Frame-accurate VOB cutter

[zagortenej]

Hi,

I am looking for the program that will enable me to load VOB file, preview it, mark in/out the start/end VOB cut points, and export the new file in VOB format without re-encoding. I am aware of MPEG2cut and Chopper XP tools but neither has frame-accurate marking capagilities. MPEG2cut allows for mark in/out every 15 frames which, on occasion, is not accurate enough. I believe the same is true for Chopper XP.

Any info/suggestion are welcome.

Thanks!

[jorel]

DvdShrink ?

[E-Male]

cuttermaran (with tmpgenc)
if you don't mind demuxing before and remuxing after cutting
dts is not supported and ntsc (29.976fps) doesn't work correctly, both should be fixed soon

[zagortenej]

Thanks for the replies.

I tried DVDshrink but - although a very fine tool - the problem is that iti is not frame accurate, but allows for cutting points at each 15 frames (30 sec.).

Cuttermaran (with tmpgenc) is not really what I'm looking for because it requires demuxing/remuxing and dies not support DTS streams.

So, the search is still on. Is it really possible that nobody thought of making a nice, frame-accurate VOB-to-VOB cutter tool? Is MPEG2cut really the only choice available?

Any further input is highly appreciated.

[E-Male]

i think you got no idea how difficult such a task is

you cannot cut mpeg2 frame accurate, you have to reencode one gop in many cases
so the tool you want would have to have mpeg2-encoding and vob-muxing/demuxing all integrated

what's the problem about demuxing and remuxing yourself anyway?

some information on what you wanna do would be helpfull

[Malcolm]

Originally posted by zagortenej
Thanks for the replies.

I tried DVDshrink but - although a very fine tool - the problem is that iti is not frame accurate, but allows for cutting points at each 15 frames (30 sec.).

Cuttermaran (with tmpgenc) is not really what I'm looking for because it requires demuxing/remuxing and dies not support DTS streams.

So, the search is still on. Is it really possible that nobody thought of making a nice, frame-accurate VOB-to-VOB cutter tool? Is MPEG2cut really the only choice available?

Any further input is highly appreciated.
Hi zagortenej,
i really don't believe that anyone will ever (or at least any time soon) write a software that makes frame-accurate cutting in VOB files!

if you want to do frame-accurate cutting (having a VOB file) then you (/the software) ALWAYS have to do the following steps:

- demultiplex the streams from the VOB (video, audio, subpicture, ...) (either 'on-the-fly' or to the disk first). You can't cut multiplexed streams (e.g. VOB, MPG)
- cut the video at I-frame (in-cut) and I-/P-frame (out-cut)
- reencode (+replace) the first + last GOP(*) so that you have it frame-accurate
- cut the audio
- remultiplex the streams to a VOB

(*) In MPEG2 encoding, a GOP is a 'Group of pictures'. Normally a GOP is composed of 12 or 15 frames.
For in-cuts, a GOP can't be split! That's why there's no software that makes frame-accurate cutting! frame-accurate cutting is only possible by reencoding the corresponding GOP!

for (nearly) every steps above, there are separate tools available; except for the last step(**)! i talked with several authors (DVD-Rebuilder, DVD-Shrink, VobBlanker, TitleSetblanker, Imago MPEG-Muxer), because i needed this functionality. But no one wanted to write this; simply because it's VERY VERY complicated! You can search the forum for user 'Malcolm' then you can find some threads about AC3 -> MP2, reencode audio, ... (all within the last 4 weeks).

(**) There are tools that can multiplex video + audio to a VOB file. Either you can only use one audio stream (IfoEdit / ReJig) or you can use multiple audio-streams (Imago MPEG Muxer). But none of them can multiplex (multiple) subpictures together.

Greetings,
Malcolm

[zagortenej]

Thanks so much for the info, Malcolm

After a bit more search I found out that Womble Mpeg Wideo Wizard 2003 does frame-accurate VOB cutting editing, but exported file is saved as mpeg rather than VOB. I tried it and it works flawlessly. In Export preferences, there is an option for 'GOP size compliance for DVD recording' and also a toll called 'Mpeg GOP fixer' which - I assume - corrects GOP splits you have mentioned. The sowtware is extremely fast with the added bonus of being able to make several cuts on the file and get rid of all unwanted segments in one step. And the new exported mpeg file is generated without any reencoding so the original audio/video quality is fully preserved.

So, I guess, this is the best one can get at this time. To 'convert' the mpeg file I used TMPGEnc DVD Author to load the file and have it turned into a DVD-compliant VOB.

P.S.
Is it because of all GOP issues you mentioned that MPEG2cut edits VOB with 15-frames accuracy only?

[Malcolm]

You're welcome! :)

In Export preferences, there is an option for 'GOP size compliance for DVD recording' and also a toll called 'Mpeg GOP fixer' which - I assume - corrects GOP splits you have mentioned.
Might be, did you check the documentation?

And the new exported mpeg file is generated without any reencoding so the original audio/video quality is fully preserved.
I don't believe this! :) Either there is an encoder inside, or it's not frame-accurate! :)

Is it because of all GOP issues you mentioned that MPEG2cut edits VOB with 15-frames accuracy only?
Short answer: Yes!
Long answer (but still VERY simplified): There are 3 types of encoded pictures/frames in MPEG videos:
I-frames, P-frames and B-frames.
If you have a GOP, it typically contains this sequence of frames: IBBPBBPBBPBBPBB
only the I-frame can be decoded without the other frames. all other frames can only be decoded if you also have the I-frame available!!! This is so because P-frames only contains the DIFFERENCE between the previous (I-) frame and the current video picture! B-frames only contains the diference between the previous + the next and the current video picture! If you cut a GOP and loose the I-frame, then you're not able to decode the remaining P- and B-frames!!!

Greetings,
Malcolm

[E-Male]

i looked into that program and it seems to only keep the first ac3 stream, all other audio streams are gone

[r0lZ]

Actually Womble Mpeg2 VCR (probably an old version of Video Wizard) do frame accurate editing without reencoding the whole file. However it reencodes the frames inside the altered GOPs.

[E-Male]

just like cuttermaran does
it's the smartest solution

[zagortenej]

[QUOTE]Originally posted by Malcolm


In Export preferences, there is an option for 'GOP size compliance for DVD recording' and also a toll called 'Mpeg GOP fixer' which - I assume - corrects GOP splits you have mentioned.
Might be, did you check the documentation?

- I did, but it doesn't really say much other than restating the same the option itself indicates, only in slightly different a way.

And the new exported mpeg file is generated without any reencoding so the original audio/video quality is fully preserved.
I don't believe this! :) Either there is an encoder inside, or it's not frame-accurate! :)

- There is an encoder inside, but - unless you ask for reencoding - the file remains untouched. There is also a very useful analysis report which - after file exporting is finished - lets you know how much of your file had been reencoded and at what pont. So far, everything I did reads 100% stream copy, i.e. no reencoding.

- If, as r0IZ claims, "Womble Mpeg2 VCR (probably an old version of Video Wizard) do frame accurate editing without reencoding the whole file. However it reencodes the frames inside the altered GOPs", does this mean that the only GOP's being "messed" with are the ones at the cut-in and cut-out points. If this is so, I can more than live with it.

[Malcolm]

Originally posted by zagortenej
However it reencodes the frames inside the altered GOPs", does this mean that the only GOP's being "messed" with are the ones at the cut-in and cut-out points. EXACTLY!! That's what i wrote in my first answer: 'reencode (+replace) the first + last GOP(*) so that you have it frame-accurate'

Greetings,
Malcolm