Quantcast Simple Approach to Re-Encoding? (Not Transcoding) - Page 2 - digitalFAQ.com Forums [Archives]
  #21  
07-16-2004, 12:01 PM
Boulder Boulder is offline
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I've not written much about reauthoring, just the basic usage of Restore24(). I still don't understand how they could create such crap from a film NTSC source->PAL transfer..
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  #22  
07-16-2004, 01:14 PM
SansGrip SansGrip is offline
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I was thinking about how one could split the re-encoded elementary stream into its constituent cells without confusing the MPEG decoder, and came up with a simple solution. It's simple to describe, but probably very difficult to implement .

Imagine we have two cells, A and B, which we joined in order to re-encode. The end of cell A looks like:

...-B-I-B-P-B

and the beginning of cell B looks like:

I-B-P-B-...

Joined, that would become:

...-B-I-B-P-B- <joined here> I-B-P-B-...

But let's say after re-encoding, the same frames look like:

...-P-B-I-B-P- <split here> B-I-B-P-...

We can't split there because the new cell B must start with an I frame, and also because the end of the new cell A could potentially be corrupted due to the missing end of the GOP (in this instance it wouldn't, because it's missing only a B frame, but a missing I or P frame could cause problems).

The solution is to convert, before splitting, the last GOP of cell A and the first GOP of cell B to I frames. In our example:

...-B-I-I-I-I- <split here> I-I-I-I-...

With this achieved the split could be made at precisely the right point without losing or corrupting any frames, since I frames are self-contained and do not reference other frames or GOPs.

This would probably require the join code to implement a mini MPEG decoder and encoder, but should be possible.

Thoughts?
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  #23  
07-16-2004, 01:21 PM
Dialhot Dialhot is offline
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Why don't you just decide to split "to the next I frames found after the original cut point" ? Okay that can change a little the cutting point...

But that can be "the nearest" I-frame, and the error will by of 9 frames max (18 frame max in a NTSC GOP).
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  #24  
07-16-2004, 01:36 PM
SansGrip SansGrip is offline
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Quote:
Originally Posted by Dialhot
Why don't you just decide to split "to the next I frames found after the original cut point" ? Okay that can change a little the cutting point...

But that can be "the nearest" I-frame, and the error will by of 9 frames max (18 frame max in a NTSC GOP).
It can change the cutting point, and that's the problem. My goal is to keep the exact same structure as the original VOB.

Here's a paper describing one technique for splicing motion-compensated data in the middle of a GOP.
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  #25  
07-16-2004, 02:48 PM
vmesquita vmesquita is offline
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Hi SansGrip,

Nice to see you around with such an amazing tool idea.
There's a MPEG splitter that can split in any frame, converting B/P frames in I frames by reencoding. I read about it in doom9 a while ago, but unfortunatelly I can't remember the name. I'll do a search and get back to you later, maybe it's opensource so you can check how it works. Sorry for the bad memory.
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  #26  
07-16-2004, 03:25 PM
kwag kwag is offline
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Quote:
Originally Posted by SansGrip

Thoughts?
Hi SansGrip,

Split at header points. Not at I frames.
That way, every splitted chunk is a valid mpeg file.
That's the way I split files with "DIKumciser".
I also add a valid ending signature.
You don't need that last signature if you plan on joining them again, but you do need it if you want to import the pieces into an authoring program.

-kwag
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  #27  
07-16-2004, 04:14 PM
SansGrip SansGrip is offline
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Quote:
Originally Posted by kwag
Split at header points. Not at I frames.
What are header points? The GOP header?

Quote:
That way, every splitted chunk is a valid mpeg file.
Valid, yes. Split at precisely the same point as the original program (or PGC, or title, or whatever), no.
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  #28  
07-16-2004, 05:22 PM
bazzy2004 bazzy2004 is offline
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gr8 idea, but got a few questions...

wil you be able to put more then one dvd, on a dvd-r, keeping the menus etc.. ?

bcuz, i bought a 4 in 1 dvd from pakistan, you could tell it was not legit, but it was quite good..

it had a first menu, which takes u to all four movies, then wen u choose one, it actually shows the proper menus, like on the retail dvds. with all extras, etc. the quality was ofcourse near dvd, with ac3 sound, but u could tell it had been trascoded.

it was a DVD-9, with 4 movies, so we should get 2 movies, with original menus, extras, etc on it with no problem..

but the question is how...?

i leave it to you sansgrip.

Bazzy
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  #29  
07-16-2004, 05:30 PM
Dialhot Dialhot is offline
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Quote:
Originally Posted by bazzy2004
wil you be able to put more then one dvd, on a dvd-r, keeping the menus etc.. ?
That is technically possible by creating a VMG menu above all imported menus, tht have to be VTS menu then. It seems that is what your pakistanish DVD use.
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  #30  
07-16-2004, 05:39 PM
bazzy2004 bazzy2004 is offline
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yes, but how do i do that ?

thats the question - not is it possible

dvd lab
dvd lab pro
tmpgenc
meastro
spruce
scenerist ($30000 )

??

Bazzy
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  #31  
07-16-2004, 05:46 PM
Dialhot Dialhot is offline
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Quote:
Originally Posted by bazzy2004
thats the question - not is it possible
You are posting your question in a thread that is on a "under study" software ! Your question use the future ! And I am supposed to understand that you ask how to do that NOW ??? :banghead:

"Yes it WILL (perhaps) be possible" was the answer to the question you had posted before. "NO it is not possible" is the one to the question you ask now.
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  #32  
07-16-2004, 05:52 PM
bazzy2004 bazzy2004 is offline
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thank you very much, for you kindest of replies.

but i was only asking.

Bazzy
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  #33  
07-16-2004, 06:03 PM
Dialhot Dialhot is offline
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Quote:
Originally Posted by bazzy2004
GVBFbut i was only asking
There is no problem in the question (or even questions). The issue was only in the sarcastics smilies you used after my answer while the fault was in the asking itself.
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  #34  
07-16-2004, 06:05 PM
bazzy2004 bazzy2004 is offline
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ok sorry
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  #35  
07-16-2004, 06:12 PM
SansGrip SansGrip is offline
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Quote:
Originally Posted by vmesquita
Nice to see you around with such an amazing tool idea.
It might turn out nice if I can ever get my head around MPEG2 program streams, MPEG2 video, VOBs, and IFOs .

Quote:
There's a MPEG splitter that can split in any frame, converting B/P frames in I frames by reencoding. I read about it in doom9 a while ago, but unfortunatelly I can't remember the name. I'll do a search and get back to you later, maybe it's opensource so you can check how it works.
That would be awesome if you could. Splitting the re-encoded elementary stream looks to be the most difficult part. Demuxing looks (relatively) simple. Remuxing is more complicated, but I don't think as complicated as the splitting.

I have a whole bunch of ideas in my head and I want to try to nail them down, so I'm going to use this post to try to sort out some thoughts. You don't have to read it, it's more for my benefit than anyone else's .

I've been trying to back up The Shield (season 1, volume 1). It's one dual-layer DVD with some VMG nonsense (copyright, studio animation, etc.) and four titlesets. The four episodes are in VTS 3, each in its own PGC. There are about 22 cells per PGC, divided into 10 or 11 PTTs. The root menu is also in VTS 3.

The first steps were easy: copy to HD with DVD Decrypter and remove unwanted junk with DVDReMake. I then used IfoEdit to pull out the cells for episode 1 into their own VOB (actually, two VOB files, the second only small), and DVD2AVI to demux the audio and prepare the d2v file. I wrote an Avisynth script to IVTC and smooth, and used CCE to re-encode the 45-minute episode.

Now the fun begins. I cannot remux the video into the existing VOBs because neither VobEdit nor IfoEdit can remux CCE-encoded video (the end result jumps and jerks because of some timing bug). I cannot simply replace the VTS VOBs with new ones because the re-encoded video is in one big chunk, not split into cells, and this would cause the scene selection menu to stop working.

What I need to be able to do is mux the m2v with the audio (again, easier said than done, except by authoring a new DVD in IfoEdit and then deleting the IFO and BUP files it creates) and then somehow split that up into sections corresponding to the cells on the original. I then need to be to join those VOBs to form a whole one again, and replace the original VTS 3 VOBs with the new ones. In theory they should be identical except for the stripped streams and the file size, so I could then rewrite the IFO file(s) to reflect the new data. Once this is achieved all the menus should still work, including the scene selection screens, and I can happily burn away...

I've tried every single tool I can find to do this, but none of them seem to be able to do it. Either there's a bug (IfoEdit video remuxing, for example) or the tools can't handle the muxed VOB (because it's two files, and they only work with one). Right now I can't see any way of doing it while maintaining the functionality of the scene selection menus.

What I'd like my tool to do, then, is list the contents of the DVD and allow me to "check out" certain elements (cells, programs, PGCs, etc.). It will demux these elements from the VOBs and present them in the destination directory.

I can then manipulate these elements in whichever way I see fit, and "check them in" to the DVD again. The tool would take care of fixing up the VOBs and IFOs to accomodate the new material.

I really don't think that's too outrageous an idea. It seems a pretty obvious way of doing it, to me.

I guess I need to start with code to enumerate the contents of the VOBs, identifying every element within them, from buttons to video clips. This code will also need to parse the IFO files in order to present the information in an appropriate way. (I might do what DVDReMake does and have both a "simple" and "advanced" view of the structure.)

I'm done rambling now. Feel free to comment, if you managed to make it down this far .
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  #36  
07-16-2004, 06:15 PM
SansGrip SansGrip is offline
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Quote:
Originally Posted by bazzy2004
yes, but how do i do that ?
Whether or not this proposed tool will be able to do it, I don't know. I don't want to make it an authoring package -- there are already plenty of those. I'd prefer to concentrate on manipulating existing VOBs.

As for your question, you should be able to create a VMG menu in any authoring package. Scenarist will do it for sure, and I'd be very surprised if DVDMaestro doesn't.
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  #37  
07-16-2004, 06:18 PM
bazzy2004 bazzy2004 is offline
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puzzled me, but as i was reading, it made very good sense...

but like they say, in one ear, out the other.. similar effect


but seriously - this seems like a very gr8 idea!

revolutionize the kdvd scene...

Bazzy
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  #38  
07-16-2004, 06:21 PM
bazzy2004 bazzy2004 is offline
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Quote:
Originally Posted by SansGrip
Quote:
Originally Posted by bazzy2004
yes, but how do i do that ?
Whether or not this proposed tool will be able to do it, I don't know. I don't want to make it an authoring package -- there are already plenty of those. I'd prefer to concentrate on manipulating existing VOBs.

As for your question, you should be able to create a VMG menu in any authoring package. Scenarist will do it for sure, and I'd be very surprised if DVDMaestro doesn't.
but the thing is, i want to re-encode, not transcode u see... thats why im so interested in your tool you are creating
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  #39  
07-16-2004, 06:37 PM
Dialhot Dialhot is offline
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Quote:
Originally Posted by SansGrip
As for your question, you should be able to create a VMG menu in any authoring package. Scenarist will do it for sure, and I'd be very surprised if DVDMaestro doesn't.
The matter is not to do a VMG but to do that above imported menus. All authoring tools I used imports vobs but not complete dvd structures. Except for tmpgenc author but it does not handle multi audio trak

Now, for sure I used Scenarist only once and that is too few to tell I know it well
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  #40  
07-16-2004, 06:48 PM
bazzy2004 bazzy2004 is offline
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u payed for scenarist???

or did u pay for scenarist

joke

Bazzy
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