SoundCard is a library for playing and recording audio without resorting to a CPython extension. Instead, it is implemented using the wonderful CFFI and the native audio libraries of Linux, Windows and macOS.
SoundCard is cross-platform, and supports Linux/pulseaudio, Mac/coreaudio, and Windows/WASAPI. While the interface is identical across platforms, naming schemes and block sizes can vary between devices and platforms.
SoundCard is still very early in its development. All major building blocks are in place, but I fully expect there to be bugs and possibly crashes. If you find a bug, please open an Issue, and I will try to fix it. Or open a Pull Request, and I will try to include your fix into SoundCard.
However, please be aware that this is a hobby project of mine that I am developing for free, and in my spare time. While I try to be as accomodating as possible, I can not guarantee a timely response to issues. Publishing Open Source Software on Github does not imply an obligation to fix your problem right now. Please be civil.
Here is how you get to your Speakers and Microphones:
import soundcard as sc
speakers = sc.all_speakers()
default_speaker = sc.default_speaker()
mics = sc.all_microphones()
default_mic = sc.default_microphone()
# search by substring:
one_speaker = sc.get_speaker('Scarlett')
one_mic = sc.get_microphone('Scarlett')
# fuzzy-search:
one_speaker = sc.get_speaker('FS2i2')
one_mic = sc.get_microphone('FS2i2')All of these functions return Speaker and Microphone objects, which can be used for playback and recording. All data passed in and out of these objects are frames × channels Numpy arrays.
import numpy
print(default_speaker)
>>> <Speaker alsa_output.usb-Focuswrite_Scarlett_2i2_USB-00-USB.analog-stereo (2 channels)>
print(default_mic)
>>> <Microphone alsa_input.usb-Focuswrite_Scarlett_2i2_USB-00-USB.analog-stereo (2 channels)>
# record and play back one second of audio:
data = default_mic.record(samplerate=44100, numframes=44100)
default_speaker.play(data/numpy.max(data), samplerate=44100)
# alternatively, get a `recorder` and `player` object and play or record continuously:
with default_mic.recorder(samplerate=44100) as mic, default_speaker.player(samplerate=44100) as sp:
for _ in range(100):
data = mic.record(numframes=1024)
sp.play(data)Some professional sound cards have large numbers of channels. If you want to record or play only a subset of those channels, you can specify a channel map. For playback, a channel map of [0, 3, 4] will play three-channel audio data on the physical channels one, four, and five. For recording, a channel map of [0, 3, 4] will return three-channel audio data recorded from the physical channels one, four, and five.
Currently, channel maps do not work on Windows (beyond reordering). The API does not seem to support it. If you know how to implement channel maps on Windows, I'd be grateful for a hint!
In addition, pulseaudio/Linux defines channel -1 as the mono mix of all channels for both playback and recording. CoreAudio/macOS defines channel -1 as silence for both playback and recording.
- Windows/WASAPI currently records garbage if you record only a single channel. Multi-channel and channel maps work, though.
- Error messages often report some internal CFFI/backend errors. This will be improved in the future.
- Documentation is not great yet. This will be improved in the future.
- Windows/WASAPI silently ignores the blocksize. The reason for this is still unknown.
- 2018-04-25 implements fixed block sizes when recording (thank you, Pariente Manuel!)
- 2018-05-10 adds a test suite and various fixes for Windows
- 2018-05-11 various fixes for macOS
Copyright (c) 2016 Bastian Bechtold All rights reserved.
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