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Post #214769

Author
calamari
Parent topic
Idea: Personalized preservation possible with September 2006 OT DVD's
Link to post in topic
https://originaltrilogy.com/post/id/214769/action/topic#214769
Date created
29-May-2006, 10:33 PM
The Linux mpeg-2 editing tools I've found so far aren't capable of doing what we need (for example, they get confused by the episode 3 scroll). I've located the ISO13818 (documents describing the MPEG2 standard), and I'm slowly writing my own decoder, with the goal of understanding MPEG-2. This is going to take a while: MPEG-2 is extremely complicated. But, the documentation is well written and hopefully the knowledge I gain will make advanced editing possible, beyond what we could hope for with standard programs.

I envision a customized film editing program. This would solve several problems at once:
  • Eases editing: Those creating patches won't have to worry about details like numerical offsets, lengths, etc.
  • Cut, join, etc are now a lot easier, because the video/audio can be shown and matched.
  • Edit history can be recorded and "played back". This will hopefully keep us legal? What this means is that rather than store a frame or video, it just stores a list of instructions of things to do (the edit history), so applying a patch plays back the history and the film becomes edited as if the original did it themselves. So, no portion of either video needs to be saved in patches. This should keep the patches small.
  • Should make it possible to do special edits where the video isn't re-encoded, or only the modified portions of the sequence are re-encoded (subject to the restrictions of MPEG-2).
  • The editor would understand the MPEG-2/DVD format so it won't be confused.
  • Editing would be done at the GOP level, so the whole sequence (and changes) could be seen at once.

This may be somewhat unlike a normal paint program. Only certain frames might be editable and editing those frames will affect the others. And, certain effects might be possible while others may not (it all depends on how the compression is done, which I have not even begun to explore). I'll be able to tell more as I learn more. Additionally, the tool set will probably be quite limited compared to common paint/sound editing programs, but that's okay, because we don't most of that stuff anyways. Also, we can go beyond and provide specialized tools as needed.

Anyhow, the first goal is to understand the spec better, then I can see what to expect from there. At the very least, I need to make cut/join tools that work.