Re: Playing hi-res audio through external DAC
Re: Playing hi-res audio through external DAC
- Subject: Re: Playing hi-res audio through external DAC
- From: "Stephen F. Booth" <email@hidden>
- Date: Wed, 18 Apr 2018 23:09:51 +0000
I believe you're after kAudioDevicePropertyNominalSampleRate.
See https://developer.apple.com/library/content/qa/qa1196/_index.html for a
code sample and more information.
Stephen
On Wed, Apr 18, 2018 at 5:33 PM Kenny Leung <email@hidden> wrote:
> Yes it does, just like any other audio output device. That’s not my issue.
> The issue is how to make the OS output to that device at the desired
> bitrate programmatically. I know I can change the bitrate in Audio Midi
> Setup manually.
>
> -Kenny
>
>
> On Apr 18, 2018, at 2:37 PM, Patrick Cusack <email@hidden> wrote:
>
>
>
> On Apr 18, 2018, at 2:25 PM, Kenny Leung <email@hidden> wrote:
>
> Hi Patrick.
>
> I’m trying to write my own hi-res audio player. I’ve already been
> successful in playing a 24/192kHz audio file on both iOS and macOS using
> code based on what is written here:
> https://developer.apple.com/library/content/documentation/MusicAudio/Conceptual/AudioQueueProgrammingGuide/AQPlayback/PlayingAudio.html
>
> However, the CoreAudio system automatically converts the sample rate
> internally to whatever the output rate is set to (via Audio Midi Setup on
> Mac, and some unknown method on iOS).
>
> On iOS, you can set AVAudioSession.sampleRate, but output still won’t go
> higher than 48kHz.
>
> I’m using an XDuoo XD-05 (
> http://www.xduoo.com/xduoo/En/ProductView.Asp?ID=17) with a display, so
> it tells me what the phone is outputting. I can use Onkyo player to play at
> 24/192kHz, but I can’t get my own app to play at any more than 48kHz.
> Sample rate conversion is precisely the thing I am trying to get away from.
>
>
> Does the XDuoo shows up as an output device in OSX? Specifically in the
> Sound system preferences?
>
>
> Thanks.
>
> -Kenny
>
>
> On Apr 18, 2018, at 12:12 PM, Patrick Cusack <email@hidden>
> wrote:
>
> Your output device is going to determine your sample rate. Any audio you
> play is going to be float so 24 bit isn’t a consideration as you will
> convert the 24bit audio to float. As for your 192kHz audio, you will either
> need to play it out of 192kHz device or perform sample rate conversion in
> your audio graph.
>
> This stack overflow listing discusses handling sample rate conversion:
>
>
> https://stackoverflow.com/questions/6610958/os-x-ios-sample-rate-conversion-for-a-buffer-using-audioconverterfillcomplex
>
>
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