VR settings
Explained in detail
Settings available in Colab and in CLI branch, and also UVR 5 GUI (but without at least mirroring2. mirroring in UVR5 GUI for VR arch got replaced entirely by High End Process (works as mirroring now, and not like original High End Process which was originally dedicated for very old 16kHz VR models only).
These VR models can be used in this 1) Colab or in 2) UVR5 GUI or on 3) mvsep.com (uses 512 windows size, aggressiveness option, various models) 4) x-minus.pro/uvronline.app (for free one UVR (unreleased) model without parameters ("lo-fi" option, mp3, 17,7 kHz cutoff) [Demucs 4 for registered users iirc (site by Aufr33 - one of the authors of UVR5)]
I had at least one report that results for just VR models are better using Colab above/old CLI branch instead of the newest UVR5 GUI, so be aware (besides both mirroring settings - only mirroring is working under high-end process - no mirroring2 [272 window size is added back as user input] all settings should be available in GUI). Interestingly, I received similar report for MDX models in UVR5 GUI comparing to Colab (be aware just in case). The problems might be also bound to VRAM, and don't exist on 11GB GPPUs and up or in CPU mode.
Before we start -
Issue with additional vocal residues when postprocess is enabled
- “postprocess option masks instrumental part based on the vocals volume to improve the separation quality." (from: https://github.com/tsurumeso/vocal-remover)
where in HV Colab it says: “Mute low volume vocals”. So, if it enhances separation quality, then maybe it should cancel some vocals residues ("low volume vocals") so that's maybe not too bad explanation.
But that setting enabled in at least Colab may leave some vocal residues:
(it’s fixed in UVR GUI "the very end bits of vocals don't bleed anymore no matter which threshold value is used")
Customizable postprocess settings (threshold, min range and fade size) in HV's Colab were deleted, and were last time available in this revision:
So change default 0.3 or 0.2 threshold value (depending on revision) and set it to 0.01 if you have the issue when using postprocess.
The threshold parameter set to 0.01 fixes the issue (so quiet the opposite thing happened using default settings than this option should serve to, I believe).
Also, default threshold values for postprocess changed from 0.3 to 0.2 in later revisions of the Colab.
- Window size option set to anything other than 512 somehow decrease SDR, although most people like lower values (at least 320, me even 272; 352 is also possible, but anything above changes the tone of sound more noticeably) - we don’t know yet why lower window sizes mess with SDR (similar situation like with GSEP) - 512 might be a good setting for ensemble with other models than VR ones or for further mastering. Sometimes compared to 512 windows size, 272 can lead to a bit more noticeable vocal residues. You might find bigger window sizes less noisy in general, but also more blurry for some people.
- Aggressiveness/Aggression - “A value of 10 is equivalent to 0.1 (10/100=0.1) in Colab”.
Strangely, the best SDR for aggressiveness using MSB2 instrumental model turned out to be 100 in GUI, 10 in Colab, while we usually used 0.3 for this model and 500m_x as well, while HP models usually behaves the best with lower values than HP2 models (0.09/10 in GUI).
- Mirroring turned out to enhance SDR. It adds to the spectrum e.g. above 20kHz for a base training frequency of VR model (all 4 bands).
none - No processing (default)
bypass - This copies the missing frequencies from the input.
mirroring - This algorithm is more advanced than correlation. It uses the high frequencies from the input and mirrored instrumental's frequencies. More aggressive.
mirroring2 - This version of mirroring is optimized for better performance.
--high_end_process - In the old CLI VR, this argument restored the high frequencies of the output audio. It was intended for models with a narrow bandwidth - 16 kHz and below (the oldest “lowend” and “32000” ones, none more). But now in UVR5 GUI, High-end process is counterpart of mirroring.
(current 500MB models don’t have full 22kHz coverage, but 20kHz, so consider using mirroring instead or none if you want fuller spectrum)
- Be aware, that even for VR arch, the same rule for GPUs with less than 8GB VRAM applies (inb4 - Colab T4 has 15GB) - separations on 6GB VRAM have worse quality with the same parameters. In order to work around the issue, you can split your audio into specific parts (e.g. for all chorus, verses etc).