How to post videos from camera to instagram

I took a video with my camera but I also wanted to share it on instagram. If you wanna post videos onto instagram, you gotta save the video in your iphone's camera roll right? So that means we gotta do 2 things:
1) Convert/Trim video
2) Transfer/save onto iphone's camera rol
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Before I start my noob-ish tutorial (I'm sure there are some other ways to do this rather than my way, but idk, maybe this is what you're looking for), I have to say that there are several other softwares/programs other than those that I've mentioned that can do the same thing. I'm sure you know what you have so just play around and see if you can do the same thing. All the programs/apps I used are all free to download, or were already installed on my laptop.
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1) Converting/trimming the video 
I trimmed the video with Windows Live Movie Maker (what! don't judge). It's pretty straighfoward: just click "view" and then "trim". You don't have to trim it to exactly 15seconds, just short enough for the file size to be not too big, but still have the part you want to post (ok, obviously..). WLMM only saves in .WMV format, so i just saved the file, opened it in Quicktime and saved it again as .MOV. (ok i'm actually not sure if i have to convert it to .mov, but i just did it because its fast to save and better than wasting the time to find out if i have to convert.)

Note: Video need not be in 1:1/square format. I saved the file in 640x480.

2) Transfer/save onto iphone's camera roll
I saved the video onto my dropbox on my laptop, which allows me to access the file on my iphone. Another alternative way is to email yourself, but I didn't try that. The syncing time is pretty fast since the file size was pretty small (18mb). When you open the file on the dropbox app on your iphone, you'll realise that the "save to" icon is greyed and you can't click it. What I did was to "favourite" the file. The app will then take some time to download the video for "offline viewing". You can view the progress on the "Favourites" tab. Once its done downloading, you'll find that you can now click the previously greyed out icon! If you click that, there will be an option "Save to Camera Roll". Save it, and then you can now access instagram and post the video from your camera roll!

Note: The app didn't crop my video to a square format, but it had the black bars. It didn't matter to me.

Yeah, there you have it. My tutorial. I've already said it's gonna be noob-ish. I just figured this out on my own and played around and this is how I managed to post a video from my camera to instagram! Hope this helps someone... If you have any questions -- don't ask, because I won't be able to answer you. HAHA. I really don't think I can! I didn't go figure out about the video format, audio, file size, resolution etc... I just clicked around and found that this worked for me. Maybe I took some extra steps but I can't really be bothered to find out other proper ways to do it because this was pretty fast & simple for me to do with apps/programs I already had. There's probably some shortcut or better way to do that, but I'll leave you to google it for yourself.

k bye.