Resampling audio data

Method1:

Using ch_wav  command

Example: Converting 16 Khz wave file into 8 Khz

ch_wave   -f    16000   -F    8000 -o   wav_8KHz/text001.wav     ../wav_16KHz/text001.wav

Method2:

Using sox command

sox input.wav -r 44000 output.wav resample

Here 44000 is the sampling rate of output file

Example: Converting 16 Khz wave file into 8 Khz

sox   text0001.wav   -r    8000   wav_8KHz/text001.wav   resample

Resampling all files of a directory

write following code in a file suppose down_sample.pl
chomp(@ARGV = <STDIN>) unless @ARGV;
for ( @ARGV )
{
  $was = $_;
  print "was=$was";
  #print "op =$op";

   
 
 $now="./output/".$was;
print "now1=$now\n";
   # @args= ( "ch_wave", "-f", "48000", "-F", "16000", "-o", "$now", "$was");
 @args= ( "sox", "$was", "-r", "16000", "$now", "resample" );
  
                            system(@args);


}

Suppose you are having 48 Khz wav files i directory wav_48khz:

1. Copy the down_sample.pl file having above code into wav_48khz directory

2. Create directory output inside wav_48khz directory

3. Open terminal and go to the wav_48khz directory

4. run following command

    perl down_sample.pl *.wav

5. 16 Khz wav files will be inside output directory

7. You may use either sox or ch_wav command. Some times ch_wav command does not recognise wave files then we should use sox.