KVCD: Problems with chapters sync?
 

hello everybody,
I made my first KVCD from a DVD! :D
results are very good, thought it was simple material (a live concert by Emerson Lake & Palmer), long 42 min.
but I have a little annoying problem: I tried to make the chapters as on DVD, I extracted them w/ chapterxtractor, pasted on VCDeasy, configured the correct "interactivity" etc. etc..
now when I play it either on DVD player or PC, I notice that there's a little mismatch between real chapters (in my case the songs of this concert) and ones created by VCDeasy, let's say a 500 ms delay for all the chapters, but I'm not sure...
have you got any idea why it happens?
I used smartripper for ripping, dvd2avi & headac3ache for audio (320 kbps stereo), tok for encoding and muxing (great program!) and VCD easy for authoring and burning...

thanks in advance!

bye, MAX il bYOndo

Did you "add Sequence Headers" when encoding/muxing using BBmpeg??
Cause this is useful when generating chapters afterwards.
So choose these Sequence Headers in your GOP settings (but I assume you didn't change them there) and also choose them in your muxing appl. (where btw. BBmpeg is the best IMHO)

Cheers
Inc.

nope :(
I tried any combination of parameters suggested by incredible, but w/o any changes
I have a doubt: does VCDeasy make any sort of "quantization" on the time values of chapters?
I say that beacuse I noticed that when I insert them and try to modify the "offset" in the vcdeasy window; for values under 0.8 sec it doesn't modify anything....
very very strange...
anybody that has already made this KVCD? it's "ELP: picture at an exhibition, live 1970"
please! any1 that has some ideas let me know!

thanks in advance,
bye, MAX il bYOndo

hi incredible,

by comparing the results, muxing m1v + mp2 files, with bbMPEG and TMPGEnc i found out that sometimes the TMPGEnc gives a little smaller mpg (KVCD) file than bbMPEG !!!

thanks
what IMHO stands for ???

@ Clickit

Yes and thats why BBmpeg generates more functional muxed mpegs!
Because you can add these mentioned sequence headers or SVCD scan offset headers (TmpgEnc also reports that he's doing this but ..., well ;-) )... thats why BBmpeg final streams take a few more MBs!
Some poeople say you don't need these headers as its also told in the pop up hints of FitCD in its calculating part, but IMHO ("In My Humble Opinion" ;-) ) IF you do author a VCD/SVCD containing chapters with these headers you'll be more secure that everything according to chapters will work fine.

;-)

Many times when muxing using TmpgEnc and afterwards generating the Images in VCDeasy ... the log often reports "no mpeg stream header found"!! Thats critical as by this you could get problems when entering the determined chapters with your standalone afterwards. BTW the error log "No mpeg audio header found" isn't that critical, you can just ignore it in VCD easy

@incredible

you were very enlightening :P !!!

thanks

@byondo
You are making KVCD which has GOP 24, therefore one I frame every 24 frames. The chapter entry points are positioned from every authoring program exactly at I frame. But the DVD stream has an I frame every 15 frames (PAL) or every 18 frames (NTSC). Here the chapter entries doesn't match, therefore the VCDEasy will put the entry at the nearest I frame - unfortunately it is delayed from the original DVD stream. If you want to have the chapters exactly at the same time point, you should encode with the same GOP structure as the original DVD,

thanks Abond,
it sounds like being the right way :)
in ToK I leave the option "autoGOP", so the problem is there, I think
but how can I correct it? in other words where can I find the DVD GOP and what do I have to do in ToK configuration?

thanks once more,

MAX il bYOndo

As I wrote standart compliance for PAL DVDs are 15 frames in GOP, and for NTSC DVDs are 18 frames in GOP. Unfortunately I don't think there is a way to know the setting for detection of the frame change. Well, I think if you encode selecting in ToK the GOP size corresponding to DVD type, you should be pretty close.
Another way might be if you encode every song separately. Then for sure at the beggining you have I frame. You can even load the separate encoded songs as separate .mpg files in VCDEasy and in the Interactivity tab to adjust the gap between the files at 0 sec. So you will be able to move with Next to the next song and if you want to look at the whole thing at once there would be no gaps.

As said you'll never know exact which GOP sequences are used on your orig. DVD.
Even when standard PAL says 15 max within a GOP it could be that the dvd is encoded used smaller/tighter GOPs! Also the Scene change detection will bet arbitarty, so there's only ONE way to encode with the exact same I frame GOP structure!:

Open the IFO file of the main movie VOB streams using IFOedit where the movie is stored. Use the function "Create Tmpg Template" down below. This will generate a txt. file which contains the exact GOP structure of the original.
Then when encoding in TmpgEnc. choose under GOP settings in the point "Forced picture type setting" there you can load that generated txt file and it gives to the re-encoding the exact same GOP structure! By doing this, your Chapters will match afterwards.

Thats also the way if reencoding the main m2v and afterwards remuxing it to your VOB files again using IFOedit, if Transforming gives a too bad quality.

Inc.