How does scaling work in ffmpeg?

Question

I am new to ffmpeg. I just want to know how I could keep the original scale of the video. The original size of the video is that its frame width is 1820 while its frame height is 720. The original data rate is 1429kbps while the original total bitrate is 1589kbps. The original frame rate is 30.00 frames/second

How can I keep the original ones. Like I mean is that what should be my version of this below:

ffmpeg -i Happy.mp4 -vf scale=800:-1 -r 20 Lucky.gif

You see I am trying to make a gif while keeping the original properties of the video so please help me.

Also, how does scaling in general work in ffmpeg?

Answer 1

Remove -vf scale=800:-1 to avoid rescaling. Remove -r 20 to avoid changing frame rate. You're transcoding from a stream in a MP4 to the GIF codec, so the bitrate will not remain the same, nor is there any sense in trying to keep it the same.

A stream is scaled by using the scale filter in a simple filterchain -vf or a complex filterchain -filter_complex or using the -s WIDTHxHEIGHT output option.