Simple guide: VOB to AVI to MPEG2

[Cunhambebe]

Everytime I try to convert VOB to AVI with DVD2AVI, the final result is excellent. On the other hand, as soon as I edit the AVI file and re-render as MPEG2, I get some bandings. Take a look at this exemple:



- Single AVI files can be rendered with TMPGENC using its inverse telecine option, works great (no banding anymore).
- these MPEG files, previously rendered with TMPGENC (AVI to MPEG/m2v - inverse telecine), if edited on Vegas timeline and re-rendered again as MPEG files, bring the problem back again (banding).
- Many edited AVI files (ex, on Vegas timeline) that make a whole project, if rendered this way as MPEG or m2v in TMPGENC, (from Vegas timeline tru Debugmode), even using TMPGENC's inverse telecine, give the same bad result = banding.

Can anybody helpme please?
Thanks in advance.

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[Capmaster]

The banding is caused by the transition from one color to the next. It's common when you reduce the color pallette of an image or video. It's caused by a jump over more than one color to get to the next nearest one and happens when you reduce the pallette from millions of colors to 16K colors or 256 colors, for example.

Check your settings to see if you're limiting your colors in one of the steps.

[Cunhambebe]

Thanks for taking time to respond. I guess this is a difficult task (where to find settings for this) when you're a newbie, but I'll try. I guess there's something wrong somewhere when I re-render this AVi to MPEG. Have you tried it yet? What's the outcome?

[gitreel]

why would you rerender to mpeg2 when it was mpeg2 to begin with? I am confused. That is an unnecessary step

[Capmaster]

Thanks for taking time to respond. I guess this is a difficult task (where to find settings for this) when you're a newbie, but I'll try. I guess there's something wrong somewhere when I re-render this AVi to MPEG. Have you tried it yet? What's the outcome?

I don't use DV so my material is in the MPEG form already. I can't advise you on that step. Just look through the user settings and check for an option called "optimize pallette" and turn it off, or anything with "colors" in it. Make sure you leave the original pallette alone.

[Cunhambebe]

thanks to all who took time to respond:

- why would you rerender to mpeg2 when it was mpeg2 to begin with? I am confused. That is an unnecessary step... (I do agree, on the otehr hand, if I follow these steps: TMPGENC>MPEGTOLLS>DE-MULTIPLEX VOB FILE>MULTIPLEX>MPEG - same result: banding. Although you might think it's an unecessary step (VOB to AVI, edit, then back to MPEG again), some say that's the right way to edit the file with premiere (or Vegas in my case).

Capmaster wrote:

I don't use DV so my material is in the MPEG form already. I can't advise you on that step. Just look through the user settings and check for an option called "optimize pallette" and turn it off, or anything with "colors" in it. Make sure you leave the original pallette alone.

-now I am confused....aren't all AVI, MPEG the same, I mean, DV? I can't find the pallette, don;'t even know where it might be, give me some more help please.

One more thing: I've checked the AVI's rate: 23,976 fps. My project is for DV 29,970. Couldn't it be the frame rate?

Thanks!

[Gazorgan]

AVI, MPEG, DV are all quite different. Going from one to another isn't neccasarily lossless. You would be much better off working with the antive MPEG/VOB (MPEG's and VOB's are interchangeable, lossless conversion is easy) and not converting.

Nowhere in your post do you specify the parameters of the intermediary AVI. That is, you converted to AVI, what codec? Frameserving with DVD2AVI isn't the same thing.

What you are experiencing is fairly common. It can happen when you hit a 16-bit color scheme (some configurations DivX/XviD will do this). It can also happen changing your video from TV ready to computer. You TV can't display all the colors your computer can, but this usually shows up in black scenes.

It can be from too low a bitrate also. Normally you see macroblocking, but if your shaving bits in a VBR pass, the background is a big fairly static space to steal from.

[Cunhambebe]

Gazorgan, thanks for you help, but could you please tell me, step by step, the way you do this VOB to MPEG? Let's see what I usually do:

Gazorgan wrote:
You would be much better off working with the antive MPEG/VOB (MPEG's and VOB's are interchangeable, lossless conversion is easy) and not converting.

-I've tried this: TMPGENC>open VOB>DE-MULTIPLEX>MULTIPLEX> RESULT = same banding.

Gazorgan wrote:
Nowhere in your post do you specify the parameters of the intermediary AVI. That is, you converted to AVI, what codec? Frameserving with DVD2AVI isn't the same thing.

a)Parameters for avi: uncompressed.
b)2 ways to get to the final avi:
1.tru DVD2AVI, directly choose, save avi as
2.frameserving, save project as, vfapi, Vegas timeline = final avi uncompressed (or even using huffyuv).

Gazorgan wrote:
It can also happen changing your video from TV ready to computer. You TV can't display all the colors your computer can, but this usually shows up in black scenes.

Could it be, for instance, choosing a wrong setting in DVD2AVI (TV scale/ PC scale)?

[Cunhambebe]

Sorry, I've got to make a correction here:

Gazorgan wrote:
You would be much better off working with the antive MPEG/VOB (MPEG's and VOB's are interchangeable, lossless conversion is easy) and not converting.
-I've tried this: TMPGENC>open VOB>DE-MULTIPLEX>MULTIPLEX> RESULT = same banding. (CORRECTION - IN FACT, THE OUTCOME IS PERFECT, BUT AS SOON AS YOU EDIT THIS MPEG FILE AND RE-RENDER AGAIN, THE BANDING IS BACK).

Now, there's only one more test to make with DVD2AVI - video>YUV>RGB>TV SCALE

[Cunhambebe]

? ? ? ?

[Gazorgan]

BUT AS SOON AS YOU EDIT THIS MPEG FILE AND RE-RENDER AGAIN

Is the problem. Don't re-render. Are your rendering in TMPGEnc or what? You want to stay in TV scale, if that's your final product.

Let's start over. Instead of telling me what's not working, tell me what you are trying to do? Your method seems to have an issue, so let's re-think the method.

[Cunhambebe]

Thanks!

Firstly, the purpose of DVD2AVI seems to let the created AVI being edited with Vegas or Premiere. LEt's take the following exemple that shows clearly what's happening.
It's a simple thing I got a VOB file (from a commercial dvd - movie), just a small part of it, about 6 seconds.

1.Open DVD2AVI>Open the VOB file>Choose Video:
Video options:
a)iDCT algorithm 32-bit SSE MMX
b)Field Operation>Forced Film
c)Color Space: RGB 24 bit (I've also tried YUV 4:2:2)
e)YUV->RGB: TV or PC scale (doesn't matter)

2.Save project as (name)

3.Open VFAPI, create fake avi.

4.Open Vegas, open fake avi, render as avi uncompressed or huffyuv.

result = excellent AVI (Important: AVI properties = 23,976 fps IVTC FILM)

Open this AVI on Vegas Timeline, edit, pan and crop (match output aspect and cut off back edges). Important: project properties (on the timeline) = NTSC DV 29, 970).
After the editing process, render again as MPEG2 DVDA (for DVD architect) NTSC video stream, best resolution.

Final quality = the picture above (lots of bandings)

that's it.
Thanks for your help.

[Cunhambebe]

????

[pacmania_2001]

I know that sometimes it can be antsy having to wait for an answer but please wait at least a day to bump your questions.

[Cunhambebe]

C'mon guys....
I've found out I can do some dithering with the video. It may "covers" but doesn't fix the problem. I'd like to know what's happening with my MPEGs made of AVIs or demuxed files, both comming from VOB files.
Some users said that in some systems, due to the incompatibility of some of the codecs installed, this bad image can occurs. Any idea, please?