Merge Audio, Video, Subtitle, PPT

A friend of mine had a video.

He wanted to know how to include a background score to the video, then add subtitles, then prefix a few PowerPoint slides and suffix some more PPT sides.

I asked another friend of mine. She told me to use Camtasia software which call provides all the functionality that I needed. And that a .srt created by Camtasia stores the subtitles. The other output from Camtasia, presumably an mp4, along with the .srt file could be played together on VLC player to provide the necessary functionality that we are looking for.

Except that Camtasia is a licensed software and we could use the demo version. Usually a demo version has limited functionality and can be used for only a limited period of time. 

I searched for other ways to address this issue.

Google provided some solutions

Adding subtitles to videos:

Subtitles:

1. https://www.wikihow.com/Add-Subtitles-to-YouTube-Videos using YouTube
2. https://www.kapwing.com/subtitles - Free version leaves a watermark
3. https://www.online-tech-tips.com/computer-tips/how-to-add-subtitles-to-a-video/ - To be verified
4. https://www.videoconverterfactory.com/tips/add-subtitles-to-mp4.html - To be verified

Adding audio to videos:

Audio

1. https://support.google.com/youtube/answer/94316?hl=en using YouTube

It seems like adding audio and subtitles are fairly straightforward. You just need to go to YouTube and follow some steps. The issue I found is that while audio stays added, subtitles are not displayed in the video. Though, in  the YouTube design studio I can see that the subtitles are in place. 

Now we come to the slides. Here the procedure a friend suggested is different. One of the easiest ways is to start from the PPT and then give the link to the video from within the PowerPoint.

https://support.office.com/en-ie/article/insert-or-link-to-a-video-on-youtube-8340ec69-4cee-4fe1-ab96-4849154bc6db.

Now the PPT presentation has to be converted to a video format.

1. https://support.office.com/en-us/article/publish-your-powerpoint-slide-show-as-a-video-to-youtube-ab3e03fd-a0fd-46aa-8d4d-4ac0bf62fd5b

The issue is that I have not been able to make the exported video, from such a PPT having an embedded link to an external video, to work. 


How to convert portrait video to landscape mode:

1. https://www.instructables.com/id/How-to-Convert-Portrait-Video-to-Landscape/
2. www.kapwing.com/pricing: This tool gives an option to change aspect ratio which solves the problem. Go to design studio and click Resize. The issue is that the free version of the tool leaves a watermark. The tool is very slow though. The online user interface is confusing.

How to Merge videos

1. https://mergevideo.online/merge-mp4 - upload file from computer. When I chose the use URL option, I was not able to find the button to merge!

As things stand now, the procedure sends to be to 

1. Add audio to the video
2. Convert video to landscape mode. This step and the audio step can be interchanged.
3. Convert PowerPoint slides into a video.
4. Merge all the videos.

The addition of subtitles, either in YouTube or in Kapwing is rendered ineffective when convince with the other steps.