Help looping through mat files with sound function

I have several *.mat sound files (e.g., tunes_audio.mat) that I have load into my Matlab workspace using the following code:

s = what;
matfiles=s.mat;
for a=1:numel(matfiles)
    load(char(matfiles(a)))
end

I would now like to play each of these files using the sound function. Simply typing sound(tunes_audio) works just fine. But I want to loop through all the loaded files and play them one at a time without having to type each name into the script. I have tried sound(char(matfiles{1}(1:end-4))) but I get an error message saying "Audio data must be real and floating point." Would somebody please help me loop through and read each loaded *.mat file?

Thank you in advance!

Answer 1

[Walter Roberson]

dinfo = dir('*.mat');
for K = 1 : length(dinfo)
   thisfile = dinfo(K).name;
   datastruct = load(thisfile);
   fn = fieldnames(datastruct);
   data = datastruct.(fn{1});
   fprintf('now playing: %s\n', thisfile);
   sound(data);
 end

[Daulton_Benesuave]

Thanks. I tried your solution but still received the same error

Error using sound (line 33) Audio data must be real and floating point.

[Walter Roberson]

dinfo = dir('*.mat');
for K = 1 : length(dinfo)
   thisfile = dinfo(K).name;
   datastruct = load(thisfile);
   fn = fieldnames(datastruct);
   data = datastruct.(fn{1});
   bad_data = true;
   if ~isfloat(data)
     fprintf('Ooo... file %s variable %s is not floating point, is %s skipping it\n', thisfile, fn{1}, class(data));
   elseif ~isreal(data)
     fprintf('Ooo... file %s variable %s is floating point but complex, skipping it\n', thisfile, fn{1});
   elseif isempty(data)
     fprintf('Ooo... file %s variable %s is real floating point but empty, skipping it\n', thisfile, fn{1});
   else
     bad_data = false;
  end
  if bad_data
     for J = 2 : length(fn)
       data2 = datastruct.(fn{J});
       if ~isempty(data2) & isfloat(data2) & isreal(data2)
         fprintf('But file %s variable %s looks okay, perhaps you want to load it.\n', thisfile, fn{J});
       end
     end
   else
     fprintf('now playing: %s variable %s\n', thisfile, fn{1});
     sound(data);
   end
 end

[Daulton_Benesuave]

Walter,

Than you for trying to help. I ran the code and below is the output.

Ooo... file mule_audio.mat variable ans is not floating point, is audioplayer skipping it
But file mule_audio.mat variable mule_audio looks okay, perhaps you want to load it.

I am afraid I do not know enough about Matlab to decipher the results and hence I cannot get the files to play ...

[Walter Roberson]

dinfo = dir('*.mat');
for K = 1 : length(dinfo)
   thisfile = dinfo(K).name;
   datastruct = load(thisfile);
   fn = fieldnames(datastruct);
   mask = ismember(fn, {'ans'}) );
   if any(mask)
     fprintf('Skipping file "%s" variable "ans"\n', thisfile);
     fn(mask) = [];
   end
   data = datastruct.(fn{1});
   bad_data = true;
   if ~isfloat(data)
     fprintf('Ooo... file "%s" variable "%s" is not floating point, is "%s" skipping it\n', thisfile, fn{1}, class(data));
   elseif ~isreal(data)
     fprintf('Ooo... file "%s" variable "%s" is floating point but complex, skipping it\n', thisfile, fn{1});
   elseif isempty(data)
     fprintf('Ooo... file "%s" variable "%s" is real floating point but empty, skipping it\n', thisfile, fn{1});
   else
     bad_data = false;
  end
  if bad_data
     for J = 2 : length(fn)
       data2 = datastruct.(fn{J});
       if ~isempty(data2) & isfloat(data2) & isreal(data2)
         fprintf('But file "%s" variable "%s" looks okay, perhaps you want to load it.\n', thisfile, fn{J});
       end
     end
   else
     fprintf('now playing: file "%s" variable "%s"\n', thisfile, fn{1});
     sound(data);
   end
 end

[Daulton_Benesuave]

Thank you. The sound does now play but it's extremely distorted.

[Walter Roberson]

You probably need to specify a sampling frequency in the sound() call, but you have not given us any way to know what the appropriate frequency would be.