Catalina Beta 5：Quicktime录音不适用于2018 Macbook Pros sw

Question

Starting a Quicktime Audio recording with Catalina Dev Beta 5 on 2018 or later Macbook Pros outputs files with no sound (Macbook Pro Microhone selected). Example file here: https://www.dropbox.com/s/ib67k0vg8cm93fn/test_no_audio%20%281%29.aifc?dl=0

During the recording recording Console shows this error:

"CMIO_Unit_Converter_Audio.cpp:590:RebuildAudioConverter AudioConverterSetProperty() failed (1886547824)"

We have an application that records the screen and audio at the same time using AVFoundation and the resulting video files also do not have audio. However when inspecting the CMSampleBuffers, they seem fine: https://gist.github.com/paulius005/faef6d6250323b7d3386a9a70c08f70b

Is anyone else experiencing this issue or possibly have more visibility if it's something Apple is working on?

Anything else that I should be looking at to tackle the issue?

Answer 1

Yes, Apple is changing a lot of things related to the audio subsystem layer on Catalina. I am aware that various audio applications are being rewritten for Catalina. Also since beta2, each new beta release comes with some deprecations, but also comes with some new implementations [to the new audio layer of the MacOS].

Current Beta 5 Audio Deprecations:

• The OpenAL framework is deprecated and remains present for compatibility purposes. Transition to AVAudioEngine for spatial audio functionality.

• AUGraph is deprecated in favor of AVAudioEngine.

• Inter-App audio is deprecated. Use Audio Units for this functionality.

• Carbon component-based Audio Units are deprecated and support will be removed in a future release.

• Legacy Core Audio HAL audio hardware plug-ins are no longer supported. Use Audio Server plug-ins for audio drivers.

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About AVFoundation [which you are using]:

Deprecated on Beta 5:

• The previously deprecated 32-bit QuickTime framework is no longer available in macOS 10.15.

• The symbols for QTKit, which relied on the QuickTime framework, are still present but the classes are non-functional .

The above item: Apple shipped the symbols for QTkit on Catalina Beta 5, but they are nulled, non-functional. This means, an application will run, but will not produce any result if it is using those AVFoundation classes. (I don't know if those deprecations directly or indirectly affects your program, but they are about AVFoundation)

I think they will be fully removed on next betas, but for now they are nulled non-functional, otherwise it would completely cause instant crashes on many audio/AV applications which tried to load them. This seems to be going like a step-by-step "migration thing" from beta to beta, to give time(?) to developers rewrite their audio apps to the new audio subsystem.

You can find more details on the release notes [along with links to some new classes and functions documentation to replace the deprecated ones], but it is not a good/rich documentation yet.

https://developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_beta_5_release_notes

PS: About my opinions, point of view and information written here: I am a senior MacOS developer, but not on AV/Audio/Media subsystem, my area is Kernel/Networking/Security. But I am closely following all the changes that are happening to the MacOS operating system on each Catalina beta release since the first, and the changes I am noticing that Apple is making on the audio subsystem are significant changes.

I cannot specifically help you with the audio programming issue, but you asked if it could be something Apple is working on, and yes, it is.

I hope this information can help you get complementary information to solve your application issue.