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Old 17th December 2020, 22:47   #7  |  Link
poisondeathray
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Join Date: Sep 2007
Posts: 5,345
Quote:
Originally Posted by nji View Post
But how to do that?

If the whole lenght is say 30min.

I prepare a timecode file manually for say 5 frames.
The fps of the cfr "pre movie" are so small (5/1800)
I probably cannot set it exact to match the audio length.

But that is necessary to combine the movie with the audio.
And after that turn to vfr by the timecode file.

5 frames total for 30 min ? That's roughly 1 frame per 6 min (not necessarily spaced evenly) . I think that is quite large - most players will probably not play it properly (a very low equivalent FPS), you might need to increase the "granularity" by adding a few duplicates . Also , most players will have difficulty seeking.

Look at the mkvtoolnix (mkvmerge) documentation on the formatting and types of timestamps under the "external timestamp files" section . ("timecodes" and "timestamps" are the same thing, the name has changed , they used to be called timecodes). v2 timestamps require an entry per frame, but they need to be "evenly spaced" in time. v4 timestamps do not, but sometimes they don't work correctly with some players

You add the video and audio, select the video track, add the timestamps file in the timestamps box. You can also add chapters to navigate by in the player and use chapter names . Those chapter points must be I-frames to be seekable

Other ways are to use mp4fpsmod for mp4 container (but does not support chapters directly) , and to add the timecodes in with tcfile-in while encoding with x264
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