video resolutions, ffmpeg notes

# Version 1: Full WxH specification
ffmpeg -i input.mp4 -vf scale=640:360 output_640x360.mp4

# Version 2: Width only, adjust height automatically
ffmpeg -i input.mp4 -vf scale=640:-1 output_640xauto.mp4

# Version 3: Height only, adjust width automatically
ffmpeg -i input.mp4 -vf scale=-1:360 output_auto_x360.mp4

Explanation:

ffmpeg -i input.mp4: This specifies the input video file. Replace input.mp4 with the actual path to your video.
-vf scale=...: This applies the scale video filter, which resizes the video.
640:360: This sets the output resolution to 640 pixels wide and 360 pixels high.
640:-1: This sets the output width to 640 pixels and tells FFmpeg to automatically calculate the height to maintain the original aspect ratio.
-1:360: This sets the output height to 360 pixels and tells FFmpeg to automatically calculate the width to maintain the original aspect ratio.
output_*.mp4: This specifies the output filename. You can change this to whatever you want.

Important Notes:

FFmpeg needs to be installed on your system for these commands to work.
These commands assume your input video has a valid aspect ratio that FFmpeg can use to correctly calculate the missing dimension when using -1.
If you need to change the output container from .mp4, simply change the file extension.

joe-oli/descale-downgrade-video-res.md