/usr/share/doc/octave-gdf/examples/gdf_resample.m is in octave-gdf 0.1.2-2build3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 | function gdf_resample( fs_new, inputfile, outputfile, datatype )
% 1. load gdf file
[signals, header, events] = gdf_reader( inputfile, 'multiratesignals', 'single', 'dataorientation', 'row' );
num_channels = length( signals );
% 2. resample
for c = 1 : num_channels
fs_old = header.signals(c).sampling_rate;
div = gcd( fs_new, fs_old );
P = fs_new / div;
Q = fs_old /div;
signals{c} = resample( signals{c}, P, Q );
header.signals(c).sampling_rate = fs_new;
% better adjust physmin and physmax, as the signal may locally
% increase in amplitude due to the anti aliasing filter.
header.signals(c).physmin = min(signals{c});
header.signals(c).physmax = max(signals{c});
if exist( 'datatype', 'var' )
header.signals(c).datatype = datatype;
switch datatype
case 1, header.signals(c).digmin=-128; header.signals(c).digmax=127;
case 2, header.signals(c).digmin=0; header.signals(c).digmax=256;
case 3, header.signals(c).digmin=-32768; header.signals(c).digmax=32767;
case 4, header.signals(c).digmin=0; header.signals(c).digmax=65536;
case 5, header.signals(c).digmin=-2147483648; header.signals(c).digmax=2147483647;
case 6, header.signals(c).digmin=0; header.signals(c).digmax=4294967295;
case 7, header.signals(c).digmin=-9223372036854775808; header.signals(c).digmax=9223372036854775807;
case 8, header.signals(c).digmin=0; header.signals(c).digmax=18446744073709551615;
case 16, header.signals(c).digmin=-1; header.signals(c).digmax=1;
case 17, header.signals(c).digmin=-1; header.signals(c).digmax=1;
end
end
end
% 3. fix event positions
if events.mode == 3
events.duration = events.duration * double(fs_new / events.sample_rate);
end
events.position = events.position * double(fs_new / events.sample_rate);
events.sample_rate = fs_new;
% 4. save new gdf
handle = gdf_writer( 'init' );
for c = 1 : num_channels
gdf_writer( 'createsignal', handle, c );
end
gdf_writer( 'setheader', handle, header );
gdf_writer( 'recordduration', handle, 0 ); % automatic record duration
gdf_writer( 'eventconfig', handle, events.mode, events.sample_rate );
gdf_writer( 'open', handle, outputfile );
% for c = 1 : num_channels
% gdf_writer( 'blitsamples', handle, c, signals{c} );
% end
chunksize = 512;
num_chunks = ceil(size(signals{1},2) / chunksize);
for d = 1 : num_chunks
for c = 1 : num_channels
start = (d-1)*chunksize + 1;
ende = min( d*chunksize, size(signals{1},2) );
gdf_writer( 'blitsamples', handle, c, signals{c}(start:ende) );
end
end
if events.mode == 1
for e = 1 : length( events.position )
gdf_writer( 'mode1ev', handle, events.position(e), events.event_code(e) );
end
elseif events.mode == 3
for e = 1 : length( events.position )
gdf_writer( 'mode3ev', handle, events.position(e), events.event_code(e), events.channel(e), events.duration(e) );
end
end
gdf_writer( 'close', handle );
gdf_writer( 'clear', handle );
end
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