[FFmpeg-user] convert a video to some format and than bring it back exactly the same

[Julien Dotsev]

Hi,
When i convert a video for example using this command:

*ffmpeg -i bird.avi -c:v copy -c:a copy -y bird.mkv*

and then convert it back:

*ffmpeg -i bird.mkv -c:v copy -c:a copy -y bird.avi*

I see there is a difference in the file size. The first avi is *1462KB* and
after the reconversion is *1474KB*.

My question is is there a way to take a video file from a client, convert
it to some readable by  HTML <video> tag format and after I finish using it
be able to bring to the client the original file, exactly the same. Storing
the original file is not a solution in my case.Storage problem.

Thanks in advance,
Julius