pvsbufread — This opcode reads a circular buffer of f-signals (streaming PV signals).
This opcode sets up and writes to a circular buffer of length ilen (secs), giving a handle for the buffer and a time pointer, which holds the current write position (also in seconds). It can be used with one or more pvsbufread opcodes. Writing is circular, wrapping around at the end of the buffer.
ilo, ihi -- set the lowest and highest freqs to be read from the buffer (defaults to 0, Nyquist).
fsig -- output pv stream
ktime -- time position of reading pointer (in secs).
khandle -- handle identifying the buffer to be read. When using k-rate handles, it is important to initialise the k-rate variable to a given existing handle. When changing buffers, fsig buffers need to be compatible (same fsig format).
pvsbufread reads f-signals from a buffer created by
With this opcode and pvsbuffer, it is possible to, among other things:
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It is important that the handle value passed to pvsbufread is valid and was created by pvsbuffer. Csound will crash with invalid handles. |
Here is an example of the pvsbufread opcode. It does 'brassage' by switching between two buffers.
Example 468. Example of the pvsbufread opcode
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
fsig1 pvsanal asig1,1024,256,1024,1 fsig2 pvsanal asig2,1024,256,1024,1 ibuf1,kt1 pvsbuffer fsig1, 10 ; 10-sec buf with fsig1 ibuf2,kt2 pvsbuffer fsig2, 7 ; 7-sec buf with fsig2 khan init ibuf1 ; initialise handle to buf1 if ktrig > 0 then ; switch buffers according to trigger khan = ibuf2 else khan = ibuf1 endif fsb pvsbufread kt1, khan ; read buffer
Here is an example of the pvsbufread opcode. It uses the file pvsbufread.csd.
Example 469. Example of the pvsbufread opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<CsoundSynthesizer> <CsOptions> ; Select audio/midi flags here according to platform ; Audio out Audio in -odac ;;;RT audio I/O ; For Non-realtime ouput leave only the line below: ; -o pvsbufread.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 16 nchnls = 1 0dbfs = 1 ;; example written by joachim heintz 2009 opcode FileToPvsBuf, iik, Siiii ;;writes an audio file at the first k-cycle to a fft-buffer (via pvsbuffer) Sfile, ifftsize, ioverlap, iwinsize, iwinshape xin ktimek timeinstk if ktimek == 1 then ilen filelen Sfile kcycles = ilen * kr; number of k-cycles to write the fft-buffer kcount init 0 loop: ain soundin Sfile fftin pvsanal ain, ifftsize, ioverlap, iwinsize, iwinshape ibuf, ktim pvsbuffer fftin, ilen + (ifftsize / sr) loop_lt kcount, 1, kcycles, loop xout ibuf, ilen, ktim endif endop instr 1 ifftsize = 1024 ioverlap = ifftsize / 4 iwinsize = ifftsize iwinshape = 1; von-Hann window ibuffer, ilen, k0 FileToPvsBuf "fox.wav", ifftsize, ioverlap, iwinsize, iwinshape ktmpnt linseg ilen, p3, 0; reads the buffer backwards in p3 seconds fread pvsbufread ktmpnt, ibuffer aout pvsynth fread out aout endin </CsInstruments> <CsScore> i 1 0 5 e </CsScore> </CsoundSynthesizer>