Dynamic Temporal Alignment of Speech to Lips

Many speech segments in movies are re-recorded in a studio during post-production, to compensate for poor sound quality as recorded on location. We present an audio-to-video method for automating speech to lips alignment, stretching and compressing the audio signal to match the lip movements. This alignment is based on deep audio-visual features, mapping the lips video and the speech signal to a shared representation. Using this representation we compute the lip-sync error between every short speech period and every video frame, followed by the determination of the optimal corresponding frame for each short sound period over the entire video clip. We demonstrate successful alignment both quantitatively, using a human perception-inspired metric, as well as qualitatively. The strongest advantage of our audio-to-video approach is in cases where the original voice in unclear. In these cases state-of-the-art audio only methods will fail.