STEP 5 Coding the Data

This is the last step in Data Preparation Stage. We need to convert the audio wav files to another format
called MFCC format.
We create a file containing a list of each source audio file and the name of the MFCC file it will be
converted to and use that file as a parameter to the HCopy command. This file is called the
codetr.scp.We use the HCopy tool to convert our wav files to MFCC format.
wav/S0001.wav mfcc/S0001.mfc wav/S0004.wav mfcc/S0004.mfc
wav/S0005.wav mfcc/S0005.mfc wav/S0008.wav mfcc/S0008.mfc

The HCopy command performs the conversion from wav format to MFCC. To do this, a configuration file
which specifies all the needed conversion parameters is required. Create a file called wav_config. (wav_config is the configuration file) It should contain following parameters

#Coding parameters
TARGETKIND = MFCC_0
TARGETRATE = 100000.0
SAVECOMPRESSED = T
SAVEWITHCRC = T
WINDOWSIZE = 250000.0
USEHAMMING = T
PREEMCOEF = 0.97
NUMCHANS = 26
CEPLIFTER = 22
NUMCEPS = 12
ENORMALISE = F

Now, Create a new directory MFCC in the working folder and execute the HCopy command from the working directory as follows
cmd> HCopy -T 1 -C wav_config -S codetr.scp
This result in the creation of a series of mfcc files corresponding to the files listed in your codetrain.scp script.