can't say i've noticed a problem - i'm just curious. If i generate a piano then change key and regenerate, just like a live pianist i'd expect the piano to move up a key and play different notes - same part just higher. so C to G would simply mean different keys on the keyboard.

but a guitar is different. if i move from C to G, the different chord shapes have different open strings and some runs are more natural in one key rather than another. I play different patterns in C to G or D.

does a BIAB realtrack take that into account or does it just 'capo up' - same note but higher? and if I want to transpose down a key (is that option still available?) would it play a bass note that is not possible on a 6 string guitar?

the reason i ask is that working in RB i now have a song i want to change the key for - its all audio tracks. should i just change key and let the program pitch transpose everything or should i regenerate the guitar in the new key and get a guitar part that a guitarist would have played in different cowboy chords?

this is not a complaint, or a wish list item - i'm just curious and of course i could change key and regenerate (or not!)and listen.

i'm a guitarist so any comments from other guitarists or even 'proper musicians'?

Much of this is proprietary info which PGMusic has not shared details. But, I think you are assuming BIAB is smarter than it is. All RTs are recordings performed in a style, described by the title of the realtrack used and at a tempo which is set within a range of +/- ~20 bpm around what was recorded and then adjusted using tempo stretching to the tempo you select. Same for pitch. The pitch is based on the nearest match to what was recorded and then pitch-shifted to the key you select. If you change tempo or key BIAB will repeat the process during the regeneration to match the new setting. There is no ability to select chord voicings. That is my best guess...

I agree with Dan. My understanding is that the RealTracks artists recorded multiple music phrasings using different keys. The program finds the best match and then adjusts by stretching a minimal amount as necessary. Naturally, this is only a simplistic conceptual view, and the detail to successfully achieve this will be quite complex.

<< its all audio tracks. should i just change key and let the program pitch transpose everything or should I regenerate the guitar in the new key and get a guitar part that a guitarist would have played in different cowboy chords? >>

I suggest to save the track prior to making any changes. If the key change doesn't work to your satisfaction or if you revert back to the original key, you can also recover the exact phrasing of the track by importing the saved audio file regardless if you regenerate the tracks.

Import a copy of that saved audio file and transpose it to the new key and retain the exact phrasing of the original file.

If you do that (what Charlie is suggesting) I think you will only be satisfied with the audio quality if the pitch shift is one full step maximum.

Bob Calver.
HOW MOST MUSIC/MULTITRACK SOFTWARE WORKS.
(filling gas tanks lol.)
i'll try and use an example. (i'm just a user.)
1. the first concept to understand is real time IS AN ILLUSION.
2. whats really happening behind the scenes is small data buffers are being filled IN ADVANCE OF THEM BEING NEEDED.
3. lets use gas tanks as an example. if you let a gas tank get empty car wont work.
4. now imagine a traditional multitrack software program. 24 traks youve set up.
so we have to fill 24 data buffers. (data buffers are small.) before they are needed.
now imagine 24 gas tanks and one gas jockey , its gonna take longer than if we use more gas jockeys to fill gas tanks. so to fill up faster we need more gas jockeys.
thus the more traks , the more data buffers needed.
5. its important to understand why systems "hiccup". it doesnt happen as often these days because computer architectures have become faster. one reason to use ssd's is no disc drive rotational latency.
one reason to keep windows on its own drive, and have a second drive dedicated to recording is windows wont interrupt to do its own thing.
6. one reason that "hiccups" can occur is the gas tanks (data buffers) arent being filled on time , (the gas jockey is takeing a break lol.)
possibly another procedure has interrupted the filling of gas tanks (data buffers.). this is why hiccups occur on low power machines.
they cant handle the load, cos a user has tried to use a boatload of traks and plug ins.
too many data buffers/gas tanks to fill. not enough resources.
7. given the above (and to quote "sheldon" on big bang lol and spock. its only logical.)
there is an added wrinkle with accompaniement software like biab. over traditional multitrack software.
there is added functionality to be attended to in playing back the users chosen instruments (eg guitars) and chords and other settings.
biab is unique in this regard. in summary added assembly behind the scenes is takeing place in addition to filling gas tanks/data buffers.
("ya mean i gotta build the gas tank fast AS WELL ? lol.)

but STILL real time is an illusion.
STILL data buffers(gas tanks) are being filled etc etc.
its all to do with data buffer assembly.

apologies if i didnt explain too well.

best.
oldmuso

What a great question... I have often wondered how BIAB deals with RT guitar transpositions.

Bob.
(ok had my supper. lol. i'll share some dsp tricks/addressing/solving "burbles"/"artifacts" in RT's.
when doing extreme things to them.)
first some background.
1. any audio track is just a series of numbers. (samples.)
thats what a waveform is. only numbers.
2. so everything in dsp is math manipulation of numbers.
whatever biab (or any other software like a plug in ) does is just math. includeing transposing.
3. so lets take a guitar trak. RT. its just a series of numbers.
the KEY is how to minimise "burbles" created by math dsp manipulation.
we look at the tempo of a style or RT , and its tempting to think "no i shouldnt stray much from that tempo" when we are building an original song.
4. how do we mitigate "burbles" ? ive actually utilised on some original songs instruments in other genres that supposidly should not work cos its way off from the genre i am useing and/or tempo in the current song i'm working on.
thus i'm an experimenter. i transpose too.
for example this RT rhythm guitar is recommended at
120 bpm , but my song is 165 bpm. lets see if it "burbles" at 165 bpm or i get artifacts etc.
5. what ive found is some artifacts/burbles are noticeable, but some might not be.
if its really bad i normally move on.
BUT some can be rescued by being "artfull".
what i do is pass that slightly "burbly" or "artifacted" track through a guitar amp plug in.
its really hit and miss. for example in my daw i have some reaper guitar amp emulations , (tweeds/bassman/marshall etc etc.)and i also use an external freebie guitar amp software.
so i export the guitar RT to my daw. then try various manipulations useing the dsp guitar plug in. sometimes it works, sometimes not. its experimental.
as is transposing manually.
and heres another trick. i will play my guitar along with the burbly RT guiitar, and merge both together into the guitar amp plug in, maybe doing some judicious editing
in the process.
6. there is yet another trick to try with a artifacted/burbly guitar RT.
useing a noise reduction plug in. eg reaper reafir. zoom into the guitar RT , and hilite the burble/artifact as a noise print. then apply that noise print to the whole artifacted
guitar RT trak in your daw, and see the effect after passing the new trak once again through a guitar amp plug in software.

as i said, its all experimentation. sometimes works sometimes dont.
but ive rescued some way out of range RT guitar traks useing above methods.

i remember in previous versions of biab was a screen that said something like not right genre.
i used to disregard that constantly,lol. and, as a result got some happy accidents. wow a slow cello in a faster rock song,
how can that be . its all manipulation.

hope this helps with RT useage.

oldmuso.

thanks everyone so apart from the advice on artifacts etc, no one really knows although videotrack suggests that realtracks are recorded in different keys.

most sensible choice for a guitar part is C A G E D. so if they are, then any key can be played in with a capo no more than two frets up for the key of B and one fret for the rest. i know BIAB doesn't use capos but the principle is the same - shapes and notes moved a semi tone or so which ties in with Matt's point about pitch shift of no more than one tone.
maybe PG staff can advise, as i say, its not a complaint or a wish list item, just a curious enquiry

Bob.
goodness mate (give my "luv" to "blighty" lol.)
if you go into the biab sub directories where the RT's reside, and play along with the ACOUSTIC RT's ON THEIR OWN in win media player with your acoustic.
youll find it very interesting. try several acoustic guitar RT's. see my reply to videotrack below.

videotrack.
try this WITHOUT DISTURBING or DELETING ANYTHING IN THE BB DIR.
navigate BB>>realtraks>>acoustic guitar (lots of them.).
NOTICE A ACOUSTIC GUITAR TRACK HAS TEMPO IN ITS FILE NAME ?.
in fact each RT has tempo in its file name.

now clik on the file header with tempo and youll see a file that windows media will play.
play along with it , on an acoustic guitar (or electric) with the chords being played.
try several RT's playing along with them in windows media player. at different tempos.

now if one reads in biab help how to create a USER REAL TRACK.
biab is asking for SAMPLE(s).
so what can we conclude ?
1. tempo is a critical factor.
2. how much a user strays from original tempo is a critical factor.
think of any engineering project, say an airplane wing. the product is built within certain tolerances, but go outside those tolerances, and odd things will happen.
ie wing falls apart. same with audio samples.
3. in the biab docs youll see mention of zplane/elastique technology. read up on this on the net.

if you think about it, if pg built RT's for every eventuality , the bb dir would be a massive data base.
absolutely gigundous. therefore biab must be "reconstituting" instrument samples in the bb software.
useing zplane etc etc.
the only conclusion one can make.
otherwise in the audiophile edition, the data base size would be off the charts/unmaneageable i reckon.
and heres where the challenge for pg comes in trying to keep the loyal user base happy.
lets say pg goes to what i REALLY WANT which is a total orchestra in a box.
think of the challenge of database size.
this is why orchestral sample libs are so big, and why they can swamp a low power pc. the challenge once again is keeping users with poor performing pc's happy AND power i9 users happy.

i respect pg for this aspect. not easy. which is why i would ask pg users to support a feature (see wishlist) i asked for. ie. an early warning system in biab (and RB and powertraks)
before a users pc (or mac) gets overloaded and crashes possibly.

any more tech aspects pg will have to comment on.

best.
muso.

Yes, obviously tempo matters. That's why when discussing that multiple recordings were probably used I also mentioned: "Naturally, this is only a simplistic conceptual view". We are all aware that Tempo and Pitch can only be moved a specific amount without introducing unwanted artifacts.