DivX encoded movie w/erratic playback

[yossarian82]

Hi, encoded a movie in DivX 5.05 and i got a weird problem that hasn't happened with any of my other movies. Basically the movie isn't playing smoothly, it seems to pause at regular intervals (say every second or so) but not stop completely, just slow down slightly then go back up to normal speed then slow down again 1s later then speed up again etc etc. a bit like if you were playing a video tape and tapping your finger down once every second on the tape to slow it down regularly (but not holding it down, just tapping it). hope that's clear :P

I'm thinking perhaps something to do with the player trying to keep the visuals in time with the audio b/c something has gone wrong with the encoding? anyway i have other movies encoded with exactly the same methods (DivX 5.05 for the visuals, mp3 for the sound) that don't have the same problem...

thanks for any help...

[manono]

Hi-

I'm thinking perhaps something to do with the player trying to keep the visuals in time with the audio...

Yes, that's the first thing I thought of also, as I was reading your post. You can test this easily. Take the video without audio included (or make one by direct streaming the movie without the audio) and play it. If it plays smoothly, then it's almost certainly the audio interleaving, or something wrong with the audio itself. There's a fair chance that it can be fixed by direct streaming the audio and video with VDubMod or NanDub with default interleaving settings. If not, maybe reencode the audio.

[yossarian82]

thanks, i'll try that

[yossarian82]

hmm ok so i ripped a section of video from the movie and encoded it, in Vdub, with 5.05 sans audio. and... still getting the erratic playback! the thing is it's not like a speedup, which is what you'd expect perhaps from an audio sync problem... it's more like it's stopping every second or so, for a fraction of a sec. i'm really stumped now :/

i've tried looking for errors or whatever; nothing. i don't *ahem* have the source file anymore so re-encoding from source is not an option. so... perhaps there's a filter or something i can run it thru, in Vdub, that'll smoothen the video out? desperate now :(

[Tuning]

I think this is the same problem I had encountered.That is illegal PAL -> NTSC conversion problem.Look here how i overcame it:here (http://forum.doom9.org/showthread.php?s=&threadid=63250)
You need to use RePAL filter.Look to the posts made by manono.He was the helping hand.



-Tuning

[SeeMoreDigital]

Hi yossarian82,

Have you put something new on your PC, like the DivX player 2.5. Or did you upgrade to DivX 5.1.0 and then go back to 5.0.5!

I only ask because I've just installed DivX 5.1.1 beta1 (admittedly on an 800MHz P3) but now all my old DivX encodes are choppy!

Cheers

[manono]

Hi-

You haven't said whether you're PAL or NTSC. If PAL, they sometimes convert from NTSC by adding one frame in every 24 (one every second). If you open the .avi in VDubMod, you can check to see if every 25th frame is a duplicate.

If you're NTSC and IVTC'd, then Tuning may have the answer (except it's not illegal, just stupid :)). Or maybe it's interlaced, and you shouldn't have IVTC'd at all. Or it may be something different, as SMD's implying. Have you tried different players or different decoders (ffdshow) to try and duplicate the problem?

[SeeMoreDigital]

I forgot to mention.

If you do find that you have two (or more) DivX codec 'config.exe' files. You will have to disable 'post-processing' in the 'Decoder Properties' in one of the 'config.exe' files!

Cheers

[yossarian82]

Ok, just to clarify - the movie is encoded from a PAL source. i'm using the normal FPS rate of PAL (i think its 25fps), however this duplicate frame thing does sound interesting...

it seems a little too technical for me tho, i've no idea what half this stuff is going on about...? how do i remove the duplicate frames without messing up the fps rate?

also i'm using ffdshow atm i think... i'll check and see if the prob duplicates with other playback filters

thanks for your help

[SeeMoreDigital]

Originally posted by yossarian82
Ok, just to clarify - the movie is encoded from a PAL source. i'm using the normal FPS rate of PAL (i think its 25fps)..... In most cases PAL DVD's are encoded at 25FPS and NTSC DVD's are encoded at 30FPS.

So when generating encodes, you should stick to the same framerate as the source!

Cheers

[yossarian82]

naturally - i realised that:P

anyway i checked the encode, and it appears (along with a few other movies that i encoded previously) that there are duplicate frames and that they are causing the weird jerks.

not all the PAL movies i've encoded have this error, just a few of them.

the strange thing is the dup frame appears to be every 12th frame... and that's for all the movies i checked that had the error. so basically:

-is there anything i'm doing in my encoding that is messing up the encode?

-is there anything i can do to remove those dup frames in order to make the movie play normally?

thanks for your help

[SeeMoreDigital]

Hi yossarian82

I suppose there may be tools available (I don't know of any myself) but personally I think it would be far quicker and less frustrating to encode the movie again from scratch!

Cheers

[Soulhunter]

Just a guess...

Could this source originally have "film" fps rate (24fps) ???

Because he said its every 12th frame... (2x12=24->25fps) :confused:

Had never such content, so I don't know if something like this exist...

But as I said, Its just guessing ! ;)

Bye

[manono]

Hi-

Yeah, it's like I said earlier. They add one extra frame in every 24. They didn't add it as a single frame, but as 2 fields, 1 every 12 frames, in order to make it play more smoothly. So you didn't see a duplicate frame every 25 frames, but a sort of duplicate frame every 12 frames. It has to be fixed during the initial encoding. It's too late to fix the .avis as the dup fields have become blended frames. I would guess the .avis are blurry messes. In the future:

Telecide().Decimate(25)

Read this (http://www.doom9.org/ivtc-tut.htm#PALTheGoodTheBadAndTheUgly). Because the field order is constantly switching, it's better to use the older Decomb 4.10b which can correct it (and upon which that tutorial is based). The newer 5.x versions require you to set the field order. From that tutorial:

Some DVDs switch between real progressive and field shifted progressive. If this happens twice every second then you have a DVD with a field added every 12 frames to keep the time constant. Now, assuming that you have established that you have a progressive DVD, either by adding Telecide or by turning Swap Field Order ON/OFF, then we proceed to look for doubled frames. If they appear, they should only appear once every second, and in this case you must add Decimate(cycle=25) to your final script.

[SeeMoreDigital]

Yes, I know exactly the problem yossarian82 is experiencing. And it is exactly what manono has described.

I can replicate it quite easily by spinning an NTSC DVD and forcing my Xcard to output a pure PAL signal - instead of PAL60!

I have to say some NTSC sources look better than others when forced into pure PAL. But it has its uses, all the same, when backing up NTSC sources to PAL VHS tape.

It's going to get really interesting soon when more and more 24FPS (film speed) equipment makes it into the 'non professional' market place!

Cheers

[DigitAl56K]

If you're using DVD2AVI either uncheck Force Film if its checked, or check it if it isn't.

[jggimi]

Force FILM should ONLY be used on NTSC sources at 29.97 fps. And then, only with sources with proper MPEG-2 flags. This content is 25fps. Force FILM should NOT be used.

[yossarian82]

Yeah, it's like I said earlier. They add one extra frame in every 24. They didn't add it as a single frame, but as 2 fields, 1 every 12 frames, in order to make it play more smoothly. So you didn't see a duplicate frame every 25 frames, but a sort of duplicate frame every 12 frames. It has to be fixed during the initial encoding. It's too late to fix the .avis as the dup fields have become blended frames. I would guess the .avis are blurry messes.

What do you mean by that last sentence? The .avi movies that have this problem are fine, graphics-wise - it's just that every twelfth frame is a duplicate of the previous one. They're not blurred messes...

Is there really no way to fix the encoded movies? How hard can it be to remove every 12th frame?

In the future:

Telecide().Decimate(25)

WHat does this mean? :(

Read this (http://www.doom9.org/ivtc-tut.htm#PALTheGoodTheBadAndTheUgly). Because the field order is constantly switching, it's better to use the older Decomb 4.10b which can correct it (and upon which that tutorial is based). The newer 5.x versions require you to set the field order. From that tutorial:

Some DVDs switch between real progressive and field shifted progressive. If this happens twice every second then you have a DVD with a field added every 12 frames to keep the time constant. Now, assuming that you have established that you have a progressive DVD, either by adding Telecide or by turning Swap Field Order ON/OFF, then we proceed to look for doubled frames. If they appear, they should only appear once every second, and in this case you must add Decimate(cycle=25) to your final script.

So presumably i'm removing the doubled frames, but what programs do i use to do this? And at what point? I use flaskmpeg not DVD2Avi also...

confused :confused:

[manono]

Hi-

Where you been hiding, yossarian82? We've been carrying on without you. :) Well, I made a couple of assumptions that maybe I shouldn't have made. I was assuming that there was one duplicate field in every 12 frames (or 24 fields), after which there was a field order switch. That's not uncommon with PAL DVDs. And I was assuming that you had to have deinterlaced the whole thing to get rid of the interlacing. Guess I was wrong. Not the first time. Sorry.

I'm having a little trouble imagining how such a thing can even be on a PAL DVD. But to fix it, you'll have to reencode, either the .avi, or from the original DVD. In this case you'll need:

Telecide(order=1). Decimate(12).

I haven't used FlaskMPEG for years, so I can't help you with it. Maybe somehow it created the duplicate frames. If you use DVD2AVI and AviSynth to frameserve into VDubMod, then you'll learn about such things. I might recommend using Gordian Knot for this in the future.

[SeeMoreDigital]

Hi again yossarian82'

Can you run your file through an application like Gspot (http://www.headbands.com/gspot/download.html) and post the results please?

This is all very odd!

Cheers

[yossarian82]

ok will do...

perhaps i should clarify my encoding procedure a bit:

-rip DVD source to HD via Smartripper
-encode ripped files to DivX/MP3 using Flaskmpeg

anyway i'll get back to you once i've used this Gspot thing, thanks for your help guys

[yossarian82]

Gspot edit of the movie:

http://www.deviantart.com/view/3712579/

I have a segment of the movie available if anyone wants to look at it, i currently don't have anywhere to host it but i can email it; it's only 1.5 megs.