Speed up video software

[NAVVARR]

Ok, nowt to do with Shmups- but i recently drowned my Samsung S7 when I took it swimming in the sea by mistake.

I'm now back using my old Nokia 808 Pureview to watch vids when I'm sitting on the bus to work.

My Samsung S7 had a great feature where you could speed up a video without distorting the sound.

Anyone know of any software I can use to do this- got a load of mp4 vids that I watch and watching them at 1.3 or 1.4 speed allows me to get through a series quicker.

Cheers for any suggestions.

I generally record stuff on my Icecrypt T2400 and then convert the file using Handbrake - this give me Mp4s which I can then watch.