A/V Sync Problem: Sefy's Ultimate Newbie DVD Guide v2.0

[postul8or]

I'm using Sefy's Ultimate Newbie DVD Conversion Guide v2.0 and I use the force film as he says. When I do this, DVD2AVI captures at 24fps. TMPEG SVCD (film) template encodes to SVCD @ 23.976fps but the .wav file I believe is still at 24fps so it is falling behind the video causing Audio/Video Synchronization problems.

What do I do here?

[Sefy]

I Think if you notice carefully, I actually say I DON'T recommand Force Film!
Others will tell you to use it, but i'm not in favour of it, I suggest you retry it
and this time re-create the D2V without the Force Film feature.

[postul8or]

Yeah I tried that and the video and audio is synchronized now.

I guess I'm wondering if the source on the DVD is truly 24fps (23.976 or whatever) if it the quality of a VCD/SVCD would be higher if you used that as an input rather than an interlaced 29.97fps source.

The only other generic question I have is in the video source setting section, what is the importance of "field order". What is the difference of using "Top Field First (Field A)" instead of Field B?

[Sefy]

Regarding the Video Quality at 23.976, personaly, and I speak only for me, I
have seen no difference in quality, others claim 20% boost in quality, I think
if it was that high, i should notice it, but I don't, but that's just me, I could be
wrong, and I just can't see the difference.

Regarding the Field Order, I just let TMPGEnc select the best one for me, I've
never really played with it

[adam]

With the exception of anime and tv series, nearly all NTSC DVDs store the film at 23.976fps and telecine it to 29.97fps during playback. Using forced film preserves the progressive 23.976fps material and allows you to duplicate the same process on your SVCD, DVD, or VCD. You literally save %20 of your bitrate, which should logically translate to %20 higher quality. To my eyes the difference in quality is quite clear, but if you don't see it you can simply lower your bitrate, and your filesize, by %20 and achieve the same level of quality in a much smaller filesize. With mpeg2 encoding you should never get any sync problems, so there is really no reason not to encode at 23.976fps if that's how your DVD was encoded. Sorry to overrule you Sefy, but the very fact that %99 of all commercial NTSC DVDs (exceptions noted above) use this method should make it clear that this is a very effective means of increasing quality. To each his own, but if done correcty there is absolutely no downside to encoding in ntscfilm so even if you don't see any quality difference, at the very least is just speeds up encoding. %20 less frames to encode means %20 faster encodes.

When you encode at 23.976fps and let the DVD player do the telecine, it creates new frames in real time. The playback speed doesn't actually change, %20 new frames are just created to increase the number of frames every second. So there is literally no way that the audio can go out of sync.

I am quite sure that your problem lies in your method somehow. You said that dvd2avi was exporting 24fps footage? Well if it actually says 24fps than you are not using an official version of dvd2avi. There are several modified versions which export 24fps and everyone of them has bugs regarding sync. I recommend you use 1.76, and preview your movie in dvd2avi and let it get past the credits. If it says 95% film or higher than forced film will work so enable it. You will get 23.976fps output. If you then use the ntscfilm template in TMPGenc than I guarantee you won't run into any sync problems and you should notice a decent increase in quality. (the higher your bitrate the less you will notice it.)

Field order setting makes no difference if you used forced film because you have no fields. If however you don't use forced film, you must insure that you set your field order correctly otherwise you will get unwatchable results. I have posted numerous times how to check field order with TMPGenc, so just try a forum search. The good news is that you rarely have to do this if your source is an NTSC DVD. Forced film takes care of everything for you.

In my opinion, using forced film is the single most important step in ripping an NTSC DVD to another format. There is simply no other way to make such a substantial increase in quality, plus it eliminates most of the problems inherant with encoding interlaced footage.

[Sefy]

Adam, I'm not arguing with you about it, i'm simply saying that for me, i've
not noticed a single difference in quality, but I do know that over 60% of all
those who used NTSC Film, came to some sort of A/V sync problems.

P.S. - I did just for the fun of it, reduce the Bitrate by 20%, and sorry to say
I did see a major difference in quality, it was hurrible.

P.S.2 - I'm still waiting for you to tell me what's up with the guy who was in
the mood of helping change the guides interface, and also with the menus /
chapters that you are supposed to be working on

[adam]

I'm not trying to argue Sefy, this is a widely accepted practice and an industry standard. I'm not suggesting you should see any visual difference, that is up to your eyes. What I am suggesting is that encoding in ntscfilm as opposed to ntsc most certainly will have incredibly beneficial effects. Regarding sync issues, if done correctly there should be none. The fact is that I think there are very few people who either don't make use of forced film in dvd2avi, or don't IVTC their NTSC DVD sources. If you look at how film is actually telecined there is simply no reason not to, at least when encoding in mpeg2.

Regarding the guides, the last msg I sent you said that I had not forgotten about you, but that I would be away for a while. I am in law school and am very busy. To be honest with you the DVD you chose, despite being a great movie, has a very complex menu structure and is not easy to create menu's for. All in all I can recreate the menu's and features on a (S)VCD quite easily, but making a guide that actually explains how to do it is incredibly tough.

[Sefy]

I Think this is where the problem begins, I don't do SVCD/MPEG2 encoding,
I only do VCD's, and those who came upon this problem, also did, so maybe
that explains the A/V Sync problems, what do you think ?

Anyway, take your time, i'm patient, i've put the v3.0 Guide on hold, as you
can see, users love to complain, but not tell you what they want to improve.
In the meantime I released a couple of more "mini" guides

P.S - Here's a funny one for you, i've started working in one of Israel's Law
Colleges, i'm the Administrator/Support person there, coinsadnce with you
finishing law school ?

P.S.3 (coming soon!) - Regarding the menus, don't over due it, just show how
to make it, don't try to duplicate the entire DVD, I mean come on, just give
an example of how to do it, don't overdue it

[adam]

VCDs are slightly different. The VCD standard supports ntscfilm natively, there is no pulldown flag applied. The DVD player is supposed to telecine the VCD automatically. Some players do this poorly or not at all. As a result, a perfectly compliant ntscfilm VCD may be jerky or out of sync on one player and play perfectly on another. In practice I have never actually found a dvd player which couldn't properly play an ntscfilm VCD in perfect sync, but I have seen plenty of people complain of the problem so I'm sure it exists. As far as DVD or SVCD, or mpeg2 in general, the pulldown flag seems to do the trick every time. I seriously doubt that there is a single dvd player that cannot properly telecine an ntscfilm DVD or SVCD in real time. If such a DVD player existed it would not be able to play commercial DVDs.

Congratulations on the job, last time I spoke with you I think you were heading for an interview. Finishing law school? I wish, I'm only in my second semester.

I'm sorry this portion of the guide is taking so long. If its any consolation, my own guide on the subject took much longer

[vitualis]

Completely aside but...

NTSC-FILM VCDs sometimes don't work that well if you need to force PAL output from the DVD player (i.e., get the player to do an NTSC --> PAL conversion).

Regards.

[Sefy]

@Adam, yup, I got the job, it's only part time, but since i'm finaly starting my
migration to New-Zealand, i'm not all that worried, atleast i'll finally get out
here. And take your time, just remember, v3.0 of the guide depends on you

@Vitualis, I Think you better come visit Israel, all of our first DVD Players are
NTSC which had to do NTSC => PAL conversion because the TV's were PAL,
and they all worked great :P

[vitualis]

I'm talking in generics...

The situation is similar in Australia too. However, as I stated, although a player may be able to do 29.97 fps NTSC --> 25 fps PAL just fine, not all can convert from FILM framerates (on a VCD) to PAL well.

Regards.

[Sefy]

I Think i'm actually encountered that problem, but i'm not sure about it yet.
Not here in Israel, but when I lived in Australia 2 years ago.