Thank you very much, I am using suggestions just now.
Why Vegas videos have flicker?
Is the flicker a defect of Vegas videos?
have Adobe After Effect videos flicker problem too?

No, no and no.

The problem is that interlace video must have no more than around 70% of the full raster resolution or you will get exactly the problem you are seeing. It's called several things including line twitter. Even though your video is progressive it can only be displayed on CRTs as interlaced.
To wrangle this and other problems video cameras employ an Optical Low Pass Filter. Plus when recording interlaced video they use line pair averaging. This reduces vertical resolution and also noise. As a result all else being equal the same camera is around 1 stop more sensitive in interlace than progressive.

When you create images using CGI or use hires stills you need to ideally do the same processing as the camera. Also if you shoot progressive HD and downscale to SD you may need to wrangle this exact same issue. Getting flicker free SD 50i from the EX1's progressive modes is not a simple task. In fact from what I see in OTA SD broadcasts it's no trivial task with the most expensive scalers money can buy.

Apart from the flicker problem you can also hit a problem with aliasing and the Nyquist limit. I've had one still image that would literaly blink at around 1Hz in 50i and stopping it without killing the resolution was not easy. Even more of a problem is building the very best low pass filters that wrangling this requires produces code that takes forever to run, literaly the ideal solution would never render which is probably why in a camera the issue is still dealt with using an expensive optical filter rather than digital processing.

Bob.

If by flicker you actually mean aliasing/moire (reduce interlace flicker will reduce the normal type of interlace flicker), then the solution is:

Add a gaussian blur filter to your event.
Click the pre/post triangle in the bottom left hand corner of the video FX window. Read the manual if you can't find it.

You've tried a lot of the standard remedies. Someone already linked to that post I did years ago about the list of ways to reduce flicker in still photos that you animate in Vegas. As I mention in that post -- and I want to re-iterate here -- reducing resolution of the still photo outside of Vegas is probably the most effective thing you can do. So, estimate the maximum zoom for a given photo. Multiply this by the project resolution and then add 20-30%. Then, in PhotoShop (or whatever you use to edit still photos) reduce the resolution to this amount (save your original!!). Use that reduced resolution version. Do a quick test by rendering just a handful of these altered pics, author a test DVD on an DVDRW disc, and play it back on your PAL monitor. See if things are better.

I have found that this almost completely eliminates the problem, although as Bob (farss) points out PAL may have more problems in this area because of the AL part of PAL.

John's solution sounds like a better idea than the gaussian blur approach I suggest. It would be faster to render.

The Phase Alternate Line trick isn't that much of an issue these days, if it was I'd still be editing on 8 frame boundaries or whatever that horror was that had to be dealt with.

The flicker and aliasing problem is dead easy to fix. The big question is how to fix it while doing the absolute minimum amount of harm to the image and at the same time producing the very best perceived image on the screen whilst keeping in mind that PAL and to a greater degree NTSC is incredibly low resolution.

Our perception of video images is a very difficult thing to measure quantitatively and yet easy enough to see. Would you take a still image at 480x720, blow it up to 30" and hang it on the wall in your living room, I doubt it. And your that's what you have in your living rooms in NTSC land on your TV and it looks just fine. Indeed our 720x576 looks at tad better but I still wouldn't buy a DSC that was only 720x576!

Try this simple test. Take a good or even the most expensive SD camera and very very slowly pan a wide shot of a landscape. Look at it on a monitor. Compare how it looks to any still displayed on the same monitor. You can feel the difference immediately, why?

I suspect the answer is that a sequence of moving images contains more information that our eyes and brains can use than any single frame. Good software upscalers such as Topaz can extract that information much as we can. All of this goes back to something a client of mine taught me, he's very technically challenged so it took me a while to take on board what he was saying. Never have a static image if you're working with stills. You only need the very slightest zoom or pan, just a few pixels worth over the duration of the shot will do the trick. Of course this will not work if you've already downscaled your stills to the target resolution.

The downside to this is you will very likely have to wrangle aliasing and line twitter problems and probably by hand which as I've experienced can be inordinately time consumming with lots of stills.

Bob.

Dear friends,
I thank you very much for attention.
I cannot reduce pictures size because I want compile both a PAL version and a Blu-ray version of my projects, so I tried your suggestions but without size reduction I was not happy of results: the "Reduce interlace flicker" seems to do nothing and the "Gaussian blur" waste the quality of small details. I do not understand because Sony do not fixed a such serious problem from the wonderful Vegas.

The methods we were describing are only for use when you downscale for SD. HD 50i can have much higher resolution than SD without getting twitter problems. What matters is the ratio of actual vertical resolution to the number of vertical pixels.

So for HD 50i the limit is around 800 lines. For SD 50i around 400 lines. Clearly an image with 400 lines vertical resolution is way too soft for HD.

Bob.

I do not understand because Sony do not fixed a such serious problem from the wonderful Vegas.

Hello Skywalker. You should read all the help you get here, and you need to try it. It is the only way to get decent quality video from still pictures. If I was doing both HD and SD I would use two different images for the process if I could not get it to work with a single image. It depends a bit on the image in truth.

Now, an important point: This is not a Vegas issue. This is an issue with any video editing software since it is a general issue with going from progressive stills to interlaced moving images. There is stuff out there that costs tens of thousands of dollars and more and those tools have exactly the same issues as Vegas. Some of them are better, others are not.

So, you don't have a choice, try the advice given in this thread. It will take time and it will not be easy to get it exactly the way you want.

You might notice that there are some areas of the pictures that are more prone to this flickering than others. Run a test and see. Then apply a mask on that area only in Photoshop and apply the blur only where the problem areas are. That might work, but you're going to have to test it.

Dear friends,
thank you for your patience and professionality.
To use "Reduce interlace flicker" checkbox have I to set every video track to "Field order"=Progressive scan both on PAL and BD projects? and what is the right set to the "Field order" of every project?

Thank you again

The field order of your media MUST match the actual field order of that media. Thus, still photos should show as progressive, and PAL 50i SD video should show as interlaced bottom field first and HDV 1080i video should show as interlaced with top field first.

Did you read everything in theStill photo flicker reduction?

In that, you will find that if you do use Gaussian Blur, you only need to do so in the vertical direction. Set Horizontal to Zero. Also, the vertical amount should be the smallest setting allowed which, from memory, I think is 0.01.

Dear friend,
excuse me but i do not understand. I explain again: I have many 3D motion projects, both PAL Widescreen and Blu-ray, where I used only pictures of different sizes. On every project I see the "Reduce interlace flicker" checkbox on every track. I would like to know if, to use the checkbox, I have:
1) to set the "Field order" property of every track to progressive
2) to set the "Field order" property of every project to progressive
3) to leave the "Field order" properties unchanged to their default values both on tracks and projects
Many thanks

When you create a project you use a template, HDV, PAL Wide Screen etc. Leave the project Field Order as Vegas sets it. It is correct.

Then you add media to your timeline. Typically Vegas sets the Field Order correctly depending on your media. One exception is still images, Vegas will set Field Order of still images to the field order of your project. Change them to Progressive, and "Reduce Interlace Flicker".

I didn't think you could set the Field Order of a track, but if you can, leave it the same as the project I would guess. I think you can only set it on project and media though.