HOW TO DOWNLOAD VIDEO FILE FROM FILMOTEKA:
    URL_FROM_FINA: //*[@id="player_10988_media"]/video/@src
    #following command downloads only voice channel
    ffmpeg -i URL_FROM_FINA -vn -acodec pcm_s16le -ar 44100 -ac 1 output.wav

CREATE SAMPLES FROM BIG WAV (30 seconds samples):
    ffmpeg -i output.wav -f segment -segment_time 30 -c copy out%03d.wav

USAGE:
    python3 reco.py INPUT_WAV_FILES > OUTPUT_FILE

HAVE FUN!