[LAU] Slow but pitch-correct video playback

[Tito Latini]

On Tue, Sep 23, 2014 at 08:21:30PM +0200, Philipp Überbacher wrote:
> Hi there,
> 
> I encountered a nice piano learning video including hands and animated
> keys, but since it is playing at original speed it is way to fast for
> me to learn that song. In case anyone is interested, it's this video
> and I think it's rather nicely done (don't hate me for the music :P):
> https://www.youtube.com/watch?v=Ej6MF5KjuOc
> 
> I found one way which sort of works (after settings LADSPA_PATH) but it
> sounds quite horrible. Is there a better way to do this?
> http://markplusplus.wordpress.com/2006/10/01/pitch-correct-play-speed-with-mplayer/
> 
> Is there a stretchplayer for video?

The audio filter `scaletempo' should be acceptable for your purpose:

  mplayer -af scaletempo -speed 0.5 video...

it's a little better:

  mplayer -af scaletempo=stride=50:overlap=.25:search=20 -speed 0.5 video...