# How to create discrete mono tracks with AVFoundationMBS

**URL:** <https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327>\
**Category:** Extras\
**Created:** [April 12, 2023, 10:39am UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327 "2023-04-12T10:39:54Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![OJAN](https://forum.xojo.com/letter_avatar_proxy/v4/letter/o/f1d935/32.png) [@OJAN](https://forum.xojo.com/u/OJAN)\
**Post date:** [April 12, 2023, 10:39am UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327/1 "2023-04-12T10:39:55Z")

</div>

Using these settings:

```auto
Var recordSetting as new Dictionary

Var n as integer = OSTypeFromStringMBS(AVFoundation.kAudioFormatAppleLossless)
recordSetting.Value(AVFoundationMBS.AVFormatIDKey) = n
recordSetting.Value(AVFoundationMBS.AVSampleRateKey) = 48000.0
recordSetting.Value(AVFoundationMBS.AVNumberOfChannelsKey) = 2
recordSetting.Value(AVFoundationMBS.AVLinearPCMBitDepthKey) = 24
recordSetting.Value(AVFoundationMBS.AVLinearPCMIsBigEndianKey) = false
recordSetting.Value(AVFoundationMBS.AVLinearPCMIsFloatKey) = false

```

gives me an audiofile with one stereo track.

How can I create an audiofile with two discrete mono tracks?

---

<div class="post-metadata">

**Author:** ![Christian\_Schmitz](https://forum.xojo.com/user_avatar/forum.xojo.com/christian_schmitz/32/158_2.png) [@Christian\_Schmitz](https://forum.xojo.com/u/Christian_Schmitz)\
**Post date:** [April 12, 2023, 11:43am UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327/2 "2023-04-12T11:43:38Z")

</div>

So convert one stereo track to two tracks with each mono audio?

---

<div class="post-metadata">

**Author:** ![OJAN](https://forum.xojo.com/letter_avatar_proxy/v4/letter/o/f1d935/32.png) [@OJAN](https://forum.xojo.com/u/OJAN)\
**Post date:** [April 12, 2023, 12:10pm UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327/3 "2023-04-12T12:10:27Z")

</div>

Not convert, but record from stereo source and save an audiofile with two discrete mono tracks.

---

<div class="post-metadata">

**Author:** ![Christian\_Schmitz](https://forum.xojo.com/user_avatar/forum.xojo.com/christian_schmitz/32/158_2.png) [@Christian\_Schmitz](https://forum.xojo.com/u/Christian_Schmitz)\
**Post date:** [April 12, 2023, 12:23pm UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327/4 "2023-04-12T12:23:07Z")

</div>

Sorry, I don’t know how to do this.

I would suggest looking into AVChannelLayoutKey to define a channel map.  
This allows to map channels and helped us in a few cases already.

It could also be required to make two recording, so that each one records one of the channels.

---

<div class="post-metadata">

**Author:** ![OJAN](https://forum.xojo.com/letter_avatar_proxy/v4/letter/o/f1d935/32.png) [@OJAN](https://forum.xojo.com/u/OJAN)\
**Post date:** [April 12, 2023, 12:39pm UTC](https://forum.xojo.com/t/how-to-create-discrete-mono-tracks-with-avfoundationmbs/75327/5 "2023-04-12T12:39:32Z")

</div>

Thank you, Christian.  
I’ve already looked at it – but I don’t know how to use it.  
Making two recordings is not an option