preview image issues

[joeplaza14]

why is this happening. there both the same and yet one will allow me to change the preview icon and the other will not. ive tried the copy and paste method, ive tried candybar and ive tried permissions. nothing seems to work. please email me at joeplaza14@yahoo.com if you know why and have an answer.

http://i799.photobucket.com/albums/yy273/joeplaza14/Screenshot2010-06-12at63647AM.png

 

[BlueRevolution]

They probably use different codecs. QuickTime (responsible for rendering the previews) can read one of them but not the other.

 

[aslocum]

.avi is just a container format and can contain many different video and sound codecs, like divx, xvid, h.264 and even ogg and some others.
so for some quicktime can render a preview and for some not