You can try this with Reaper if you just work in the main Biab program only and tired of dragging files over all the time.
This is just 1 Reaper script that works on any version of Biab frozen SGU/MGU, no modifications needed.
Import-frozen-SGU-MGU-realtracks-drums.zip

Just simply open a frozen SGU/MGU to instantly import the tracks into Reaper.
If you don't have the peak files already it will have to build them but once you have the reapeaks files it will be instant.
You can use Script: Create reapeaks in folder.lua

Some scripts I made for this ( see stash ):
Change selected realtrack source file type.lua : allows changing the file type to any other Reaper supported file format.
Create stems from selected realdrums stereo track.lua : allow you to create the exact same mutitrack drums from the stereo Drums track.
Change selected realtrack to fx.lua : allows change instrument from direct input to fx keeping the same riffs.
Change selected realtrack to direct input.lua : allows change instrument from fx to direct input keeping the same riffs.
Create reapeaks in folder.lua : batch create all the reapeaks for RealTracks & RealDrums so the tracks load in instantly.
ReaTrak Biab SGU MGU.. to regions ab.lua : import chords to regions.
Set 2 bar count-in.lua : set a 2 bar count-in offset




This will import new sections: Import single frozen track or section SGU MGU to selected track.lua (included with script above).

If your Biab song has tempo or time signature changes just drag in a midi/RC to Reaper first, this will also give you the chords as markers.
Some songs maybe using a different timebase track or you actually selected a different timebase:



you should get a prompt to ask the timebase of the track, so it's using a third timebase, the instrument is 40bpm but song is 120bpm so 3 is selected (see below)

*UPDATED 18 Dec 2023
This is set automatically, it will take out any glitches sustained notes or vocal to a varying tempo map by setting Item Properties > Stretch markers fade size: 0
Import-frozen-SGU-MGU-realtracks-drums.zip

Gotta try this. Does it actually implement a chord track, or are the chords in the regions just text labels?

You can import the midi chord markers from the Biab midi file as markers or regions or you can use ReaTrak-Biab-SGU-MGU..-to-regions-ab.zip .
It will just instantly transfer all tracks or a single track or section to the same track in Reaper without rendering and creating any new files.

If you batch convert your RT RD files with Reaper you can import the tracks in any format:

Thanks MusoCity. Awesome !

I have around 64,000 Rts with variations. After 32,000 analyzes in Reapeaks the script stops, it doesn't go any further, it displays Finish, but it bullshits me. No sleep program. When I restart it continues reading but no longer creates any Reapeak. So I must be around 50%. Weird right?

Create-reapeaks-in-selected-folder.zip
Try this it will do one selected folder at a time by selecting the audio file type.
So if you select a wma file it will create reapeaks for all wma files in that folder, or if wav or m4a or aif of flac etc..

The other script would take a very long time as it batch converts, not sure what went wrong in your pics will look more later.

Thanks for the folder version, but for several hundred folders it's unthinkable. In fact it's a memory problem it seems to me. Once the 16 gigabytes are full, it crashes. Too bad, the Repeaks will be done as I use them.

You can try and ask in the Reaper forum someone might have another script to do the same thing.
See how you go if not I can look at making one that will select so many folders to do at once so you can do in sections.
You can try and move a group of folders to RealTracks2 and Drum2 and just do them then them move back to RealTracks & Drums when done.

You can try these:
Updated: Create-reapeaks-in-folder.zip
Updated with reaper.PCM_Source_Destroy(src) so RAM don't build up.
Also: Create-reapeaks-in-subdirectories-for-media-type-(Win).zip this will do all sub directories in a single folder.

Wow! I can see a lot of good new options to streamline the interaction between Reaper and BiaB. There has been a significant leap in the last few months. Thank you @musocity for all the work done and the scripts. I am looking forward to finish a couple of music projects (not BB related) to take advantage of all the new posibilities.

In my opinion this link + a short explanation MUST be in a sticky post! It is a treasure!
https://stash.reaper.fm/u/ReaTrak

Thanks, I updated that:
https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)

This is using Biab and Open SGU in Reaper
I have a single frozen track I want to add to Reaper, I save the SGU



I open the SGU
I use Script: Import frozen SGU MGU realtracks drums.lua
this will insert a new track below the selected track and load the sections in:



New track added:




If I find a bad section I delete it:



I generate up that section in Biab on empty track, freeze that track only and save:



I use Script: Import single frozen track or section SGU MGU to selected track.lua
to add the new section to the selected track:



New track section inserted on selected track, you can adjust length to merge with next riff:



Using the BiabVST
Generate selected region, if it's half a bar you can easily manually adjust the riffs once added into the track,
you can adjust the snap resolution rather than just one current resolution of 1/32 in Biab,
best also to disable auto crossfade so notes or hits can ring out over other riffs:

You don't want the BiabVST messing around generating wavs so disable that:



To get the chord markers drag the C7 to the very start of an empty track and import markers,
same with Biab you can just drag a midi track from it to give the chord markers:

Import-frozen-SGU-MGU-realtracks-drums.zip
*UPDATED 21 Jan 2024
Set File > Project settings > Advanced > Item mix behavior > Items always mix
allows for item overlays like pushes to play at the same time as item under.
If SGU has Holds on the first track and first bar they will be set to SGU tempo.

*UPDATED 22 Jan 2024
Take markers offset to show instrument name.

New GUI script Set-SGU-MGU-single-frozen-track-or-section-to-import-to-selected-track-GUI.zip
This allows you to set the current SGU you are working on in Biab and instantly import any frozen track or section, so each time I generate a new bit or freeze a different track I Ctrl+ S Biab first then click the Import SGU in Reaper:

Import-frozen-SGU-MGU-realtracks-drums-tracks-GUI.zip
This gives the great song generation power of Biab with professional editing.
Use this "Browse" button to set the path of the frozen SGU/MGU, this can be the SGU you are currently working on in Biab.
"Reaload Tracks" button will load all the currently frozen tracks in the SGU.
"Selected" button will transfer the track instantly into the selected track.
"New" button will transfer the track instantly into a new track.
"Set" button will set Reaper bpm to same as SGU.
"Import Chords" button will import the current SGU chords as regions (make sure to Unfold and save first), it will set the bpm and time signature.
If you update or add new tracks in Biab, just freeze the track and save, then simply hit the "Reload Tracks" button to update the track list.

EDIT: If you don't have the peak files already it will have to build them but once you have the reapeaks files it will be instant.
You can use Script: Create reapeaks in folder.lua