Having drker frames in animation

hey all I have problem with rendering animation. some of frames are drker than the others I tried everything but no solution. can someone halp me to remove these darker frames.


here is video and you can see some blinking… please help

Which frames ?

How are you expecting anyone to give you a specific answer if we know NOTHING about your scene, materials, lighting, render settings etc etc

Do we have to guess all these things ???

I’m sorry but I’m first time here.
this is rendered with GPU with sheep it renderfarm. i used one HDR image for reflections, one texture for ground plane. Materials of the object are shaders no textures. for light i used one point, one area light and one plane with emmision material. AO is off, resolution is 1280 * 720. output file is PNG image. 8bit with 90% compresion, clamp indirection is 3.5. 1500 samples. filter gloss is 0.5. light pass is deafult. I think thats it.