ECMC pvc example  twarp2 actually is a linear mix of 2 soundfiles,
created by ECMC PVC example files "twarp2-1" and then "twarp2-2".
Like example "twarp1," both resyntheses use the analysis file
of "voicetest" ("post-processed by various") previously created with
pvanalysis example "pvanalysis.voicetest", but create different function
files to control the "playback speed" (rate) at which this analysis
is read, and use only the first 1.05 seconds ("post-processed by ...")
# of the 1.46 analysis file

 -  -  -  -
In example "twarp2-1," heard first, the analysis is read forwards
from beginning to end, but is read very slowly at first, then
rapidly speeds up:
    gen4 -L1000 0 0 4 1 1.05  > $SFDIR/timepointfunc
 (The values in the table begin at 0 and end at 1, but increase
in value slowly at first, and very rapidly at the end.)
This function is applied to the following resynthesis parameters:

time_point=/$SFDIR/timepointfunc      # int, float or FUNC
lower_time_boundary=$SFDIR/timepointfunc # int, float or FUNC
upper_time_boundary=$SFDIR/timepointfunc # int, float or FUNC

 -  -  -  -
By contrast, in example "twarp2-2," which follows in soundflie
/sflib/x/twarp2 after a second of silence, a different timepoint
function causes the analysis to be read rapidly at the beginning
of the resynthesis, but then to slow down dramatically:
 gen4 -L1000 0 0 -4 1 1.05  > $SFDIR/timepointfunc
 -  -  - 
To see the source files for "twarp2-1" or "twarp2-2" type
   pvcex  twarp2-1
   pvcex  twarp2-2
