no video only sound

Hello,
I'm downloaded the latest trail version of mixvibes Cross to see if it could be an alternative for virtual DJ. I use the Vestax spin2 as MIDI controller. I mainly want to use it to play and mix videoclips
During testing, i noticed that sometimes only the music of the videoclips played and the video stays black. When i restart Cross, sometimes it plays the same videoclip without a problem (sound and video). In virtual DJ 8 the clips are played without a problem.
What could be the cause of this problem (because i have to be sure it works without a problem on my gigs before i purchase the software)?
My laptop specs are:
hp probook 4740s/4 gb memory with win7 32 bits
controller:
Vestax spin2
Greetings, Andy
I'm downloaded the latest trail version of mixvibes Cross to see if it could be an alternative for virtual DJ. I use the Vestax spin2 as MIDI controller. I mainly want to use it to play and mix videoclips
During testing, i noticed that sometimes only the music of the videoclips played and the video stays black. When i restart Cross, sometimes it plays the same videoclip without a problem (sound and video). In virtual DJ 8 the clips are played without a problem.
What could be the cause of this problem (because i have to be sure it works without a problem on my gigs before i purchase the software)?
My laptop specs are:
hp probook 4740s/4 gb memory with win7 32 bits
controller:
Vestax spin2
Greetings, Andy