From bd7eff070558e88195fa1acf4a3212dc6b23129f Mon Sep 17 00:00:00 2001
From: Anthony Nicholls <anthony@juce.com>
Date: Thu, 13 Feb 2025 09:34:41 +0000
Subject: [PATCH] iOS: Fix an issue in which the reported sample rate may not
 always be correct

---
 .../native/juce_Audio_ios.cpp                 | 96 +++++++++----------
 1 file changed, 46 insertions(+), 50 deletions(-)

diff --git a/modules/juce_audio_devices/native/juce_Audio_ios.cpp b/modules/juce_audio_devices/native/juce_Audio_ios.cpp
index 288ecbec1f..7aad4e342b 100644
--- a/modules/juce_audio_devices/native/juce_Audio_ios.cpp
+++ b/modules/juce_audio_devices/native/juce_Audio_ios.cpp
@@ -481,66 +481,62 @@ struct iOSAudioIODevice::Pimpl final : public AsyncUpdater
     {
         auto session = [AVAudioSession sharedInstance];
 
-        if (exactlyEqual (session.sampleRate, rate))
-            return rate;
-
-        const auto startingSampleRate = session.sampleRate;
-
         setAudioSessionActive (false);
 
         JUCE_NSERROR_CHECK ([session setPreferredSampleRate: rate error: &error]);
 
         setAudioSessionActive (true);
 
-        if (! exactlyEqual (startingSampleRate, session.sampleRate))
-            return session.sampleRate;
-
-        AudioStreamBasicDescription stream{};
-        stream.mFormatID = kAudioFormatLinearPCM;
-        stream.mSampleRate = rate;
-        stream.mChannelsPerFrame = 2;
-        stream.mBitsPerChannel = 32;
-        stream.mFramesPerPacket = 1;
-        stream.mBytesPerFrame = stream.mChannelsPerFrame * stream.mBitsPerChannel / 8;
-        stream.mBytesPerPacket = stream.mBytesPerFrame * stream.mFramesPerPacket;
-        stream.mFormatFlags = stream.mBitsPerChannel;
-        stream.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger
-                            | kLinearPCMFormatFlagIsBigEndian
-                            | kLinearPCMFormatFlagIsPacked;
-
-        AudioQueueRef audioQueue;
-
-        auto err = AudioQueueNewOutput (&stream,
-                                        [] (auto, auto, auto) {},
-                                        nullptr,
-                                        nullptr,
-                                        kCFRunLoopCommonModes,
-                                        0,
-                                        &audioQueue);
-
-        if (err != noErr || audioQueue == nullptr)
+        if (@available (ios 18, *))
         {
+            AudioStreamBasicDescription stream{};
+            stream.mFormatID = kAudioFormatLinearPCM;
+            stream.mSampleRate = rate;
+            stream.mChannelsPerFrame = 2;
+            stream.mBitsPerChannel = 32;
+            stream.mFramesPerPacket = 1;
+            stream.mBytesPerFrame = stream.mChannelsPerFrame * stream.mBitsPerChannel / 8;
+            stream.mBytesPerPacket = stream.mBytesPerFrame * stream.mFramesPerPacket;
+            stream.mFormatFlags = stream.mBitsPerChannel;
+            stream.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger
+                                | kLinearPCMFormatFlagIsBigEndian
+                                | kLinearPCMFormatFlagIsPacked;
+
+            AudioQueueRef audioQueue;
+
+            auto err = AudioQueueNewOutput (&stream,
+                                            [] (auto, auto, auto) {},
+                                            nullptr,
+                                            nullptr,
+                                            kCFRunLoopCommonModes,
+                                            0,
+                                            &audioQueue);
+
+            if (err != noErr || audioQueue == nullptr)
+            {
+                jassertfalse;
+                return session.sampleRate;
+            }
+
+            const ScopeGuard disposeAudioQueueOnReturn { [&]
+            {
+                AudioQueueDispose (audioQueue, true);
+            }};
+
+            Float64 deviceSampleRate{};
+            UInt32 size = sizeof (deviceSampleRate);
+
+            err = AudioQueueGetProperty (audioQueue,
+                                         kAudioQueueDeviceProperty_SampleRate,
+                                         &deviceSampleRate,
+                                         &size);
+
+            if (err == noErr && size == sizeof (deviceSampleRate))
+                return deviceSampleRate;
+
             jassertfalse;
-            return session.sampleRate;
         }
 
-        const ScopeGuard disposeAudioQueueOnReturn { [&]
-        {
-            AudioQueueDispose (audioQueue, true);
-        }};
-
-        Float64 deviceSampleRate{};
-        UInt32 size = sizeof (deviceSampleRate);
-
-        err = AudioQueueGetProperty (audioQueue,
-                                     kAudioQueueDeviceProperty_SampleRate,
-                                     &deviceSampleRate,
-                                     &size);
-
-        if (err == noErr && size == sizeof (deviceSampleRate))
-            return deviceSampleRate;
-
-        jassertfalse;
         return session.sampleRate;
     }