I tried whisper with a movie from the 60's and it was a disaster. Not sure if it was due to the poor quality of the sound, the fact people used to speak a bit

I tried whisper with a movie from the 60's and it was a disaster. Not sure if it was due to the poor quality of the sound, the fact people used to speak a bit differently 60 years ago or that 3 different languages were used (plot took place in France during WW2).