To Filmy and all others with Black Frame problem: Think I figured it out!

TheHappyFriar wrote on 10/10/2003, 7:45 AM
I did a test based on a post I made in Filmy's thread (http://www.mediasoftware.sonypictures.com/forums/ShowMessage.asp?MessageID=220257&Page=1).

Here's what I did: I took a clip I captured and plopped it on the timeline. I checked it for black frames. None. I even checked the start and end of the clip.

The clip was alone on the timeline.

I rendered the first and last 3 seconds of the clip to a new track (New Track 1 & 2). Checked those for black frames. Track 1 (the first 3 seconds) didn't have any. black frames at the start or end. Track 2 (the last 3 seconds) had a black frame AT THE END.

I zoomed in on the timeline. A black frame thumbnail showed up. It was black in the preview window too. I changed my preview quality up to Best (Auto) from Preview (Auto). Still there. Hmmmm... I changed to Best (Full). Black frame DISAPEARS and it replaced be an interlaced picture. The odd fields are black, the even are my picture.

Why?

Well, the preview NTSC only shows the even fields unless you have the preview setup to Full.

When you render it will take 1/2 of the frame (odd fields) from the current frame, and the other 1/2 of the frame (even fields) from the NEXT frame.

If you next frame is black, you get a black frame (or an interlacedblack/picture frame).

Solution? Have video AFTER your pre-render's and new track renders.

Now, Filmy, I belive you said that Premiere didn't do this (well, not directly, but i belive you hinted this). Just so everyone knows, I DUPLICATED THIS IN PREMIERE!! It's NOT a Vegas "glicth," it's the way NLE's handle interlaced footage.

The reason I've never had this happen before is because when I do my pre-renders (new tracks), I render finished parts: ie parts with footage after them.

Go ahead and try it yourself: take a captured clip. Render the first 3 seconds to a new track, the last 3 seconds to a new track. Zoom in and view. Delete your new tracks, leaving your origional clips. Plop another clip up against the end of the 1st. Render to a new track a 3 second clip of where they meet (1.5s before and 1.5s after the join). Find the joint and see no black frame.

Duplicate this in Premiere, FCP, Avid Free DV, whatever. It will happen in almost every one of those i bet.

:)

Comments

Spot|DSE wrote on 10/10/2003, 8:39 AM
As suggested in the other thread, this is the half-frame display. This is NOT a Vegas phenomenon, it's an NLE issue that all NLE's have. Adam Wilt did a wonderful article on this a couple years ago. This is a small part of the reason for quantizing frames as well.
You don't need video after the next frame, empty media will do. Split your display and do this same experiment in Vegas with media rendered from any source that was interlaced. You'll see it.
TomG wrote on 10/10/2003, 9:51 AM
HF ->Solution? Have video AFTER your pre-render's and new track renders

OK, what exactly does this mean? Where do I put the video (or empty media) in order to eliminate the black frame? Again I see this when I have a cut on the rendered video but I don't understand the solution? Excuse my ignorance....

TomG
filmy wrote on 10/10/2003, 10:40 AM
Well good work but this is not my problem.

What you did:

1> Took a clip and placed it alone on the timeline and found no black frames.
2> Rendered the first and last 3 seconds of that clip.
3> Found black frames in the render

Now what I was mostly talking about:

1> Take a series of clips and drag them onto the timeline. The clips are numbered part1.avi, part2.avi, part3.avi. etc. Make sure the auto transitions function is turned off. VV automaticly places these clips on the timeline in order with a "cuts only" method. The clips are fine, no black frames. That was never the issue what the issue is -

2> Instead of "cuts only", where these clips are butted up to one another, VV will leave spaces in between and when you render these spaces become black frames. If you manually move these clips so they actually do butt up to each other these spaces obviously go away - thusly no rendered black frames. So the issue is not so much the render for me but the way clips are handled on the timeline.

That is one part - sort of a root of black frames. These spaces in between edits. Your "solution" is this: "Plop another clip up against the end of the 1st. Render to a new track a 3 second clip of where they meet (1.5s before and 1.5s after the join). Find the joint and see no black frame." And this is exaclty what I have been saying and this is exactly the issue - VV oft times places small spaces in between the edits and to fix this you must go into the timeline and look at each edit to make sure these spaces are not there. On a feature film - an action film - to go through every single edit is not something that should have to be done. (At least not checking for spaces the NLE has placed there)

When you simply drop these tracks onto the timeline you "expect" them to be in order with no spaces in between edits. Also when you "insert" you expect there to be no spaces in between edits, but there can be because of various reasons such as ripple edit pushing edits down the line up instead of at the edit. As I said in the other thread - 1,2,3,4 should be the correct order but you can get 1,2,3,2,4 or 1,2,4,3,4 or 1,2,3, blank space, 4 during an insert. In the "empty space" example what I, and others, have seen is: 1, blank space, 2, blank space, 3, blank space, 4. But, again, it is not as simple to reproduce because I have gotten 1,2, blank space, 3,4 and I have gotten 1, blank space, 2,3, blank space, 4.

So I am trying to explain this as best I can and and easy i can - we have a few issues really but they all are somewhat connected.
TheHappyFriar wrote on 10/10/2003, 11:04 AM
I tried dropping 7 clips on the timeline on at once. I did this several times. I couldn't get the black frames to appear. I tried different settings for the auto transitions with the same results.

Now, I DID had black frames at the start of a couple of my clips. I know that it wasn't black when I started recording, so I am assuming that the capture program put those in.

I assume you checked your origional footage/clip, but just in case.... did you? :)


oh, i forgot to say that i tried the same thing in premiere, and played the clips in media player. I got the same results in Premiere and media player showed a black frame at the start of the same clips as Vegas and Premiere.
SonyEPM wrote on 10/10/2003, 12:00 PM
"Take a series of clips and drag them onto the timeline. The clips are numbered part1.avi, part2.avi, part3.avi. etc. "

You probably said this at one point but I need a refresh:

1) The original source material was:

2) The clips were rendered in Vegas (right?)

3) The exact render settings used to create these clips:

4) The Vegas project settings at the time of render:

5) The Vegas proejct settings used for editing:
filmy wrote on 10/10/2003, 12:08 PM
>>>You probably said this at one point but I need a refresh:<<<

Yes i did, From September 1 - Here is the thread in question, - http://mediasoftware.sonypictures.com/forums/ShowMessage.asp?Forum=4&MessageID=210602

That was the first time I ever had this issue however if you re-read the entire thread I was not the first. The problem was the same as this project, the setting and proejct were different. As far as *this* project -

>>>1) The original source material was:

Source materal was sent to me already captured. I believe they used DV300 (?) board for capture and they captured in Premiere 6. All material is on a seperate system from my edit system. All material is NTSC, 30P

>>>2) The clips were rendered in Vegas (right?)

No rendering yet on this project yet - only a PTT and the small pre-renders that happen for a PTT. And again - this is not a render issue for me (yet) this is a timeline issue. Empty spaces that VV adds to the timeline in between edits - I call them "black frames" because when you render an empty timeline what do you goet? Black frames.

>>>3) The exact render settings used to create these clips:

See above.

>>>4) The Vegas project settings at the time of render:

See above. No rendering.

>>>5) The Vegas proejct settings used for editing:

Default NTSC dv setting with one change - fields set to "none" as source footage is progressive.

That is it. I am editing via the timeline. Unlike the other project I am not dropping lots of media that is pre-numberd onto the timeline but I give that as an simple example of what I did and got the same result - empty spaces in between edits. As for this project what I am doing is either 1> Opening up another instance of VV and selecting all/grouping all and than "copy" and go to the output project and "pasting" that scene onto the timeline. (The first PTT output was a new timeline - same settings NTSC DV default with fields changed to "none" and all was pasted in order. No inserting done at all. During PTT all these "black frames" flashed by. When I went back into the time line I found , as I have said, "empty spaces" in between many of the scenes and in some cases in the actual scenes, in between some of the edits that had not been touched at all. They were not in the timeline of that scene but they were added when I dropped that scene onto the new output timeline. )

and 2> The "ripple" issue became more apparent because the other night I went into that output timeline and added slugs. The default 5 second (or the 00:00:04:29) time was used and sometimes it worked perfect and others it added this "empty space" into the timeline. I also found at least one edit that had an extra frame of audio added - not an extra rendered frame but a VV "extended" extra frame. (Same as described by someone over in the other thread I listed above) So this was a frame of empty video with an "extended" frame of audio. Only had this happen one time here however.
filmy wrote on 10/10/2003, 12:12 PM
>>>I assume you checked your origional footage/clip, but just in case.... did you? :)<<<

I thought I had said this arleady - all orginal media is fine. I can frame by frame through it and no black frames.
rmack350 wrote on 10/10/2003, 1:50 PM
Hi Filmy,

I have no answers for you but I have some questions. Mainly for my own edification.

If the source is 30P, and the project settings are 30p, then the recorder must also be 30p? Is that why there's so little rendering-that the format stays the same from start to finish?

Rob Mack
FadeToBlack wrote on 10/10/2003, 2:14 PM
rmack350 wrote on 10/10/2003, 4:06 PM
At first glance it seems like this happens when a clip with an odd number of frames is butted up to a clip of even numbered frames.

Additionally, It seems like my cursor position makes a difference. If I ctrl+alt+arrow to the end of an event and then drop a clip there I might get a black frame at the other end.

If I had ctrl+alt+arrow twice (moving to the beginning of the NEXT clip) I don't see the black frame. Does this make sense? Maybe I'm not looking carefully enough-I'm also trying to work.

Rob mack
rmack350 wrote on 10/10/2003, 4:17 PM
Okay, I think I'm seeing a small light in the dark...

If you move your cursor to the end of a clip you shouldn't be seeing the clip in the preview window. If you DO see it then you are one frame away from the end of the clip.

If you drop a clip and try to butt it up to the previous clip while your cursor is one frame off then MAYBE the dropped clip will snap to the cursor instead of the end of the previous clip. This would probably be less likely the more you zoom in.

I'd always been told that if you want to insert media at the end of a clip then you need to go to the end and then go one frame furthur. If you can see the last frame of a clip in preview then you aren't at its end yet.

But why ripple would move things one frame too far is another matter...

Rob Mack
HPV wrote on 10/10/2003, 5:14 PM
I've reproduced the problem here. Four things together make it happen, and only then (from what I can tell). First you must have a big project going. Second you must add the multi selected media to a blank space in the timeline (created or at the end). Third you must have quantize to frames activated. Fourth you need to have source media that doesn't have equal length A/V streams.
I started with a stock DV project. Perfect match to the DV media I captured with VidCap. Automatic overlap turned off in prefs.
First I multi selection dragged 530 clips to the timeline with quantize to frames activated. All fine as I stepped thru every cut with CTRL/ALT/right arrow, even though many clips had one sample more video than audio. (More on that later)
Next I deleted some clips to create a blank space in the timeline and multi selected five clips from explorer and placed them into the black space. Bam, any clip that didn't have exact amount of samples for audio and video created a glitch at the cut to the next clip/event. Never a solid black frame, it is either two fields of video combined or one field of video and one of black. When both fields are video, one field is from the end of the first event, and the other is the last field from the second event. When it's a field of black with a field of video, the visual gap in the video track between events is about 1/2 of a 48K sample. If you turn off quantize to frames and do the same multi clip addition, all is fine. If you leave quantize to frames turned on and use media with equal A/V stream lengths, all is fine.
So, it does appear there's a bug. Don't know why it takes a bigger project to trigger it. The clips that produced the glitch have one sample less audio than video. My captures have this with both manual and DV scene detection. Being as all my clips have tails, I've never worried about this. And because I edit every clip I add to the timeline, I never use the multi selection option. Is this different length of A/V streams a result of consumer DV devices not using locked audio? Would DVCam with locked audio capture equal length streams? I bet this issue of different length A/V streams is responsible for every editing glich going in Vegas.
So filmy, it looks like I've found a workaround for you (if you MUST multi select clips to add to the timeline). First, turn off quantize to frames. Next, park your cursor on the timeline where you want the group of clips to start. Be sure to use adjust the position with ALT/arrow so your cursor falls on a true timeline frame break. Snap your multi selected clips to the cursor. All should be fine, but you might find that you have small gaps in your audio track. That's what caused your problem to begin with. Easy to check and see. Under the options menu, set your ruler format to samples. Now single click a clip in the explorer window and compare the number of samples for audio and video. Bet you'll see they are different. It's listed at the bottom of the explorer window.
I'm having a hard time understanding how you could be adding clips to your timeline that aren't trimmed in some way. Did you really capture everything at the exact length you need in the edit?
As for the ripple editing, all seems to be just fine here.

Craig H.
rmack350 wrote on 10/10/2003, 5:31 PM
I am using DVCam source and am seeing unequal streams of audio and video. I was also able to create a black frame using just a few clips.

But I should try this again with a long project after work.

Rob Mack
cacher wrote on 10/10/2003, 5:41 PM
HPV: In my case, I don't need such a large project for the symptoms to appear (maybe 30-40 clips is enough). If I adjust audio and video to the same length (as I have talked about in my other posts), I DO get blue triangles at the joint but if I do a PTT, the timeline shows that parts need to be prerendered (maybe just 1 or 2 frames). I have some jpgs that I will post soon.
rmack350 wrote on 10/10/2003, 6:10 PM
You know, when I have an audio track focused and I use ctrl+alt+arrow to move from event edge to event edge, I have to hit the combination twice to get past the audio cut. I only have to hit it once to get past the cut if I've selected the video track.

I THINK that if I'm on the audio track when I insert and ripple then that's more likely to create a blank. And it MAY only be when the audio is a litlle shorter than the video.

Really wish I wasn't at work as I'd like more time with this. This seems like an awful lot of conditions to make this happen but if you've got a routine going then you might routinely see the problem.

Rob Mack
FadeToBlack wrote on 10/10/2003, 7:23 PM
rmack350 wrote on 10/10/2003, 7:47 PM
Exactly.

I'm assuming that it's always the audio that's shorter. Does it make a difference if you have the video track focused when you drop the media on the timeline? Rather than the audio track? It seemed to for me but I haven't had enough time to dig in to it.

Could it be that, with quantize turned on and the audio track focused that Vegas is rounding down sometimes when it decides which frame to snap to? But when it ripples it rounds up or uses the video track to calculate from?

Rob Mack
craftech wrote on 10/11/2003, 12:42 AM
Careful guys,
This thread is sounding more and more "unintuitive". If all this is a problem just act "intuitively" and Vegas will either edit by itself, scan the Internet Movie Database for a new governor of the state of your choice, or envoke the second coming of Christ.

John
filmy wrote on 10/12/2003, 10:50 PM
RE: HPV -

Thanks for the possible solution. I will try it next time I am adding the cut scenes to the output.

>>>I'm having a hard time understanding how you could be adding clips to your timeline that aren't trimmed in some way. Did you really capture everything at the exact length you need in the edit?<<<

In the first case I had 30i > 24p conversions going on so in VV I loaded up the source material and than rendered out to 24p. What I ended up with was my 24p version so the material i was loading into my "ouput" project was my "answer print" so to speak. (After some talks with SoFo tech the end result was, for the 24p output, I just loaded it all into the VV Capture mod anyway so these space issues didn't matter)

In the current project I am creating new projects for each scene in the film. I am editing the scene and saving it. For the "workprint" output I again created a new project and because VV does not have nesting I open up 2 instances of VV. I take my edited scene and "select all" and "group all" and "copy" - I than go to my output project and "paste" that scene onto the timeline where it goes. I am "inserting" the entire scene into place. So that is how I am adding clips that are not trimmed - they are trimmed, just not in the output timeline.

RE: Audio issues -

To me this would make perfect sense, in either direction. If I dropped in media where extra video or extra audio existed there would be some sort of gap - either in the audio or in the video - at the edit point. Problem is what I am seeing is equal end points for both video and audio, plus the gap - now this is edit wise only as I explained above. In the other case, where I first had this show up, I was indeed dropping rendered video onto the timeline. There was one portion where the audio hadrendered fine but not video - for one cut. But that, I believe, was a framserver problem at the 30i end, not the 24p end...and not a timeline issue.

This may get a bit bouncey bounce because there are two threads now (current threads) that are talking about this matter. But as I see it something is causing these gaps to happen - and it is hard to be exact without seeing graphics. So here is my lame attempt at an ascii graphic

"normal" timeline view
 
| <<<Cursor
Video ======================================
Audio ======================================
| <<<Cursor

Zoom view on same timeline
| | <<<Cursor
Video --------------------------------------- -----------------------
--------------------------------------- -----------------------

Audio --------------------------------------- -----------------------
--------------------------------------- -----------------------
| | <<<Cursor

Ok - lame graphic right? I did do a snagit grab the other day to show what I mean...ohh it looks nice. Normal view look fine but if you zoom in you see the gap at the cursor. As observed if you place the cursor at the "end" of the cut you would see a black frame and if you place it "one frame back" you would see the same scene. In theory you want your cursor at the "black frame" mark to do your insert because if you placed it one frame back you would be, in theory, cutting off the last frame. (another lame ascii thing here - top one is "correct", bottom one is losing the last frame - video example only)

[][][][][][][]{BLACK}
| <<<<Insert point
[][][][][][][]|[][][][][][]

[][][][][][][]{BLACK}
| <<<<Insert point
[][][][][][]|[][][][][][][]

Now if VV inserts at the cursor - which it does - you get something like this if you do example 2 with "ripple" turned on.

[][][][][][][]{BLACK}
| <<<<Insert point
[][][][][][]|[][][][][][][]|[] <<< One frame from first shot now tagged on at the end of shot 2.


So, follow me here - "in theory" if you assume that blank space after shot 1 gets thought of as a "frame" it would make sense where these little gaps are coming from. VV is inserting at the cursor and moving that "blank space" to the end of the new shot. Or, like I said in another post, instead of inserting, say, 00:00:04:29 it is inserting the full 00:00:05:00. I am overthinking this way too much now - just trying to be logical here.

Now some would say "That is why VV will ask you 'after cursor' or 'after scene' or 'after the third monday of the fifth month, but only if sunrise was after 6 am'." But I don't want to think that much when I edit - I just want to select my in point and put the media in there and, if need be, have everything after it ripple on down the line. Editing is 98% feeling and 2% technical IMO and I really believe that VV is great for just feeling the edit - but all this other stuff is driving me nuts.