[macOS] Crash when 'Audio Mode' is set to 'Unity' in MacOS 26.0+

[michaelj909]

Unity version

6000.2.7f2

Unity editor platform

macOS

AVPro Video edition

Core

AVPro Video version

3.3.4

Device hardware

MacBook Pro 2020 M1 8GB, and MacBook Air 2022 M2 8GB

Which macOS version are you using?

Tahoe 26.1

Texture format

BGRA

Audio output

Unity

Any other Media Player component configuration required to reproduce the issue.

Screenshot of MacOS audio settings in MediaPlayer component attached. Through much testing we have identified the MacOS 'Audio Mode' setting as being the one that sets off the crash. When set to 'SystemDirect' our application runs without issue. When set to 'Unity' the crash occurs.

Which output component(s) are you using?

Audio Output, Display uGUI

Any other component configuration required to reproduce the issue.

Files (both video and audio) are always opened via script, from arbitrary (user-selected) locations on the user's drive, using the 'mediaplayer.OpenMedia(MediaPathType.AbsolutePathOrURL, [path])' method.

An 'AudioOutput' component is always present with each MediaPlayer instance, and a 'DisplayUGUI' instantiated as needed when the file in question is a video rather than mere audio.

The issue

Occasionally when playing a file (either video or audio) a segmentation fault will occur (see Log Output for an example) causing our application to close unexpectedly.

This issue doesn't occur every time that a file is played, but based on debug statements in our software when it does occur it always coincides with a 'mediaPlayer.Control.Play()' method call. Anecdotally it seems to occur more often on repeat plays of a file (even if other files are played between the first play of a file and its repeat play), though we haven't been able to definitively confirm this correlation in testing.

It should be noted that there are often multiple MediaPlayer component instances active at any one given time in our software (to allow for smoother crossfading/looping of media, and to layer different media on top of each other). The crash does seem to happen more often in more complex scenarios, but it is unclear to us whether it's the complexity of the scene itself contributing to the crash, or if it's simply a case that with more players the 'mediaPlayer.Play()' method is getting called more often thus meaning there are more opportunities for the segmentation fault to occur.

Through our testing we have also determined that this bug only started happening following the MacOS 26 'Tahoe' update. It did not seem to occur at all in MacOS 15.6.1 or earlier.

The bug is not related to Unity 6 specifically - we also experienced the exact same crash when building from Unity 2022.3.30f1.

Additionally, the bug is not unique to recent AVPro versions. We first encountered it with AVPro Video Core v2.9.3. We actually updated to Core v3.3.4 as a hail-Mary in the hopes that the new version of the asset would resolve it, but alas the issue is still there in the current version of AVPro too.

EDIT: Just to add, this bug only occurs in our built application. We have never experienced the crash in Unity Editor. Additionally, we compile from Unity Editor to an Xcode Project, then compile it from Xcode to the final .app.

Media information

The bug does not seem to be correlated to any one file or file format.

Our software uses AVPro to allow users to play back video and audio files from their file system. The bug in question has been reported in connected to multiple files of varying formats (including but not limited to mp4, mp3, wav, and m4a).

Log output

=================================================================
	Native Crash Reporting
=================================================================
Got a segv while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================

=================================================================
	Native stacktrace:
=================================================================
	0x11c0b938c - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : monovm_shutdown
	0x11c07b60c - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_unity_backtrace_from_context
	0x11c003d60 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_jit_set_domain
	0x19cd1f744 - /usr/lib/system/libsystem_platform.dylib : _sigtramp
	0x1b06a908c - /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox : _ZN2AQ3API6V2Impl37AudioQueueProcessingTapGetSourceAudioEP29OpaqueAudioQueueProcessingTapjP14AudioTimeStampPjS6_P15AudioBufferList
	0x1afd9ec98 - /System/Library/Frameworks/MediaToolbox.framework/Versions/A/MediaToolbox : FigAssetWriterCreateWithURL
	0x126982ce8 - /Applications/[APP NAME].app/Contents/PlugIns/AVProVideo.bundle/Contents/MacOS/AVProVideo : AVPPlayerGetCachedMediaStatusForURL
	0x1af96ce28 - /System/Library/Frameworks/MediaToolbox.framework/Versions/A/MediaToolbox : MTAudioProcessingTapGetStreamMediaTimeRange
	0x1b06c39b4 - /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox : _ZN5caulk12thread_proxyINSt3__15tupleIJNS_6thread10attributesEZN2AQ3API20ProcessingTapManager7RTStateC1ERKN10applesauce3xpc6objectERNS6_23ProcessingTapAttributesERiE3$_0NS2_IJEEEEEEEEPvSK_
	0x19cd15c08 - /usr/lib/system/libsystem_pthread.dylib : _pthread_start
	0x19cd10ba8 - /usr/lib/system/libsystem_pthread.dylib : thread_start

=================================================================
	Telemetry Dumper:
=================================================================
Thread 0x17086b000 may have been prematurely finalized* Assertion at mono-threads.c:702, condition `info' not met, function:mono_thread_info_current, 

An error has occured in the native fault reporting. Some diagnostic information will be unavailable.

=================================================================
	Native stacktrace:
=================================================================
	0x11c0b938c - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : monovm_shutdown
	0x11c211610 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : monoeg_assertion_message
	0x11c2054e4 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_thread_info_current_unchecked
	0x11c206bf8 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_thread_info_set_flags
	0x11c1ae684 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_threads_detach_coop
	0x11c0b95d4 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : monovm_shutdown
	0x11c07b60c - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_unity_backtrace_from_context
	0x11c003d60 - /Applications/[APP NAME].app/Contents/Frameworks/libmonobdwgc-2.0.dylib : mono_jit_set_domain
	0x19cd1f744 - /usr/lib/system/libsystem_platform.dylib : _sigtramp
	0x1b06a908c - /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox : _ZN2AQ3API6V2Impl37AudioQueueProcessingTapGetSourceAudioEP29OpaqueAudioQueueProcessingTapjP14AudioTimeStampPjS6_P15AudioBufferList
	0x1afd9ec98 - /System/Library/Frameworks/MediaToolbox.framework/Versions/A/MediaToolbox : FigAssetWriterCreateWithURL
	0x126982ce8 - /Applications/[APP NAME].app/Contents/PlugIns/AVProVideo.bundle/Contents/MacOS/AVProVideo : AVPPlayerGetCachedMediaStatusForURL
	0x1af96ce28 - /System/Library/Frameworks/MediaToolbox.framework/Versions/A/MediaToolbox : MTAudioProcessingTapGetStreamMediaTimeRange
	0x1b06c39b4 - /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox : _ZN5caulk12thread_proxyINSt3__15tupleIJNS_6thread10attributesEZN2AQ3API20ProcessingTapManager7RTStateC1ERKN10applesauce3xpc6objectERNS6_23ProcessingTapAttributesERiE3$_0NS2_IJEEEEEEEEPvSK_
	0x19cd15c08 - /usr/lib/system/libsystem_pthread.dylib : _pthread_start
	0x19cd10ba8 - /usr/lib/system/libsystem_pthread.dylib : thread_start

=================================================================
	External Debugger Dump:
=================================================================

Exiting early due to double fault.

[MorrisRH]

Have you configured Unity's Audio System Sample Rate setting or is it using the default? (Usually 48kHz but can depend on the audio output device).

Do you know if the audio requires resampling as part of playback? I.e. system sample rate is 48kHz and the audio track is 44.1kHz so requires upsampling to 48kHz.

[michaelj909]

I can confirm that our Unity project has Audio System Sample Rate set to 0 i.e. it uses the system default. In the case of MacOS (or at least for the M1 MacBook Pro) seems to be 44.1kHz.

As for the files that we believe are associated with the crash, the audio files (both mp3 and wav) mostly seem to be 44.1kHz, but the video files are more of a mixed hag with some at 44.1kHz and some with a 48kHz sample rate.

Notably, one of the video files (an mp4 specifically) that seems particularly likely to set off the crash has a 48kHz audio sample rate. So playback on MacOS using a video file with a higher sample rate than the system sample rate could definitely be a contributing factor to the crash.

[MorrisRH]

I've reproduced this and unfortunately it does appear to be an issue with Apple's Media Toolbox framework on macOS 26 (I've tested both 26.1 and 26.2).

It's unrelated to any audio processing we do as it occurs the first time the audio tap process callback is triggered after opening a video.

I am looking to see if some kind of work around is possible but so far no luck.