saving a vob, it cuts some frames

[wanttobefree]

Hello,
I would like to add a fade-in effect in a *.vob file. Since I didn't want to recode all the vob, I cut the initial 5 seconds (from frame 0 to 132) and I added here the fading effect: so I have a vob with only the initial 5 seconds, and another one, the big one, without the initial 5 seconds. Then I put them in sequence in a DVD, so you don't notice the cut.
The problem is that, I don't know why, there is a sort of gap between the two vobs, you notice that the scene is not fluid. Indeed, when I opened in Avidemux the small one, I noticed there are inside only 127 frames instead of the 132, and that's why there is the gap. Avidemux cuts some frames at the end.
Why?
How could I solve?

Thank you

[Agent_007]

Did you cut from I frame boundary?

[wanttobefree]

The frame 132 is an I frame. I tried both cutting it (then having 0-131 in the first clip, 132-end second clip), and leaving it (0-132 first clip, 132-end second clip), it doesn't change anything when I open the first clip in Avidemux, it contains always 127 frames.
This is when I recode. Instead if I choose "copy" in "video", when I open it in Avidemux it contains 130 frames (more than 127, but however not 132 or 131)

[Jan Gruuthuse]

You're not stating what version of avidemux you use? 2.5.4, 2.5.5, 2.5.6 or 2.6? Check if you can have a later revision or upgrade up to 2.5.6. Verify your windows for 32-bit or 64-bit version and get it here: http://avidemux.razorbyte.com.au/. Make sure when encoding you use the same parameters of the original vob (video and audio codec)

[wanttobefree]

I use the 2.5.6, 32bit in a computer with Windows XP, 64bit in a laptop with Windows 7. I have the same identical problem in both computers
I have the problem even if I don't encode because if I choose "copy" in "Video" and I save it, after opening and indexing it there are only 130 frames instead of 132

[Jan Gruuthuse]

The problem is this not caused by the audio? Save audio from original video clip. And use it to replace the audio track of the edited video afterwards. Also check if the frames are on the same position as in the original. Eventually try adjusting by inserting or cutting the frame in question.
Frame type:
I-TFF (02) | B-TFF (02) | B-TFF (02) | P-TFF (02) | B-TFF (02) | B-TFF (02) | P-TFF (02) | B-TFF (02) | B-TFF (02) | P-TFF (02) | B-TFF (02) | B-TFF (02) | I-TFF (02)
the sequence of these frames could different on your clip.

[wanttobefree]

I saved the audio and edited it to the same length of the clip I want to extract, but it doesn't change: only 127 frames if I encode it.
I checked for the frames and they are different:
before saving, the video is:

0	1	2	3	4	5	6	.....	120	121	122	123	124	125	126	127	128	129	130	131	132
I(08)	B(14)	B(14)	P(11)	B(14)	B(14)	P(11)	.....	I(07)	B(11)	B(11)	P(07)	B(11)	B(11)	P(08)	B(11)	B(11)	P(08)	B(11)	B(11)	I(08)

instead after saving the clip, and opening it:

0	1	2	3	4	5	6	.....	120	121	122	123	124	125	126	127
I(04)	B(04)	B(04)	P(06)	B(10)	B(10)	P(06)	.....	I(18)	B(18)	B(18)	P(18)	B(18)	B(18)	P(18)	P(18)

The frames 127 are different and indeed if I watch the two clips I can find that they have an identical image in frame 126, instead the images in 127 are slightly different: the frame 127 of the second clip is instead identical to the frame 129 of the first one (and they are both P in fact)

[Jan Gruuthuse]

mark frame 128 with A and B and copy it:
127   128   129
move one frame back paste the copied frame:
127   128   128   129
move one frame back should still be the 127 (P18)
mark that frame (P18) with A and B and cut it:
126   128   128   129
perhaps if the sequence is back to
I()   B()   B()   P()   B()   B()   P()   B()   B()   P()   B()   B()   I()
If not looks like you have to re-encode the complete clip to have your fade-in? Unless more experienced people see what is going on and have a solution to this?

[wanttobefree]

no way every time I save the clip (even if I open and I don't do anything, just saving it with Audio and Video on Copy) it loses some frames at the end... In particular in the case written in brackets it keeps the last frame and deletes some frames before

[Jan Gruuthuse]

is this in the appended video clip happening or are you saving each clip separately?
Load part with fade in, append rest of the clip. Save clip. Do frame editing in the newly saved reloaded video? If this was the way you tried and that failed? Perhaps someone else has a better idea to achieve what you want? Or you have to do it the old way and re-encode the whole video.

[wanttobefree]

It happens with every kind of clip, and without doing anything: just opening a clip and saving it, I lose some frames at the end.
But your suggestion is a good idea, I try and I'll let to know you 

[wanttobefree]

It works your suggestion  , now the only problem is that I must leave two identical I-frames (the former from the first clip, in other words the "fading-in clip", the latter from the second, the appended), because if not I get some frame damaged... Unfortunately it is not nice because when you watch the final clip you notice it, you have the feeling that it blocks for some time (even if it is only for one frame repeated!). But at least it is better than before, since the blocking sensation was much worse (of course, since it lost frames).
Do you know if it possible to do anything to avoid this? If not, I'm happy anyway.
Thank you very much

[Jan Gruuthuse]

Can you upload small sample (original source + fade in part + part to join) and provide link to the upload. Perhaps one of the developer(s) / user(s) might pick up on this and provide solution?