Why mkv remux does change video stream bitrate?

[riverplate86]

I have remuxed a few mkv files so I coud add subtitles to my mkv films.
I know remux does not change any parameters of the stremas (audio and video) because there´s no recoding, only remuxing.
But if I look at me media info of the actal and the previous mkv file, I can see al slighty different bitrate on the stream video (a few kb/s diffrerent).
How can it be if the remux process does not touch the video neither the audi stream? (the audio stream remains exactly the same).
Thank you in advance.

[deank]

Subtitles are muxed in-stream, so it is normal to have slight change in output bitrate, reflecting the newly added subtitle tracks.

Other than that, mediainfo may not report the actual (nominal/real) bitrate quite correct + it depends on the version of mkvmerge you used. Bitrate differences of 1-10kbps should not make you worry - it is obvious that with simple remux video is not changed.

[riverplate86]

Subtitles are muxed in-stream, so it is normal to have slight change in output bitrate, reflecting the newly added subtitle tracks.

Other than that, mediainfo may not report the actual (nominal/real) bitrate quite correct + it depends on the version of mkvmerge you used. Bitrate differences of 1-10kbps should not make you worry - it is obvious that with simple remux video is not changed.

Thank you very much, I tryed also using SUPER and the result is the same: the audio stream bitrate remains exactly the same but the video stream bitrate slighty changes.

I appreciate your help.

[Keiyakusha]

As I remember from mkvtoolnix thread, bitstream changing is a normal thing. Thats how it works. But bitstream, muxed to mkv should give the same result as not muxed one, when decoding is done.