Video choppy in the beginning

[markrb]

I have used Megui to create the d2v and the avs file.
After doing the entire encode I checked it as I always do and found the beginning to be choppy. After the initial camera swing it seems to catch up and is fine for the rest of the video. Even random jumping of scenes doesn't cause this to happen.

I redid all the initial steps without encoding and played the avs in media player classic. Same thing.

Here is the strange part. If I play the Vob it is fine.
If I play another avs I made from a different episode of the same series it is fine.

It looks like dropped frames, but is this in the d2v creation, original video or avs?

I am using the latest Megui autoupdated versions of all the software. As of 6-3.

I can probably live with it, but it bugs my sense of perfection. In other words I can be anal.

Thanks,
Mark

[berrinam]

I suspect it may have to do with the interlacing or other standards conversion done on your video.
Did you use Auto Deinterlace in creating the avs script?
What did it report?
Can you post your Avisynth script?
What's the framerate of the VOB?
What's the framerate of the Avisynth script?

[markrb]

The detection said to do nothing, but there is clearly some sort of interlacing going on.

However it doesn't matter what options I put in the avs script.
I have tried it with no de-interlacing and with a few different ones all with the same result.

The video is NTSC. I haven't looked into the true framerate, but I suspect it's 24.

The avs has no framerate mentioned.

This is just one of the avs scripts I have tried. The first 2 lines are constant while the 3rd changes based on the test. Sometimes no de-interlace sometimes another in it's place.

DGDecode_mpeg2source("D:\f6\VTS_08_1.d2v",cpu=4,info=3)
ColorMatrix(hints=true)
tdeint(mode=0,full=false,cthresh=12,type=2,map=0)

If it helps this is the 6th episode of the Farscape series season 1 NTSC.

Thanks,
Mark

[berrinam]

Can you cut some of the unprocessed VOB out and upload it please (say, to rapidshare.de ?) Thanks. What I would like is
Some of the choppy section
Some of the fine section

Thanks

[markrb]

After cutting the video I looked at the cut section and it did not have the choppy playback. I am looking into why this is now.
One theory I have is that my HD might be fragmented and that this may cause initial problems until the cache catches up.
I am defraging the drive now and will start the testing over when it's done.
Other then that the only thing I can think of is that somehow Shrink (what I used to cut) did something to the stream, although it didn't fix the whole video that I tried after noticing the change.

I will post the results and if this doesn't fix I will upload whatever you need.

I am lost as to why out of the first 6 episodes I have done this is the only one with this problem.

BTW when doing just the cut section Megui says I need to de-interlace, but when it checks the whole video it says I don't have to.

Mark

[berrinam]

Other then that the only thing I can think of is that somehow Shrink (what I used to cut) did something to the stream, although it didn't fix the whole video that I tried after noticing the change.I have no idea what Shrink does, but people tend to use Chopper XP for this kind of thing, so maybe you could try that.

BTW when doing just the cut section Megui says I need to de-interlace, but when it checks the whole video it says I don't have to.This is what I suspected. What it means is that the beginning of your film is in a different format (ie interlaced/whatever) from the rest -- you have a hybrid video, but more importantly, MeGUI is not picking it up. I am especially interested in such a video since I am working on a slightly better detector in the Avisynth forum. Anyway, posting exactly what MeGUI says on the analysis of the two different sections could give a lot of insight into the problem (probably enough to recommend and Avisynth script that works).

I would also really appreciate it if you could keep the original for a little while, so that you could try out my new program on it (later, when I have finished it).

Thanks,

berrinam

[markrb]

I may have found the reason for the jerky video in the beginning.
If I look at just the cut section it is reported as 29.97fps, but if I look at the whole video it is reported as 23.97.
It runs much smoother in the cut video at 29.97.
The really choppy video is the 23.97.

The interlaced sections appear to be only in the area that is reported as 29.97.
Is it possible that these are two different frame rates or is it more likely that Megui is confused and it really is 29.97?
Should I add a line to force 29.97? If so do you remember what it is?

Mark

[markrb]

I just did some further testing and it seems to confirm my belief.
In MPC the AVS script with no assumefps line is running at 23.97 according to MPC options screen.
If I play the VOB in MPC it runs at 29.97.
I am going to try the encode with assumefps(29.97) and see what happens.
If you need a copy of the VOB let me know where I can send it.
A whole section is 1gb, but I can probably chop it. However I do not know how that will affect detection.

edit:
I am starting to think that maybe MPC read the 29.97 because of Pulldown.
In any case I will see if it worked in a couple of hours.
At least playing the AVS in MPC looked better.

Mark

[markrb]

No go the video was badly out of sync, like I feared.
It may have looked better, but then again with the faster framerate I may have just not noticed it.

Mark

[foxyshadis]

You have to do one part at 30 and the other at 24, or that'll happen. Encoding both separately to mp4 or mkv and joining would work (no such luck with avi); most commonly you'd use TFM/TDecimate, which MeGUI will recommend when it detects hybrid sources, but apparently this opening is too short and falls under the hybrid threshold.

[markrb]

After further looking I am now testing dgbob as the deinterlacer and if the avs script is any indication it may have a decent chance.

If not then I will do what you suggest and cut the video or if I can just live with it. It looks like it's just the first 10 seconds or so.
I am doing mkv BTW.

What would I use to join the mkv video and can I do that before I mux so I can mux as a whole instead of two seperate muxes and then join?

Mark

[foxyshadis]

You can append in mmg (mkvmerge), in fact you can mux and append at the same time; just remember when adding your second video to use append and not just drag it in. If it's only ten seconds at the beginning that may well not be easier to integrate TIVTC's hybrid handling into the workflow.

You probably won't get great results with dgbob, doing the whole video at 30p will drag overall quality down and probably cause jerkiness.

2Kget =p

[berrinam]

You have to do one part at 30 and the other at 24, or that'll happen. Encoding both separately to mp4 or mkv and joining would work (no such luck with avi); most commonly you'd use TFM/TDecimate, which MeGUI will recommend when it detects hybrid sources, but apparently this opening is too short and falls under the hybrid threshold.
Either this is the problem or automatic force film is being triggered. Either way, the thresholds are stuffed up.

[markrb]

Using Nueron2's dgbob it came out perfect.
I did not have to mess with the framerate at all.

I have no idea why this filter worked and nothing else did.
It even plays better then no filtering in the opening scene.
Audio is in perfect sync.

Mark

[markrb]

Perfect may have been a bit much.
It's not choppy at any point, but the other eps do look a little sharper.
I am trying it the way you mentioned now. The first 8 seconds as one encode and the rest as another and then I will try and merge them.
If this works great if not I can live with the other encode, but hopefully this is the only episode like this.

Mark

[berrinam]

Wow, it's only 8 seconds? Sounds a lot of work for such a short amount..... I understand, though: if it can be done right, then it must be done right:D.

[markrb]

To quote part of my first post:
"I can probably live with it, but it bugs my sense of perfection. In other words I can be anal."
You have no idea how true that is.

The video when done as two looks great, but I am fighting with the muxing.
It seems the cut was not great and because of this the audio is out of sync.
I am continuing to mess with it (new cuts, new encode, etc...). Some year I will get it or give up.

Mark