lame --resample only supported for encoding

[gb96]

If nn_params['sampling_frequency'] is changed in config/nn_config.py (e.g. from 44100 to 8000) GRUV attempts to use lame to decode mp3 to wav with the specified sample frequency via the lame --resample option.

Unfortunately (as of lame version 3.99.5 published 2011) the --resample option is completely ignored in combination with the --decode option so no resampling is applied.

Consequently you might end up with a 44.1kHz wav file being used to train a model, when elsewhere an 8kHz sampling rate is assumed. This really messes up training and sequence generation. Fortunately this is easily fixed in line 30 of data_utils/parse_files.py:

Old version: cmd = 'lame -a -m m {0} {1}'.format(quote(filename), quote(filename_tmp))

New version: cmd = 'lame -a -m m {0} {1} --resample {2}'.format(quote(filename), quote(filename_tmp), sample_freq_str)