Getting the data

You need to order the NIST SRE databases (Fisher, Switchboard, and Mixer):

http://www.ldc.upenn.edu/Catalog/CatalogEntry.jsp?catalogId=LDC2013S03

Please follow the instructions and the evaluation plan given by NIST:

http://www.nist.gov/itl/iad/mig/sre12.cfm

Depending on the release year, the data may need to be flatten and reorganized. Please, follow the file structure as appearing when running:

$ bin/bob_dbmanage.py nist_sre12 dumplist

For this purpose, you will need the utilities provided by NIST with the database, as well as sox.

Decompressing the data and splitting the audio channels

The data provided by NIST are compressed in a non-standard format. NIST supplies a binary called w_decode to perform the decompression. Therefore, you should decompress all the files using the following command (where NIST_FOLDER/bin is the one containing the w_decode utility:

$ NIST_FOLDER/bin/w_decode -o pcm $compressedfile $decompressedfile

Several files are in stereo and hence contain two audio channels. These files needs to be split using a script similar to the following one:

$ decompressedfileStereo=`basename $decompressedfile .sph`
$ num=`soxi $decompressedfile | grep Channels | cut -c 18`
$ echo $num
$ if [ $num -eq 2 ]
$ then # File is stereo
$   echo sox $decompressedfile -c 1 $outputDir/${decompressedfileStereo}-a.sph mixer -l
$   sox $decompressedfile -c 1 $outputDir/${decompressedfileStereo}-a.sph mixer -l
$   sox $decompressedfile -c 1 $outputDir/${decompressedfileStereo}-b.sph mixer -r
$ else # File is mono
$   echo cp $decompressedfile $outputDir/
$   cp $decompressedfile $outputDir/
$ fi

Adding noise

In order to better represent the SRE12 evaluation set, 2 noisy versions (SNR=6dB and SNR=15dB) of the same segments were included to the development set (both target models and test utterances). This can be done using FaNT:

http://dnt.kr.hsnr.de/download.html

The noise samples were mainly collected from freesound.org and include HVAC and crowd noise. They are available under request. The description of the added noise for each of the audio files can be found here:

$ cd xbob/db/nist_sre12/noise_description/

Speech enhancement

The denoising of the audio signal can be done using QIO:

http://www1.icsi.berkeley.edu/Speech/papers/qio/

Using independently the file lists

The file lists of the development and evaluation sets are shipped with this package. They can be used independently, and can be found here:

$ cd xbob/db/nist_sre12/prism/

The file lists of the development set were prepared by the I4U consortium.

In case you need any help, please contact us.