Add noisered and ladspa in sox_effects

noisered and ladspa from here are not listed as an effect. Not picked up due to its interface?

>>> from torchaudio.sox_effects.sox_effects import effect_names
>>> torchaudio.__version__
'0.7.0a0+ac17b64'
>>> effect_names()
['allpass', 'band', 'bandpass', 'bandreject', 'bass', 'bend', 'biquad', 'chorus', 'channels', 'compand', 'contrast', 'dcshift', 'deemph', 'delay', 'dither', 'divide', 'downsample', 'earwax', 'echo', 'echos', 'equalizer', 'fade', 'fir', 'firfit', 'flanger', 'gain', 'highpass', 'hilbert', 'loudness', 'lowpass', 'mcompand', 'norm', 'oops', 'overdrive', 'pad', 'phaser', 'pitch', 'rate', 'remix', 'repeat', 'reverb', 'reverse', 'riaa', 'silence', 'sinc', 'speed', 'stat', 'stats', 'stretch', 'swap', 'synth', 'tempo', 'treble', 'tremolo', 'trim', 'upsample', 'vad', 'vol']
>>> 'noisered' in effect_names()
False

It affects facebookresearch/WavAugment#16.

[rien333]

@mthrok Thanks for your quick and detailed reply! Following your instructions, I was able to add ladspa support.

[mthrok]

Hi @rien333

The build process has been changed since the time of above discussion, and ladspa is indeed explicitly disabled. This is because now we only support static build of libsox and because of an issue with in-memory decoding (for file-like object support) and many binary distribution of libsox provided by package manager has the issue. The issue with in-memory decoding has been patched on the latest dev version but there is no release that includes the patch.

I did not know much about ladspa, but according to your finding, the possible way to support is,

1. install the latest libsox with dynamic linking and ladspa support (if file-like object support matters, otherwise you can use the version from your system’s package manager)
2. change the way torchaudio is built so that it links to the libsox from step 1.

Step 2. is not straightforward for us because we do not know how many different environments we need to support, and this makes the build process prune to configuration errors. If you would like to try, you can look at the previous version of CMakeLists.txt. You need to make sure that the version of libsox you want to use shows up first in the search path.