# 16_mac_audio_vpio_disable.patch
#
# Port of deps/patches/16_mac_audio_device_fix.patch from the 2.12 series.
#
# Without this patch, pjsip's CoreAudio backend detects the
# VoiceProcessingIO audio unit and sets cf->has_vpio = PJ_TRUE, which makes
# it announce PJMEDIA_AUD_DEV_CAP_EC on every device. The Python layer
# (SIPApplication) takes the EC capability as a hint to use the Voice
# Processing IO unit when opening the mic.
#
# Opening VPIO causes macOS to instantiate a transient virtual aggregate
# device named "VPAUAggregateAudioDevice-0x<addr>". Because patch 05
# (audio device observer) is now in effect, every appearance and
# disappearance of this aggregate device fires
# kAudioHardwarePropertyDevices listener -> DEVICE_LIST_CHANGED ->
# pjmedia_aud_dev_refresh -> AudioDevicesDidChange -> Python re-opens
# the audio session -> new aggregate device created -> loop.
#
# Symptom seen on 2.17 build (3 June 2026):
#   Added audio device(s): VPAUAggregateAudioDevice-0x115811840
#   Removed audio device(s): VPAUAggregateAudioDevice-0x115811840
#   Added audio device(s): VPAUAggregateAudioDevice-0x114a61040
#   ... (forever; cannot exit the program)
#
# Fix: comment out the VPIO detection. has_vpio stays PJ_FALSE, no EC cap
# advertised, app uses the default HALOutput unit, no aggregate device
# storm.
#
# Note: the EC capability bit was only ever advertised on Mac; on iOS the
# code path is different. Disabling VPIO on Mac matches the 2.12 behaviour
# the application was originally tested against.
#
--- pjsip/pjmedia/src/pjmedia-audiodev/coreaudio_dev.m.orig
+++ pjsip/pjmedia/src/pjmedia-audiodev/coreaudio_dev.m
@@ -286,9 +286,12 @@
     if (cf->io_comp == NULL)
         return PJMEDIA_EAUD_INIT; // cannot find IO unit;

+    /*
+    Disabled — see deps/patches/2.17/16_mac_audio_vpio_disable.patch.
     desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO;
     if (AudioComponentFindNext(NULL, &desc) != NULL)
         cf->has_vpio = PJ_TRUE;
+    */

     status = ca_factory_refresh(f);
     if (status != PJ_SUCCESS)