[Xiaomi Mi 8 ROMs, Kernels, Recoveries, & Other Dev] :
[MENTION=1187148]infrag[/MENTION] I've downloaded LOS sources then edited Dialer package to change the CallRecordings source.

I've changed from "CallRecordings" to "Music/CallRecordings" the PUBLIC_DIRECTORY_NAME constant, that specifies the recordings pathname from /sdcard

- private static final String PUBLIC_DIRECTORY_NAME = "CallRecordings";
+ private static final String PUBLIC_DIRECTORY_NAME = "Music/CallRecordings";

at the file

java/com/android/dialer/callrecord/CallRecording.java

then recompiled, then updated at /system/proc/priv-app/Dialer.apk

then now Calls are been recorded.

With this change the recording calls works even if sdk is set to 29 in Android Manifest.

Please, can you update commit into the Dialer sources to make this change permanent?

EDIT:

I apologize, but with the change above, the records are correcly stored at /sdcard/Music/CallRecordings, but there are a issue when click on a recording over calls log.

For now maybe the solution is to change the sdk from 29 to 28 into the Manifest and wait until a expert solves the issue.

06-01 15:39:42.084 14400 14400 E AndroidRuntime: java.lang.IllegalArgumentException: Failed to find configured root that contains /storage/emulated/0/Music/CallRecordings/1470_200601_153841556.amr
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.support.v4.content.FileProvider$SimplePathStrategy.getUriForFile(FileProvider.java:13)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:2)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at com.android.dialer.calldetails.CallDetailsEntryViewHolder.playRecording(CallDetailsEntryViewHolder.java:2)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at com.android.dialer.calldetails.CallDetailsEntryViewHolder.lambda$setCallDetails$0$CallDetailsEntryViewHolder(CallDetailsEntryViewHolder.java:3)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at com.android.dialer.calldetails.-$$Lambda$CallDetailsEntryViewHolder$si39-xOemvUlrhbEvcrvq0TDhGc.onClick(Unknown Source:4)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.view.View.performClick(View.java:7259)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.view.View.performClickInternal(View.java:7236)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.view.View.access$3600(View.java:801)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.view.View$PerformClick.run(View.java:27892)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.os.Handler.handleCallback(Handler.java:883)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.os.Handler.dispatchMessage(Handler.java:100)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.os.Looper.loop(Looper.java:214)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at android.app.ActivityThread.main(ActivityThread.java:7356)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at java.lang.reflect.Method.invoke(Native Method)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
06-01 15:39:42.084 14400 14400 E AndroidRuntime:	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
06-01 15:39:42.087 1303 4617 W ActivityTaskManager: Force finishing activity com.android.dialer/.calldetails.OldCallDetailsActivity