Running Bjontegaard function: error line 30?

Dear Support Community,

I'm trying to understand the Bjontegaard function as coded by Giuseppe Valenzise without success.

Running the function defining code generates the an error at line 30 (highlighted in bold and italics in code below).

And running function after defining it with Giuseppe Valenzise sample values returned errros in the code execution at line 13.

Has anyone been able to test/use this code?

function avg_diff = bjontegaard(R1,PSNR1,R2,PSNR2,mode)

%BJONTEGAARD Bjontegaard metric calculation

% Bjontegaard's metric allows to compute the average gain in PSNR or the

% average per cent saving in bitrate between two rate-distortion

% curves [1].

% Differently from the avsnr software package or VCEG Excel [2] plugin this

% tool enables Bjontegaard's metric computation also with more than 4 RD

% points.

%

% R1,PSNR1 - RD points for curve 1

% R2,PSNR2 - RD points for curve 2

% mode -

% 'dsnr' - average PSNR difference

% 'rate' - percentage of bitrate saving between data set 1 and

% data set 2

%

% avg_diff - the calculated Bjontegaard metric ('dsnr' or 'rate')

%

% (c) 2010 Giuseppe Valenzise

%

% References:

%

% [1] G. Bjontegaard, Calculation of average PSNR differences between

% RD-curves (VCEG-M33)

% [2] S. Pateux, J. Jung, An excel add-in for computing Bjontegaard metric and

% its evolution

% convert rates in logarithmic units

lR1 = log(R1); % line 30

lR2 = log(R2);

switch lower(mode)

case 'dsnr'

% PSNR method

p1 = polyfit(lR1,PSNR1,3);

p2 = polyfit(lR2,PSNR2,3);

% integration interval

min_int = min([lR1; lR2]);

max_int = max([lR1; lR2]);

% find integral

p_int1 = polyint(p1);

p_int2 = polyint(p2);

int1 = polyval(p_int1, max_int) - polyval(p_int1, min_int);

int2 = polyval(p_int2, max_int) - polyval(p_int2, min_int);

% find avg diff

avg_diff = (int2-int1)/(max_int-min_int);

case 'rate'

% rate method

p1 = polyfit(PSNR1,lR1,3);

p2 = polyfit(PSNR2,lR2,3);

% integration interval

min_int = min([PSNR1; PSNR2]);

max_int = max([PSNR1; PSNR2]);

% find integral

p_int1 = polyint(p1);

p_int2 = polyint(p2);

int1 = polyval(p_int1, max_int) - polyval(p_int1, min_int);

int2 = polyval(p_int2, max_int) - polyval(p_int2, min_int);

% find avg diff

avg_exp_diff = (int2-int1)/(max_int-min_int);

avg_diff = (exp(avg_exp_diff)-1)*100;

end