Is it possible to reduce the maximum I-frame interval without re-encoding?

[Ruut]

I have some 6 AVI's encoded by XviD v 1.2 wich have some commercials inside.
When I try to cut these out the cuttings are not accurate because one can only cut at the Key-frames. Since these may be as far apart as 240 frames, the cut cannot be made more accurate than about 10 seconds, which in my case is not accurate enough.
To accomodate I could re-encode the complete AVI - using VirtualDub - wth a maximum I-frame interval of say 25, which makes possible a cut of 1 second. That would be very suitable.
However I was thinking that maybe with the right tool a complete re-encode wouldn't be necessary?
Anyone aware if such a tool exists?

[guns1inger]

Nope. What you are basically talking about is re-encoding. The I-frame is the foundation frame for temporal compression. To change the I-frame interval completely changes the compression and is re-encoding. What you really want, and what doesn't seem to exist in the mpeg4 world, is something that will let you make your edit, and only re-encode the GOP you make you cuts in. This is how mpeg-2 editors work, but I have never seen anything similar for Xvid/Divx etc.

[celtic_druid]

VirtualDub 1.7 has a smart render feature which should do what you want. AVIDemux has a smart copy mode which does something similar.

[Ruut]

Thank you both very much for responding!
I have tried the Smart Render option of Vdub 1.7. Whichever compression method I choose: as long as Smart Render is selected the I-frame interval remains unchanged in the resulting AVI.
I have also tried to install AVIdemux, but got stranded halfway: it requires sweveral additional packages, the installation of which wasn't very clear to me: it seemed to be geared towards programmers, which I am not.

So, alas, as Guns1inger pointed out, the only way forward to me is re-encoding!

[jagabo]

The smart rendering feature in VirtualDub 1.7 allows frame accurate cutting. It only re-encodes the small portions around the cuts, ie within the GOPs that were cut. It would have no effect on the rest of the video which would be direct stream copied.

[Ruut]

Ahhhh, now I understand! Thank you very much, Jagabo!
I tried it and it works perfectly: amazing!
That's probably what celtic_druid meant as well.
Anyway thanks to you all: Problem solved!