Andres,

With respect to nsamp, I'd suggest adding the relevent equivalent to ftlen -
just before the example:

As of Csound version 3.53, ftlen works with deferred function tables (see
GEN01).

I've a number of suggestions for the proposed loscil docs. When I'm finished
all the current testing, I'll send them on. Right now the holdup is trying
to find if WAV files work the same as AIFF (with loscil).

Do perhaps you know of a WAV sample with internal loop info I could use for
testing?

Art Hunkins

----- Original Message ----- 
From: "Andres Cabrera" 
To: "Art Hunkins" 
Sent: Monday, May 29, 2006 11:15 PM
Subject: Re: [Csnd] Help Needed: loscil


Thanks Istvan for the additions.

On Mon, 2006-05-29 at 13:16 -0400, Art Hunkins wrote:
> Thanks, Istvan, for both of these updates. They take care of all my
> immediate needs. (It also would be wonderful if someone could update and
> clarify the documentation for loscil, loscil3 and nsamp. I'd be happy to
> review any updates if that would help.)
I've added the information on looping the whole file in cvs, this
functionality and the updated manual should be available in the upcoming
5.02 release. Art, do you think the entries for nsamp or ftlen require
any modifications?

> I've been trying further to investigate whether loscil works correctly
with
> samples that contain their own looping information. Either 1) it is not
> working; or 2) the distribution doesn't contain any such samples, so you
> can't know whether the feature works or not.
libsndfile only recently started supporting loop points, so even though
past versions of csound could read looping points, the current one
depends on the ability of libsndfile to do so. It is very likely that
your release contains an older version of libsndfile which doesn't
support loop points.


Cheers,
Andrés

The manual entry now reads (any suggestions welcome):


loscil
loscil — Read sampled sound from a table.



Description
Read sampled sound (mono or stereo) from a table, with optional sustain
and release looping.



Syntax
ares [,ar2] loscil xamp, kcps, ifn [, ibas] [, imod1] [, ibeg1] [, iend1] [,
imod2] [, ibeg2] [, iend2]
Initialization
ifn -- function table number, typically denoting an AIFF sampled sound
segment with prescribed looping points. The source file may be mono or
stereo.

ibas (optional) -- base frequency in Hz of the recorded sound. This
optionally overrides the frequency given in the AIFF file, but is
required if the file did not contain one. The default value is 261.626
Hz, i.e. middle C. (New in Csound 4.03).

imod1, imod2 (optional, default=-1) -- play modes for the sustain and
release loops. A value of 1 denotes normal looping, 2 denotes forward &
backward looping, 0 denotes no looping. The default value (-1) will
defer to the mode and the looping points given in the source file.

ibeg1, iend1, ibeg2, iend2 (optional, dependent on mod1, mod2) -- begin
and end points of the sustain and release loops. These are measured in
sample frames from the beginning of the file, so will look the same
whether the sound segment is monaural or stereo. If no loop points are
specified, and a looping mode (imod1, imod2) is given, the file will be
looped for the whole length.



Performance
ar1, ar2 -- the output at audio-rate. There is just ar1 for mono output.
However, there is both ar1 and ar2 for stereo output.

xamp -- the amplitude of the output signal.

kcps -- the frequency of the output signal in cycles per second.

loscil samples the ftable audio at a-rate determined by kcps, then
multiplies the result by xamp. The sampling increment for kcps is
dependent on the table's base-note frequency ibas, and is automatically
adjusted if the orchestra sr value differs from that at which the source
was recorded. In this unit, ftable is always sampled with
interpolation.

If sampling reaches the sustain loop endpoint and looping is in effect,
the point of sampling will be modified and loscil will continue reading
from within that loop segment. Once the instrument has received a
turnoff signal (from the score or from a MIDI noteoff event), the next
sustain endpoint encountered will be ignored and sampling will continue
towards the release loop end-point, or towards the last sample
(henceforth to zeros).

loscil is the basic unit for building a sampling synthesizer. Given a
sufficient set of recorded piano tones, for example, this unit can
resample them to simulate the missing tones. Locating the sound source
nearest a desired pitch can be done via table lookup. Once a sampling
instrument has begun, its turnoff point may be unpredictable and require
an external release envelope; this is often done by gating the sampled
audio with linenr, which will extend the duration of a turned-off
instrument by a specific period while it implements a decay.

If you want to loop the whole file, specify a looping mode with imod1 do
not enter any values for ibeg and iend.

               [Note]
Note
This is mono loscil:

a1 loscil 10000, 1, 1

...and this is stereo loscil:

a1, a2 loscil 10000, 1, 1

Examples
Here is an example of the loscil opcode. It uses the files loscil.orc,
loscil.sco, and beats.aiff.

Example 210. Example of the loscil opcode.

/* loscil.orc */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1

; Instrument #1.
instr 1
   kamp = 30000
   ; If you don't know the frequency of your audio file,
   ; set both the kcps and ibas parameters equal to 1.
   kcps = 1
   ifn = 1
   ibas = 1

   a1 loscil kamp, kcps, ifn, ibas
   out a1
endin
/* loscil.orc */


/* loscil.sco */
; Table #1: an audio file.
f 1 0 262144 1 "beats.aiff" 0 4 0

; Play Instrument #1 for 6 seconds.
; This will loop the audio file several times.
i 1 0 6
e
/* loscil.sco */


See Also
loscil3



Credits
Note about the mono/stereo difference was contributed by Rasmus Ekman.

Example written by Kevin Conder.