Anyone figured out how to get Vegas to do a good dissolve?

craftech wrote on 3/8/2004, 5:40 AM

I have a musical I shot which will absolutely require a common transition which I have avoided like the plague since Vegas 2.0........the dissolve.
I generally do cuts only or fading to or from black, but I have no choice for this as the director put the chorus way off stage left requiring a second camera just for them.

Problems I have had in the past with dissolves are:

1. Flash frames in the middle of them

2. Blank frames in the middle of them

3. Less than smooth transition

4. Havoc wrought when trying to render videos which include them to Mpeg 2 for a DVD. Artifacts, etc.

Anyone have the magic formula?

Thanks.

John

PS: Please include what should be checked and unchecked in the various settings. I would really appreciate the time that would save in experimentation and reposts.

Comments

Former user wrote on 3/8/2004, 5:45 AM

The only problem that you have listed that I experience is the MPEG artifacts. But I see this in other programs as well. Those little pixels can't decide what value they are supposed to be during the dissolve, and thus you get a little noise.

Otherwise, all of the dissolves I have done have been smooth and clean. Do you get this in all of your dissolves?

Dave T2

Chienworks wrote on 3/8/2004, 5:45 AM

Hmmm. Please describe what you mean by dissolve. Are you talking about a crossfade? If so, overlap two clips by the length of the effect you want. That's all there is too it. I always get a perfect crossfade.

Then again, i never used Vegas 2, so i don't know if it was a problem back then or not. Vegas 3 & 4 do this perfectly.

rebel44 wrote on 3/8/2004, 5:47 AM

I do not know about v2, but in v4 it is as smooth as possible. Just adjust the timing.

craftech wrote on 3/8/2004, 5:47 AM

I have gotten "flash" frames. Frames from somewhere else in the video momentarily flashing on the screen. Or blank black frames sometimes.

John

craftech wrote on 3/8/2004, 5:48 AM

How much do you guys overlap the split sections for a dissolve? And what do you do with the audio? Do you have the video sections on different tracks? I generally put all the video on one track. Maybe that's the problem with the flash frames.
etc.

John

Chienworks wrote on 3/8/2004, 5:54 AM

I just drag 'em. Place them on the same track and drag the one on the right over the one on the left. Audio will crossfade too.

If consistant audio timing is a consideration and you merely want the video to dissolve to a different view, you can replace that section of the video track with the take from the other camera as if you were doing a cut-only transition, then drag (simple drag, not Ctrl or Alt-drag) the edges over the adjoining clip. The farther you drag, the longer the dissolve.

If you want to do a two-track method, place the alternate take on the upper track, then use simple fades at the beginning and end. This will cause a crossfade into and out of the alternate view.

farss wrote on 3/8/2004, 6:07 AM

Must say I've had maybe one problem witha dissolve. Turns out I'd left like a 1 frame fragment of video sitting on the track casuing a "flash".

As has been noted mpeg compression and dissolves are problematic, very slow dissolves may work better. Trick is to get the minimum amount of change between each frame. Of course if you had the same tools as the pros then the dissolve would be encoded at a higher bitrate.

SonyEPM wrote on 3/8/2004, 6:21 AM

I have never been able to repro this mysterious flash frame problem some of you are reporting. Just a guess, but try setting ram preview allocation to zero- still see flashes?

craftech wrote on 3/8/2004, 6:31 AM

Thanks for all these suggestions. I'll try them all today.

"you can replace that section of the video track with the take from the other camera as if you were doing a cut-only transition, then drag (simple drag, not Ctrl or Alt-drag) the edges over the adjoining clip. The farther you drag, the longer the dissolve."

Won't that throw off the lip synch from the singers? The views are close up.
Also, SONYEPM, do you have a solution to the artifacting problem for Mpeg 2 renders?

John

TheHappyFriar wrote on 3/8/2004, 7:34 AM

I've never had a problem with disolves (I use them A LOT). Could it be your default fade/disolve type? If you have the "slow then fast" fade/desolve for both, when they hit the 1/2 way point in the disolve neigther video is faded out 1/2 was or less. Hence, the colors will be added on top of eachother and will appear brighter (in most cases). However, if you use a linear fade/disolve when 1/2 way through the disolve is reached each video will be 50% faded, total of 100%. :)

If you had the "slow then fast" fade/disolve, short ones will look like a flash. Try it. it's cooool. :)

I've never noticed any mpeg artificats after rendering (6.8mbs constant) but maybe it's cuz i mostly use vhs/hi8 footage and can't tell. :)

craftech wrote on 3/8/2004, 7:45 AM

I've never noticed any mpeg artificats after rendering (6.8mbs constant) but maybe it's cuz i mostly use vhs/hi8 footage and can't tell. :)
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I always use VBR. Been afraid to try CBR. Nearly everyone seems to favor VBR. Think that's a factor?

John

Chienworks wrote on 3/8/2004, 7:55 AM

If anything, VBR should handle disolves better than CBR.

craftech wrote on 3/8/2004, 8:06 AM

If anything, VBR should handle disolves better than CBR.
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Kelly,
Are you getting artifacts in your dissolves when rendering your Mpeg 2?
John

bstep1 wrote on 3/8/2004, 8:37 AM

Everytime that I have had the flash frame (frame from another part of the video) appear, it has been when I pulled the end of the clip out for the dissolve/crossfade and inadvertantly pulled it past it's end which results in it looping back to the beginning of the clip and thus, the flash frame. Make sure you are moving the clips over each other or notice if you extend the clip past it's end - you will see a little indicator at the top that shows it is now repeating itself.

Chienworks wrote on 3/8/2004, 8:50 AM

I've never seen an MPEG file (or any other compresse format for that matter) that didn't have artifacts.

I guess the question is, how much artifacting can you have before it becomes objectionable. I'll do most of my "work for others" encodes at around 6Mbps average VBR. At this rate there are still a few small artifacts here and there. They appear in fades and high motion areas as much as in dissolves. They're especially noticeable in darker areas or along high contrast lines. However, i know what to look for and they stand out to my eyes. Other folks look at stuff i've encoded at 3Mbps and think it looks great.

Take a close look at a big budget Hollywood DVD frame by frame and i'm sure you'll be able to spot some artifacts there too.

craftech wrote on 3/8/2004, 8:56 AM

When one is watching a gifted soloist singing a balad on stage and the camera fades from the 4 member chorus (equally gifted) to the soloist in a slow dissolve with ARTIFACTS in it, it looks objectionable to everyone.
For up-tempo songs you can get away with cuts.

John

Chienworks wrote on 3/8/2004, 9:04 AM

John, have you tried doing a dissolve in Vegas 4 yet? Create a little 10 second long project, crossfade one video clip into another, render it VBR at 6Mbps average or so, and look at it. I think you'll find that Vegas 4 does a fine job. In fact, Vegas 2 probably handled the crossfade itself perfectly well; it was most likely the old Ligos encoder that was having troubles. Vegas now uses the MainConcept encoder instead and it's vastly better.

Remember that a crossfade (dissolve) is no harder for the MPEG encoder to work with than situations where the camera angle changes or the lighting changes or everyone moves or ... etc.

craftech wrote on 3/8/2004, 9:07 AM

John, have you tried doing a dissolve in Vegas 4 yet? Create a little 10 second long project, crossfade one video clip into another, render it VBR at 6Mbps average or so, and look at it. I think you'll find that Vegas 4 does a fine job.

Remember that a crossfade (dissolve) is no harder for the MPEG encoder to work with than situations where the camera angle changes or the lighting changes or everyone moves or ... etc.
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Kelly, I definitely will try everything suggested here and thanks for the help.
Much of my love for Vegas is directly related to my love of this forum and the people on it. I have to use dissolves for this so I will try everything to make it work. Who knows, maybe I'll be pleasantly surprised this time thanks to all of you.

John

roger_74 wrote on 3/8/2004, 9:13 AM

Actually, crossfades are tough for encoders. Hollywood gets away with it because of adaptive bitrates and low pass filtering.

craftech wrote on 3/8/2004, 10:00 AM

Adaptive bitrates?
Do you mean DTS which is is based on ADPCM, Adaptive Delta Pulse Code Modulation? This difference signal is encoded and quantisized to fit in the datastream. Normally ADPCM achives a 1:4 compression ratio. The home version of DTS is enhanced with additional algorithms. I am only familiar with adaptive bitrates as they affect the audio portion not the video portion.

John

TheHappyFriar wrote on 3/8/2004, 10:07 AM

I use CBR because I don't have DVDA and the burning program that came with my burner only supports up to 6.8 CBR (and of course they wouldn't tell me that outright. I asked tech support and they said they couldn't tell me. So I saved a couple of mpeg's the authoring program encoded and anaylized those files).

Also, try rendering a disolve that you know if screwing up to a new track (right above the actuatly disolve). Then render that part out. See how the encoder handles that.

jaegersing wrote on 3/11/2004, 1:40 AM

craftech wrote on 3/11/2004, 5:14 AM

I have seen the flash frames several times. Sometimes it is a blank frame, sometimes a frame from somewhere else in the video. ALWAYS, it has been in a project where I have moved clips around while the snap to frames toggle was set to OFF.

Richard Hunter

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Sonic Foundry/Sony tech support has never been able to reproduce this phenomenon. I wonder if they tried it as you described?

John

farss wrote on 3/11/2004, 5:54 AM

I've had the same thing happen more than once, but there's no great mystery to it. Singel frames get left lying around on the TL and end up inside dissoleves. Maybe a script that finds all clips less tha x number of frames could clear this issue up once and for all.
Once I pulled a single short segment of video out of a 90 minute program, I was wondering why it took for ever to render, well there was one frame left at the 90 minute mark. My own silly fault, not Vegas's.
The other thing to think about, during a dissolve or fade you are exposing the underlying 'nothing', by default that is absolute black which is outside legal range. On most things that doesn't seem to be a problem but on the rather sad but new and cheap TV that I foolishly use as an external monitor I can get it very easily to loose sync on every fade to black and many dissolves. Putting a track of black at a legal level underneath my entire project fixes the problem. BC filter at Extremely Conservative will too but that takes ages to render.