aiff | Battle tested aiff decoder/encoder | Messaging library

Hmm... I'm not entirely sure how this would work. It's my understanding that .wav and .aiff files are raw audio (maybe that's why you say you need to use them) I did find this answer Python change pitch of wav file but it uses python, which won't work for your Arduino, but its possible you could apply this technique using C++. Maybe someone else who knows more about this could take a look at that and explain how it might be done in C++

I dont think renaming the file extension will help you, you should use a file converter to make sure the audio data is beeing correctly encoded in another format. Try using SoundConverter

Workaround with bash:

AVAudioPlayerNode does not seem to be KVO-compliant for the isPlaying property. Normally the docs mention explicitly when properties are KVO-compliant but the docs for AVAudioPlayerNode don't address it directly

I ran a simple test using addObserver(_:forKeyPath:options:context:) and confirmed that KVO notifications are not emitted when play() or stop() is called.

As for why the Combine publisher exists, I assume that NSObject.KeyValueObservingPublisher works for all ObjC @property declarations whether or not the ObjC class internally handles the property in a KVO-compliant way (by sending -willChangeValueForKey: and -didChangeValueForKey:).

AIFF is usually big-endian. Try setting AVLinearPCMIsBigEndianKey to 1.

I suspect the issue here is Python's Global Interpreter Lock (GIL). In particular I'm guessing that when os.system is called in t1, the GIL locks and doesn't unlock until the command returns, preventing t2 from running any python code.

If I replace

Building and using the library aren't the same things.

Have a look at libavformat/oggdec.h and libavformat/oggdec.c. You should have realized, that there is no way to directly use the ogg_read_packet function.

1. there is no declaration in the header file
2. the function is declared static in the source file

If you want to encode/decode with a specific codec (here ogg), you have to find an encoder (avcodec_find_encoder or avcodec_find_encoder_by_name) or a decoder (avcodec_find_decoder or avcodec_find_decoder_by_name) and link it to a AVCodecContext via avcodec_open2.

Then for encoding use the 'encode' functions described here and for decoding the 'decode' functions described here.

For more info:

• FFmpeg Documentation
• FFmpeg Examples

In short, use the public Interface. Only 'God' knows the internals of FFmpeg.

The first thing I would fix is changing your @ObservedObject wrapper to a @StateObject wrapper. This will prevent deallocation if the view updates at some point in the process of playing the sound. Let me know if that works...

You should try upgrading Flow to v0.133 and switch to the Types-First architecture, or enable it on earlier releases. The rechecks have considerably improved, as explained, since all module exports are now annotated instead of being infered. There is a codemod availble for annotating exports on large codebases: