user12430: I have two videos, from one I create a mask.
In preview I have output fine.
Preview:

In RAM preview and render queue, output is weird:

I am a beginner ,using After Effects CS6 trial.
I have followed several masks tutorials, not a single tutorial has addressed this issue. I am using no effects at all, there are only 2 videos.

user14292: Set the RAM preview resolution to full.

12430: <p>I have two videos, from one I create a mask.</p>

<p>In preview I have output fine.</p>

<p>Preview:
<a href="https://i.stack.imgur.com/Ck9AA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ck9AA.png" alt="enter image description here"></a></p>

<p>In RAM preview and render queue, output is weird:
<a href="https://i.stack.imgur.com/a2J2q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/a2J2q.png" alt="enter image description here"></a></p>

<p>I am a beginner ,using After Effects CS6 trial.</p>

<p>I have followed several masks tutorials, not a single tutorial has addressed this issue. I am using no effects at all, there are only 2 videos.</p>
 14292: <p>Set the RAM preview resolution to full.</p>
