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ffmpegHow to compress video to a specific size


In order to compress video to a specific size, first calculate target bitrate as bitrate = target size / duration. Then use this bitrate in the specified command. For example, we want to get a video of 1Mb in size and our original video is 1 minute and 22 seconds in length. Then we should use 1024/82 = 12k bitrate for conversion:

ffmpeg -y -i in.mp4 -c:v libx264 -b:v 12k -pass 1 -f mp4 /dev/null
ffmpeg -i in.mp4 -c:v libx264 -b:v 12k -pass 2 out.mp4ctrl + c
-i in.mp4

input video file

-c:v libx264

use H.264 codec

-b:v

set video bitrate

12k

use calculated value, not that final video weight more than 1Mb because of additional audio channel data

-pass 1

first pass to analyze video

-pass 2

second pass to encode video using collected data