Adding Subtitle

[Motim]

Hello Forum,
Recently I tried to add subtitle to a video mp4 file. The video file was with chapter marks and I could select to any chapter. After adding the subtitle - which was OK, the chapter marks gone. Right click on the playing video did not show chapters menu, and file became almost twice in size.
Original file was 576 MB and the final file is now 1.02 GB.
How do I keep the chapter marks when starting the process ? and how to get the final file size almost same as original file ?
Original file is mp4, 1280 x 720, 25 fps, 1250 kb/s
Output file is mp4, 1280 x 720, 25 fps, 2528 kb/s
VLC player 3.0.6 version
System is win 10 pro 64bit
Answers will be appreciated.
Thanks
Motim

[unidan]

Hi,

I'm not sure this is 100% supported, try using a muxer application instead (ffmpeg for example).