For my
timestretching needs for a long time I just used BSPlayer with chronotron. 2xAV wasn't good enough, nor were any of the many other speed/tempo/pitch adjuster WinAMP plugins.
Switched to a combination of BSPlayer , Adapt-x and StudioTime (from acondigital) , resulting in better time scaling quality with lower CPU usage.
Then ended up with The KMplayer (not to be confused with KMplayer for KDE) resulting in an even lower CPU usage, VLC-like portability, but lower audio quality, though still plenty good enough for watching stuff @ 3x speed, the max speed it plays most files.
Rarely also use GOMPlayer that goes up to 4x speed but isn't as portable.
For analog media, trusty old JVC S-VHS VCR /w Dynamic Drum.