some odd outcome in a publish regarding file size. Any thoughts?

I have some story files that had an unpredictable outcome after publishing. One file became smaller, while the others became larger. All were output the same (or so I think), and saved as .zip files which is what moodle ultimately uploads. My question is, being that they are zip files shouldn't they ALL be smaller than the file that created them, like the one file resulted as?

 

example file 1.story = 75,751 KB in size

after publish

example file 1.zip = 53,279 KB

 

example file 2.story = 111,676 KB in size

after publish

example file 2.zip = 170,739 KB

 normally I wouldn't care that much but I have size limitations on upload and was really hoping to not make LARGER files after publishing. Is this normal behavior? Why would one file be smaller and not the others? Thanks for any thoughts.

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Update* After reading a little through the forums I'm lead to believe that Storyline disregards the file conversions done in some 3rd party products. What makes me think that that's what is happening is example file 1.story has video files placed into it that were converted differently at a much higher resolution and I think Storyline is thus compressing that LARGE file and making it smaller. HOWEVER in example file 2.story I have inserted MUCH smaller video resolution files (to cut back on file size) and the very bad result is Storyline is disregarding the GREAT compression and resolution settings I achieved with the 3rd party tool and deciding on its own what to do, thus actually making a less effective published file. Pretty bummed out. I spent a tremendous amount of time optimizing video files for this.

 

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Update with details. In 

example file 1.story = 75,751 KB in size

after publish

example file 1.zip = 53,279 KB

The video files inserted were 720x 480

 

example file 2.story = 111,676 KB in size

after publish

example file 2.zip = 170,739 KB

The video files inserted were 480 x 272

Now, what is annoying is the placeholder the asset is in on the slide IS 480 x 272 so WHY does Storyline want to make it bigger, when with the 720x40 file inserted into the 480 x 272 placeholder does it make it smaller? Its like it does a good job with the larger video resolution but not when it goes to a smaller resolution :(

 

 I mean this is almost doubling the file size on publish than the source file because of publishing. When I'm working with files that are large to begin with this is ugly. I would be ALMOST be better off to use a higher resolution video file and have storyline have a smaller published file???? Granted because I shrunk them it saved a lot... but its the principle of the matter... I mean its like two steps forward, one step back. It makes no sense. I just inserted around 600 video clips on 22 assignments and am pretty freaked out because I THOUGHT I was optimizing my video better by making them 480x272