[FFmpeg-user] xmedian questions

[list+ffmpeg-user at jdlh.com]

On 2020-12-31 17:25, Mark Filipak (ffmpeg) wrote:
> 1, Median? Really? (Or maybe really average?)
>
> For inputs = 239+15+15+15:
> median = (239+15)/2 = 127
> average = (239+15+15+15)/4 = 71
> For inputs = 239+239+239+15:
> median = (239+15)/2 = 127 (again)
> average = (239+239+239+15)/4 = 183

It jumped out at me that the expressions you are computing for "median" 
don't match the definition I am used to. It looks like you are computing 
the average of the largest and smallest samples. I understand "median" 
to be a value such that half the samples are greater than or equal to, 
and half are less than equal to, the value.

For inputs = 239+15+15+15:
median = 15 (239, 15 >= 15; 15, 15 <= 15)
For inputs = 239+239+239+15:
median = 239 (239, 239 >= 239; 239, 15 <= 15)

So, how to you define "median"? And how does FFmpeg?

      —Jim DeLaHunt