High frequencies get cut?

[akx]

Hey there!

Kudos for the project – the results are pretty impressive already!

However, I noticed the default 2-stem model and the 5-stem model seem to cut higher frequencies from the material, like a (Nyquist?) knife really. I ran spleeter on a certain US pop star's song about temperature differences, i.e.

spleeter separate -i hot_n_cold.wav -o . -c wav

where hot_n_cold.wav is a pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s stream, then jury-rigged this A/B test environment in FL Studio where one can compare the original version and the summed stems. You can probably tell from the spectrogram in the below screenshot where I flipped the crossfade slider over to the Spleetered (Spleeted?) version.

The output stems are pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s, so it's not like the file itself is at fault here.

Is this expected? Can this be tuned/changed somehow?

[faroit]

It looks like all models only output up to 11 kHz. Would be nice to know if this is part of the model or stems from the original training data

[mmoussallam]

Hey Aarni,

Thanks for your feedback. Indeed the default behavior is to cut frequencies above 11Khz but it can be changed in the settings. Read this comment for details.

[faroit]

@mmoussallam but this still means that the models do not predict masks above 11khz, right? is this hardcoded in a training config?

[romi1502]

@faroit, yes, you're right: models are only trained until 11kHz and don't predict anything above.
This is set in the training config through the F parameter (see the wiki).
This is just a design choice that we made, when training the models we provide.

[akx]

@mmoussallam Thank you for the clarification!

[romi1502]

We've just updated the FAQ for making clearer how you can actually perform separation above 11kHz.
Notably we pushed alternate configuration files (spleeter:2stems-16kHz, spleeter:4stems-16kHz and spleeter:5stems-16kHz) that perform separation up to 16kHz and explained how you can set upper separation frequency in the config file if you need another value.

[khaleelyo]

Just a quick follow up,
I've been trying to incorporate the alternate 16kHz configuration using
spleeter separate -i audio_example.mp3 -o audio_output -p spleeter:4stems-16kHz
which raises the following error:
ERROR:spleeter:No embedded configuration 2stems-16kHz found
And
spleeter separate -i my_audio_file.mp3 -c spleeter:4stems-16kHz -o /output/path
which raises the following error:
spleeter separate: error: argument -c/--codec: invalid choice:

I'm currently running a Mac OSX, Python 3.7.3, I also attempted to reinstall spleeter with the same results. Any idea whats going on here?

Thanks,

[vkharatmal]

@khaleelyo

Try using this cmd :: python3 -m spleeter separate -i audio_example.mp3 -o output -p spleeter:2stems-16kHz