  Spoken content processing (such as retrieval and browsing) is maturing, but
the singing content is still almost completely left out. Songs are human voice
carrying plenty of semantic information just as speech, and may be considered
as a special type of speech with highly flexible prosody. The various problems
in song audio, for example the significantly changing phone duration over
highly flexible pitch contours, make the recognition of lyrics from song audio
much more difficult. This paper reports an initial attempt towards this goal.
We collected music-removed version of English songs directly from commercial
singing content. The best results were obtained by TDNN-LSTM with data
augmentation with 3-fold speed perturbation plus some special approaches. The
WER achieved (73.90%) was significantly lower than the baseline (96.21%), but
still relatively high.
