Add and or remove black frames from MKV (h.264) file without re-rencoding?

[Krawhitham]

I'm trying to sync up TV DVD audio commentary with a better quality MKV (h.264) video file. The problem is the cuts where commercials would normally be (black frames in the videos) are not the same length in time between to two sources.

In the past I have chopped the AC3 file around scenes, added blank frames to match the commercials breaks (the second or two of black frames) and remerge the AC3 file without re-encoding. But I'm running into a lot of commentaries that are talking through the “commercials breaks” so I need to make the video match the audio file instead of the other way around or else I butcher the audio commentaries.

So is it possible to add and or remove black frames in a MKV (h.264) file without re-rencoding?


Another possibility at least theoretically, you should also be able to to what I need through timecode files, It would basically make the video VFR. I do not care how I get the job done as as long as I can get the job done without having to re-code and lost quality.

Can anyone help?

[Baldrick]

Making black frames that matches your sources video exactly so you don't have to reconvert wont be simple.

Or find an advanced/nle editor with smart rendering(so it only reconverts the new black frames) and that supports mkv(or maybe mp4 or just h264 video if you remux/demux it to it first using mkv2mp4 or mkvextract ) and ac3. Maybe aviutl or moviestudio or videostudio pro.