FFMPEG Bitrate Calculation / Optimization

Question

I wrote the following wrapper for FFMPEG:

function Video($input, $crop = null, $scale = null, $output = null, $extra = null)
{
    $input = @new ffmpeg_movie         


        

Answer 1

I ended up using the -sameq flag, I read somewhere that this doesn't translate to the same quality but for now this is better than forcing the original bit rate.

Anyway, I've come across this Bash script that suggests that my thinking is right, I still don't know how to calculate the output bit rate without having the output size as a constrain. If anyone knows, please share!