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<CsoundSynthesizer>
<CsOptions>
-odac
</CsOptions>
<CsInstruments>
/*
EXAMPLE 7
A rudimentary pitch tracking concatenative resynthesizer as such
This creates a sqlite database in memory, and then uses the opcode getpitches to scan through a
sound file in non-realtime, storing detected pitches and the relevant offset time of the pitch in
the database. The example file is a descending violin glissando.
When done, the instrument "playmatches" is scheduled twice which plays an oscillator varying in pitch,
which is pitch tracked and the nearest frequency is found in the database, prompting the "segment"
instrument to be scheduled with the relevant offset.
1. for 20s in which nearest matches are played only if the detected pitch has changed outside of a threshold
2. as above but with matches played continuously
The result is that the violin segments picked should moreorless match what the oscillator is doing.
*/
sr = 44100
kr = 4410
nchnls = 2
0dbfs = 1
; create an in-memory sqlite database and create a table
gidb dbconnect "sqlite", ":memory:"
dbexec gidb, "CREATE TABLE pitches (time REAL, cps REAL)"
; file of ascending piano pitches
gSfile = "sounds/violin.wav"
gifn ftgen 0, 0, 0, 1, gSfile, 0, 0, 0
; detect pitches and insert time/cps to database given a filename, in non-realtime
opcode getpitches, 0, S
Sfile xin
ktimek timeinstk
ktime timeinsts
klast init -1
kcount init 0
; run in the first single k-rate cycle
if (ktimek == 0) then
; get file length in k-cycles
ilen filelen Sfile
kcycles = ilen * kr
loop:
; read file and track pitch
ain diskin2 Sfile, 1
;ain butterbp ain, 500, 250
koct, kamp pitch ain, 0.01, 6, 12, 6, 12, 60
; only take action if pitch has changed
kchanged changed2 koct
if (kchanged == 1) then
; only store if cps is reasonably different from the last value
kcps = cpsoct(koct)
if (1==1) then
; insert to database: the dbexec_kb opcode is k-rate but blocking/synchronous.
; simpler to use for the non-realtime operation as regular _k opcodes are threaded/asynchronous
ktime = kcount / kr
Squery sprintfk "INSERT INTO pitches (time, cps) VALUES (%f, %f)", ktime, kcps
dbexec_kb gidb, Squery
klast = kcps
endif
endif
loop_lt kcount, 1, kcycles, loop
endif
endop
; begin the example: find pitches and then schedule the next step
instr start_example
getpitches gSfile
schedkwhen 1, 0, 0, "playmatches", 0, 20, 0
schedkwhen 1, 0, 0, "playmatches", 20, 20, 1
turnoff
endin
; pitch follow a descending oscillator and attempt to find a similar cps in the database, then schedule segment accordingly
instr playmatches
kdone init 0 ; for when the select query is done
klast init 0 ; last pitch played, in order to avoid repeats
; oscillator
k1 linseg 400, p3, 200
ktime linseg 0.001, p3, 2
k2 oscil k1, ktime
ain oscil 1, abs(k2)+550, 1
; track it
koct, kamp pitch ain, 0.01, 5, 10, 6, 12
; only take action when the tracked pitch has changed
kchanged changed2 koct
if (kchanged == 1) then
; (very roughly) get a near frequency match from the database
kcps = cpsoct(koct)
; fairly nasty looking query for obtaining the nearest value
SquerySource = {{
SELECT time FROM (
SELECT time, cps FROM (
SELECT time, cps FROM pitches WHERE cps >= %f ORDER BY cps ASC LIMIT 1
)
UNION SELECT time, cps FROM (
SELECT time, cps FROM pitches WHERE cps < %f ORDER BY cps DESC LIMIT 1
)
) x ORDER BY ABS(cps - %f) ASC LIMIT 1
}}
Squery sprintfk SquerySource, kcps, kcps, kcps
kdone, kpos dbscalar_k gidb, Squery, kchanged
;schedule the notes
if (p4 == 1) then
schedkwhen kdone, 0, 0, "segment", 0, 0.2, kpos
else
if (kpos < klast*0.8 || kpos > klast*1.2) then
schedkwhen kdone, 0, 0, "segment", 0, 0.2, kpos
klast = kpos
endif
endif
endif
; uncomment to hear the oscillator as well as pitch matched output
;outs ain*0.01, ain*0.01
endin
; play part of the sound file given a skip time with a basic envelope
instr segment
il = ftlen(gifn)
isec = il/sr
ist = sr*p4
icps = 1/isec
aphs phasor icps
andx = aphs * il
aout tablei andx+ist, gifn
kamp linseg 0, p3*0.3, 1, p3*0.4, 1, p3*0.3, 0
outs aout*0.1*kamp, aout*0.1*kamp
endin
</CsInstruments>
<CsScore>
f1 0 16384 10 1 0 0.3 0 0.2 0 0.14 0 .111 ; square wave
i"start_example" 0 1
</CsScore>
</CsoundSynthesizer>
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