Converting LibreOffice ODP to Office PPT/PPTX with videos

Since I have not bought Microsoft Office, I would use Libre Office Impress to make presentations.  It is easy to export it to PowerPoint format (ppt or pptx) and send it to others who work on PowerPoint.

However, the above statement is only true as long as you do NOT have videos in your presentations.  Libre Office can deal with the videos fine as long as it is in odp format.  When export it to ppt or pptx, the videos are simply lost...

After researching for a while, there are two things you should pay attention to when making presentation with videos, and especially when you are like me, using free Libre Office.

(1) Video format - You probably should stick with WMV if your target is playing the presentation with PowerPoint, because these formats would have greater compatibility with older verions of Office/Windows.  So what you need is a video converting software when what you have is not wmv/avi.  Just google around, you should be able to find some free ones from time to time, but note that some free software might leave watermark on your video. I tried the following two, and both are ok.
Pavtube Free version from here: http://www.multipelife.com/free-video-dvd-converter-ultimate
Any Video Converter Free Edition: http://www.any-video-converter.com/download-avc-free.php

(2) If you have PowerPoint, then fine, just insert your wmv files into the slides.  But if you are also using LibreOffice, remember to check the "Link" box (shown below) when inserting a video into slide.

Also put the video files in the same folder as the ODP/PPT file.  Then save the presentation as "PPT" format.  Now you can verify if the PPT works by sending to someone with PowerPoint, or simply download the free PowerPoint viewer from Microsoft.  Note that do NOT save as "PPTX", when you do that, the videos would disappear... I still cannot figure out why.  It does not matter you check the "Link" or not, PPTX simply do not work.  I guess we might have to wait for an update form LibreOffice for that.

Buying an air purifier (update)

After using the air purifier for a few months, I'm quite sure it can actually lower the PM2.5 level.  How do I know?  Coz I've also bought a PM2.5/10 detector (You can get a cheap one for around US$40-50).  Does it help my cats and myself to relief allergic symptoms... hmm I'm not too sure.  Sometimes it seems a little better, but the result not significant enough to convince me yet.  I did not turn it on 24 hours/day though, usually only 8-12 hours/day when I'm at home.

Anyway, one thing for sure, the HEPA filter is expensive, so I bought some cheaper filters from 3M and put them in front of it in the hope that the HEPA can last longer.  And it looks good as the 3M filter got really dirty after 3 months, and the HEPA still look relatively clean.  I actually also put some sponge, which is really cheap, in the very front to reduce large particles from getting inside.

Most economic air purifier probably has simliar struture: (1) front filter to block large particles (in my opinions, the holes are usually too large, and still a lot of dust can get in),  (2) Active carbon filter, (3) HEPA filter

My setup: Front filter -> Sponge (really cheap) -> Active carbon filter -> 3M filter (more costly, but still cheaper than HEAP replacement) -> HEPA

HEPA with 3M filter:

Sponge