annotate audio/sndfile.m @ 61:eff6bddf82e3 tip

Finally implemented perceptual brightness thing.

% sndfile - audio signal from audio file
%
% sndfile ::
%    path | cell { nonneg, nonneg, path } ~'file name or { start, end, path }'
%    options {
%       enc      :: {'mp3','aac','flac','ogg'};
%       channels :: natural/nan ~'desired number of channels';
%       rate     :: nonneg/nan ~'desired sampling rate';
%       bits     :: natural/16 ~'desired bits per sample';
%    }
% -> signal(C,R).
%
% This will use mp3file, aacfile or flacfile for those types of file, but jsndfile
% for anything else, including OGG files.
%
% If channels or rate are not nan, audio format will be converted to match.
% If either of them are nan, the corresponding value from the audio file will
% be left unchanged.

function s=sndfile(file,varargin)
	opts=options('enc','unknown',varargin{:});
	if iscell(file)
		s=taket(file{2}-file{1},dropt(file{1},sndfile(file{3})))
		return
	end
	string=sprintf('sndfile(''%s'')',file);
	if strcmp(opts.enc,'mp3') || endswith(file,'mp3') || endswith(file,'MP3')
		s=mp3file(file,'stringfn',@()string,opts); % Java version doesn't remove padding correctly
	elseif strcmp(opts.enc,'aac') || endswith(file,'m4a') 
		s=aacfile(file,'stringfn',@()string,opts);
	elseif strcmp(opts.enc,'flac') || endswith(file,'flac') 
		s=flacfile(file,'stringfn',@()string,opts);
	else
		s=jsndfile(file,varargin{:});
	end
end