How can I reduce my video file size?

use the ffmpeg software to reduce any video format in my case it reduces from 700MB to 100MB almost 7 times lower than the original.

use the command below todo so..

ffmpeg -i videofile.mp4 -vcodec libx264 -crf 28 output.mp4

Trim video files using FFmpeg

A much better solution is to perform “lossless” trimming. Fortunately, there is a way to do this with the wonderful command-line utility FFmpeg

ffmpeg -i input.mp4 -ss 01:19:27 -to 02:18:51 -c:v copy -c:a copy output.mp4
This will cut out the section from about 1h19min (after the -ss command) to 2h18min (after the -to command).The copy parts of the command are meant to copy both the original audio and video content without recompressing. This means that the above command only takes a few seconds to run.

ffmpeg -ss 00:00:06 -i input.mp4 -c copy output.mp4
Above command will start copying from 06 seconds to the end of the video

Convert-a-set-of-images-into-a-video

ffmpeg -framerate 1 -i frame_%d.png -c:v libx264 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" -pix_fmt yuv420p slide.mp4

ffmpeg -framerate 16 -i frame_%d.png -c:v libx264 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" -pix_fmt yuv420p slide4.mp4

ffmpeg -framerate 12 -i frame_%d.png -c:v libx264 -vf "scale=1920:1080:force_original_aspect_ratio=decrease:eval=frame,pad=1920:1080:-1:-1:eval=frame"  -pix_fmt yuv420p -crf 20 slide9.mp4

Concat multiple videos into one video file

ffmpeg -f concat -i data3.txt -c copy output.mp4

data3.txt content:

file '1_1_1__1_Introduction.mp4' 
file '1_1_2__2_Who_This_Course_Is_For.mp4' 
file '1_1_3__3-_What_You_Need.mp4' 

References:

• Sample Video files
• Github
• Stack
• Chaet Sheet
• FFMPEG VIDEO MANIPULATION
• ffmpeg Introduction
• ffmpeg-libav
• convert-a-set-of-images-into-a-video