mono vs stereo output

[Zhenyu Tang]

Hi,

Great repo! Just had one question: when both target and reference are stereo I think everything makes sense. But if both of them are mono, current code converts the target to stereo on loading by duplicating its channel. After all the matching process, the output is a stereo file containing two identical channels, which is essentially mono. Would there be any issue if we don't convert the input/target to stereo in the beginning?

Thanks,
Zhenyu

[Сергей Гришаков]

Hey, Zhenyu!
Current matchering can only handle stereo internally.
In any case, it will try to calculate the mid and side channels, even if the target / reference audio was previously in mono.

Basically, this step will fail:

matchering/matchering/stage_helpers/match_levels.py

Line 139 in a05b1a8

 mid, side = lr_to_ms(array) 

Because the code assumes that there are exactly 2 channels:

matchering/matchering/dsp.py

Lines 57 to 64 in a05b1a8

 def lr_to_ms(array: np.ndarray) -> (np.ndarray, np.ndarray): 
     array = np.copy(array) 
     array[:, 0] += array[:, 1] 
     array[:, 0] *= 0.5 
     mid = np.copy(array[:, 0]) 
     array[:, 0] -= array[:, 1] 
     side = np.copy(array[:, 0]) 
     return mid, side 

[Сергей Гришаков]

And of course thank you for your kind words, @RoyJames.
They inspire. 😇

[Zhenyu Tang]

Thank you for the explanation. I'll do some changes on its output then.