Is it possible with vlc to remove the two existing subtitle tracks (leaving video and audio track unchanged) and render the srt-subtitles directly into the video (i.e. not adding a sub track)?

I would like to answer this as a two question.

1. extracting the subtitles with VLC
2. Render subtitles to video with VLC

For the first question, AFAIK, there are no way to do that with VLC. You could use MKVExtractGUI-2 to do it instead.

As for the second question, the answer is Yes, you could do so. You could do this by going into Media - Convert/Save. More about that here: http://rikardo.kinja.com/how-to-hardcode-subtitles-using-vlc-and-rendered-mp4-fi-1438028334

Is it possible with vlc to remove the two existing subtitle tracks (leaving video and audio track unchanged) and render the srt-subtitles directly into the video (i.e. not adding a sub track)?

I would like to answer this as a two question.

1. extracting the subtitles with VLC
2. Render subtitles to video with VLC

For the first question, AFAIK, there are no way to do that with VLC. You could use MKVExtractGUI-2 to do it instead.

As for the second question, the answer is Yes, you could do so. You could do this by going into Media - Convert/Save and follow the procedures.

For a detailed step by step you could follow the steps below:

Select: Media - Convert/Save

(Add) The file name of your video file

(MP4) (Check)

Use a subtitles file (Browse) to the file name of your subtitles file (SRT)

Select: Media...Convert/Save; Click on downarrow;

Select Convert ...Key in Destination file ...Select tool icon from Settings—Profile Select Subtitles tab Check "Overlay subtitles on video" Select 'Save' (this setting will be remembered for future renders)

Select 'Start' (I use the default H.264 + MP3) settings.

Source: http://rikardo.kinja.com/how-to-hardcode-subtitles-using-vlc-and-rendered-mp4-fi-1438028334