Add ChannelConvertedReadableAudioFile for .mono() support when reading files.#453
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Add ChannelConvertedReadableAudioFile for .mono() support when reading files.#453psobot wants to merge 2 commits into
ChannelConvertedReadableAudioFile for .mono() support when reading files.#453psobot wants to merge 2 commits into
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gijzelaerr
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Mar 18, 2026
Fixes CI failures from psobot's spotify#453 (channel conversion feature): - Apply clang-format (LLVM style) to ReadableAudioFile.h, ChannelConvertedReadableAudioFile.h, and python_bindings.cpp - Add ChannelConvertedReadableAudioFile class to type stubs - Add mono(), stereo(), with_channels() method stubs to ReadableAudioFile, ResampledReadableAudioFile, and ChannelConvertedReadableAudioFile - Add resampled_to() method stubs to ResampledReadableAudioFile and ChannelConvertedReadableAudioFile (inherited from abstract base) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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We've had
ResampledReadableAudioFilefor a while now, providing a nice interface for on-the-fly resampling with.resampled_to(new_sample_rate). However, a common complaint is that there's no corresponding method for changing channel counts; users have to donp.mean(chunk, axis=0)instead to downmix.This PR adds
ChannelConvertedReadableAudioFile, which adds three new helpers for this:.mono(), which downmixes to a single channel.stereo(), which upmixes mono to stereo.with_channels(channel_count: int), which upmixes mono to any number of channels (or downmixes any number to mono).Downmixing to any number of channels other than 1 is currently not supported; there are multiple methods to go from 5.1 or other multichannel formats to stereo, and Pedalboard should not (yet) be opinionated about them.
Under the hood, to make this chaining work, I had to pull out
AbstractReadableAudioFileas a base class and do a bit of class hierarchy refactoring.