mpeg-2 encoding problem

[Rick Mac]

Lunchbox,

I looked at the mpegs and jpg that you posted and as you say there is a diiference in what I would call chroma saturation which is perhaps caused by an increase in contrast.

Since your rendered mpeg file looks the same as your source video when it is pulled back into Vegas, that tells me that the mpeg encoder is giving you a accurate mpeg render. I have got to then ask myself what is happening in DVD Architect.

I would be curious to have you author a small test with another authoring program maybe Nero or such. If that gives you an accurate playout then we know our problem is within DVD Architect.

I must admit this one has me a bit baffled. I have not run into this myself. In fact I have used Vegas and Architect now for about 5 years and have never seen this happen. I’m not saying you don’t have a problem here, I’m just saying I have no ready answer for you other than to go thru the process of elimination my dear Watson.

How about trying an author in another app and let us know what happens.

Regards, Rick.

[Greg Mcdonald]

Rick,

So I pulled the 2 .mpg files output from Vegas into Nero to make standard DVD files and the results are the same. The output made from the file where I made no adjustments has the increased chroma saturation/high contrast and the output made from the .mpg where I reduced the contrast by 15% looks correct like the source file.

This “VTS_01_1.VOB” file is the output file made from the .mpg file where no adjustments where made to contrast:

https://icorptv.com/assets/multimedia/NeroFromNoAdjustmentFile/VTS_01_1.VOB

This “VTS_01_1.VOB” file is the output file made from the .mpg file where the contrast was reduced by 15%:

https://icorptv.com/assets/multimedia/NeroFromMinus15Contrast/VTS_01_1.VOB

Once again if you open these up in a DVD player like Real, PowerDVD or Nero Showtime and compare these to the frame grab from the source file, the .vob with the lowered contrast looks like the source while the other one has the increased sat/contrast.

And just to be sure, I burned these 2 outputs to DVD and watched them on a TV set with the same results.

It has to be the MainConcept mpeg-2 encoder, which is the DVD encoder in Architect also. I also pulled the original .mov source file directly into Architect and rendered to DVD and the filed showed the same increased chroma sat/contrast that the .mpg file output from Vegas has.

I’m at a loss. Do you know what the next process of elimination step would be?

Greg

[Rick Mac]

[lunchmoney] “I’m at a loss. Do you know what the next process of elimination step would be?”

I’m at a loss as well. It seems to make no sense. Your rendered mpeg file looks the same as your source footage within Vegas timeline, but outside of Vegas it does not.
I’m stumped. Thought we would find our answer within the authoring phase. But that did not pan out.

Sorry I could not help you solve this.

Regards, Rick.

[Greg Mcdonald]

Rick,

Thank you for taking the time to look into it.

At least I do have the work around of lowering the contrast every time before I output to DVD. Then putting it back to zero before I do any other type of outputs. That’s a total pain and it’s not something that I should have to do in order to get a proper DVD output but it does work.

Just means I most definitely will not be buying the full Vegas program. I thought it might be an option for certain jobs but I’ll be sticking to Final Cut Pro.

Greg

[Edward Troxel]

There *HAS* to be something else going on! It seems odd that YOU would be the ONLY person to have this issue if there was a bug. Maybe the source of the video? Or some effect you’re adding in Vegas that we haven’t heard about yet? Or something else… but there’s SOMETHING different here.

Edward Troxel

[Jerry Waters]

Could anyone be screwing with your computer? As in a “joke?”

[Gern Blanstein]

Maybe this topic should be refreshed…

There does seem to be a problem with the MPEG-2 encoding. I encountered the same scenario trying to render a starfield. Only the brightest stars survived the encode.

I have used MainConcept’s stand-alone encoder for years and never noticed this problem.

[Greg Mcdonald]

Hey Gern,

Well I’m glad someone else had this problem – mind you, I’m not glad you’re having this problem, I’m just glad to hear it wasn’t just me.

The only thing that fixed the problem for me was to stop using Vegas and to just stick to FCP. It’s a better program for my needs anyway.

Greg

[Matt Jones]

Yeah I’ve been having the same problem. I found that encoding to WMV gives a video without the contrast issue. I then use a free encoder called “Super” to convert the wmv to an mpg which doesn’t have the contrast problem.

It seems the MPG encoder that comes with vegas (even the pro version which I have) is basically garbage.

[Eric Lewis]

Lunchmoney, any soulution yet?

I’m a little late here to the party but had to chime in as I’ve been scratching my head for a couple of days on a VERY similar issue with no real (easy) solution yet.

My problem isn’t directly related to Vegas, but I thought my observations may help narrow the issue down.

I seem to be having the exact opposite problem from lunchmoney

I have a large quantity of analog video captured with an ADS Pyro AV link Pro into uncompressed AVI, and I’m attempting to compress it down to reduce storage space.

I’m using Vegas 6 for editing, but I am using TMPGEnc 2.5 to do my encoding to Mpeg 2 (due to Vegas’ disappointing lack of a batch converter) When using the DVD NTSC settings, I get a resultant LOSS of contrast when I view the file – either in WMP, Power DVD or importing back into Vegas(using Vegas’ built in waveform scope it appears to be about 13-15% loss)using the scope settings of 7.5 IRE setup and Studio RGB both OFF, my once 0% black backgrounds become ~6% gray.

When I use Vegas (and the built-in Mainconcept 2.0 encoder) to encode the file it appears fine. I can’t find any info on the encoder that TMPGEnc uses (I guess propiatary)

I’ve tried tweaking just about everything in the codec with no change – including the buit-in Contrast/brightness filter – nothing will lower the black level back down to where it is in the original.

Sorry this doesn’t directly support your issue but it does demonstrate that there are some re-encoding issues with MPEG that affect contrast levels…now if we could just find out what they are!