>
>>>> Hi Pascal,
>>>> I have found a possible solution for my recording (only) app which was
>>>> giving distortion on iPad Pro gen 3 . My older versions record only at
>>>> 44.1khz. When I change to 48khz the recording is perfect. Either sample
>>>> rate works fine for my app, but I simply need to know during
>>>> intitialization which to use.
>>>>
>>>> I’m still talking to Apple DTS about how to detect whether a device wants
>>>> or needs 44.1khz or 48khz. There are no error returned when an iPad Pro
>>>> gen 3 from AudioUnitSetProperty() or any other audio units call on iPad
>>>> Pro 3 when starting recording. The iPad Pro 3 accepts 44.1khz and confirms
>>>> that it can do this sample rate with AudioUnitGetProperty() even though
>>>> the recording is distorted.
>>>>
>>>> So far I have not found how to detect the “default” or “native” recording
>>>> sample rate for a device if such a thing exists.
>>>>
>>>> -Dean
>>>>
>>>>> On Nov 14, 2018, at 5:02 AM, Flavio Antonioli <email@hidden
>>>>> <mailto:email@hidden>> wrote:
>>>>>
>>>>> Pascal,
>>>>>
>>>>> we have also received reports from some of our users of audio distortion
>>>>> on the new iPad Pro. We too are using RemoteIO.
>>>>> We don't currently have a device to test with so I wasn't able to
>>>>> reproduce the issue.
>>>>>
>>>>> Flavio.
>>>>>
>>>>> On Tue, Nov 13, 2018 at 9:00 PM <email@hidden
>>>>> <mailto:email@hidden>> wrote:
>>>>> Message: 2
>>>>> Date: Tue, 13 Nov 2018 16:43:53 +0100
>>>>> From: Pascal Douillard <email@hidden
>>>>> <mailto:email@hidden>>
>>>>> To: email@hidden <mailto:email@hidden>
>>>>> Subject: Audio cracks with the iPad 11"
>>>>> Message-ID: <email@hidden
>>>>> <email@hidden">mailto:email@hidden>>
>>>>> Content-Type: text/plain; charset=utf-8
>>>>>
>>>>> Hi everyone,
>>>>>
>>>>> I have an audio app for iPad & iPhone and I have been getting audio
>>>>> cracks on the new iPad Pro 11”. The cracks happen on speakers and on
>>>>> headphones on the USB-C port but not when using bluetooth headphones like
>>>>> the Air Pods.
>>>>>
>>>>> They do not happen on any of the other iPads or iPhone.
>>>>>
>>>>> The audio engine is in C++ and is running in Core Audio using a single
>>>>> RemoteIO unit. No extra audio libraries are used.
>>>>>
>>>>> This is not related to the forced 48K sample rate of the iPad 11” as the
>>>>> app runs fine with the same sample rate on other devices.
>>>>>
>>>>> Anyone else has experienced the same? Thanks.
>>>>>
>>>>> Pascal
>>>>>
>>>>> ------------------------------
>>>>>
>>>>> Subject: Digest Footer
>>>>>
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>>>>>
>>>>> ------------------------------
>>>>>
>>>>> End of Coreaudio-api Digest, Vol 15, Issue 94
>>>>> *********************************************
>>>>>
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>>>>
>>>> 1-888-SOFT-440 or 1-888-763-8440
>>>> Reyburn CyberTuner, Inc.
>>>> http://www.cybertuner.com <http://www.cybertuner.com/>
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>>
>> 1-888-SOFT-440 or 1-888-763-8440
>> Reyburn CyberTuner, Inc.
>> http://www.cybertuner.com <http://www.cybertuner.com/>
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Reyburn CyberTuner, Inc.
http://www.cybertuner.com
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