[FFmpeg-user] Get the file size in advance when encoding from one another format

[Sendex Six]

I've created a simple wrapper for FFmpeg using java and use this in a
spring boot web application, and everything works fine. But the problem is
I have this requirement that I need to get the file size of any media
format in advance from encoding to another format because I need to set the
Header Content-Length.

I did already search it online. Some of those are confusing, and the others
don't make sense.

Please help me do this; How do I get the file size in advance if I encode
any media format to another format so that I can set the Header
Content-Length in the header. What is the formula for this? I'm new to
FFMpeg.


I really appreciate any help you can provide.