Final Cut Issues - "skipping/jumping frames"

[Samuel M. Hain]

Hi guys, I've been dropping braincells left and right trying to figure out what could be causing this problem, maybe someone reading this has a solution or a suggestion;

In a nutshell, once we've compiled and burned our DVD, we end up with a "skipping/jumping" frame here and there. Noticeable.

This doesn't seem to affect the audio at all, but simply watching it, seeing a frame "jump" and/or "skip" (within the same shot, that is) is really beginning to annoy me, as I'm sure you can imagine.

We can ever know if and when or where this issue will occur until we actually watch the DVD, so you can imagine my frustration of waiting 16 hours for my rendered DVD, sitting down and then seeing this problem again and again.

The jumping and/or skipping frames are never the same. Either they're at the beginning of the film one time, or in the middle another time, near the ned another time.

I was expecting another DVD this afternoon from the guy doing the actual rendering/burning, but got an email from him a little while ago informing me of "yet another delay blah blah".

Each time he has an issue, I have to wait days (nearly a week, that is) for another rendered DVD.

My "guess" (I'm no editor, bare in mind I'm just the director) so my technical knowledge of this is nearly moot, however, to me, this feels like it could be simple problem being overlooked on his end, like, perhaps;

1) maybe he's doing other things on his computer whilst rendering?

2) maybe his computer just can't handle the processes? (Macbook, Final Cut Pro 6)

3) maybe tiny nano-bugs are shitting on the files and laughing at me?

ANY tips, advice would be GREATLY appreciated.

SH

 

[oakstreetphotovideo]

If the original video plays perfectly, the first place I'd look would be the MPEG-2 compression program (the one that "renders" the video for DVD). Is he using Compressor? What bit-rate is being used? Is it variable bit rate (two pass) or constant bit rate compression?

If he is not using Compressor, I'd recommend that he use compressor. If he is using compressor, try lowering the bit rate.

The next thing I'd look at is the media. Some DVD media just sucks. I purchased "pro" media once, in bulk, from a certain manufacturer that I won't name, just yet, and found that about 1 out of 5 disks wouldn't verify and 1 out of 3 of those that did were returned to me as unplayable or fraught with errors. I will not burn on anything except Verbatim Datalife Plus disks, now. I have never had a Verbatim Datalife Plus disk returned to me, and I've sent out well over 200 disks. The media does matter; especially recordable media in set-top DVD players.

Doug

 

[Samuel M. Hain]

Hi there oakstreetphotovieo,

Much thanks for the info.

What I can tell you at this point is;

Yes, the original video and audio play fine. As for compression, I'm honestly not sure. What I'll do is give him a call shortly and get all this info and post it back here for you to see. I can also tell you at this point that the media being used to record the film onto DVd is "FujiFilm DVD+R" (120 min).

As mentioned tohugh, I'll speak to him shortly and get all this info. Much appreciated!

SH

 

[oakstreetphotovideo]

If your authoring guy is using DVD Studio Pro, tell him to select "hard disk image" as the target when doing the "compile and burn" step. That will give you 2 advantages. 1) You can mount the image and play it directly on the computer (no disk) to see if it plays correctly, before burning it. 2) You can use disk utility to burn it repeatedly at different speeds and to different media, until you find something that works. By creating a hard drive image of your DVD and testing that. You will know, without wasting any media, if the problem is in the encoding, or with the media.

The next thing I'd do, once you have an image that you know is good, would be to burn a DVD with a slower burn speed (try the slowest speed, to see if it makes any difference). Burning at a slower speed often results in a more reliable burn. If that doesn't work, try DVD-R media. At one time, DVD+R was prohibited for DVD authoring, due to limited support in players.

 

[Samuel M. Hain]

DVD Studio Pro is the program within Final Cut 6 yes? (sorry, as mentioned, I'm not the tech-minded one here). If so, he is indeed using that program to render n' burn, as far as I know.

I was also inclined to assume he was burning it too fast as well. I'll have to check with him on those elements and see, however.

Thanks again!

SH

 

[knightly]

the skipping and jumping frames...is it possible this is a pulldown issue? How was it shot (framerate, camera, etc)...how was it captured? Is the skipping a regular (happens predictably in the video - every x frames it skips). Can you pull some of the video off the DVD and post a clip for us to evaluate...otherwise, we're all just taking shots in the dark that we know what you're talking about.

 

[oakstreetphotovideo]

I'd lean away from a pull-down issue because it sounds like the problem is highly intermittent.

The jumping and/or skipping frames are never the same. Either they're at the beginning of the film one time, or in the middle another time, near the ned another time.

My money is on bad media or marginal burn quality (burning too fast). I've used both Compressor and DVDSP for encoding and I've not seen this, and the speed of the computer doing the encoding would not affect encoding quality, just how long it takes to complete.

Doug

 

[spinner]

Hi, Oak, Samuel and knightly

Just out of curiosity: might not the problem be how the project is being exported? I didn't have skipping or jumping frames, but I had issues with my final project as well. One of the first things knightly suggested was to change the way it was being exported and that improved what the project looked like.

I don't know if that will help, but its something else to look at. And since I have a Mac, I make my DVDs through iDVD and it seems to work for me.

-- spinner

 

[oakstreetphotovideo]

Just out of curiosity: might not the problem be how the project is being exported? I didn't have skipping or jumping frames, but I had issues with my final project as well. One of the first things knightly suggested was to change the way it was being exported and that improved what the project looked like.

Yes, how the project is exported will affect quality. However, it would affect the quality of the entire movie, it would not create a glitch here and there. Stutter from frame rate translation would occur every few frames, or several times a second. In this case, I don't believe that the problem is export options or conversion factors. It's also unlikely that the encoding was done incorrectly, unless the encoder is just a shoddy piece of software. Both Compressor and DVDSP have high quality encoders.

I would never, and have never used a DVD+R disk for a DVD master. I believe it is ill advised. Also, and everyone should take not of this; the maximum burn speed for any disk is right at the edge of the media's capabilities and you'll always have a more reliable disk if you burn at a lower speed. I never burn DVDs for distribution at their rated speed. I burn my 8X disks at 4X and I used to burn my 4X disks at 2X. It takes a little longer, but in the end you'll save more than you'll lose.

Since I have a business authoring DVDs and I author at least 50 DVDs a year, this is an area I know really well. It's also an area where I have an edge on my competition, because my competition keeps giving customers disks that won't play right. I have learned how not to do that, and it makes me look much more professional. Of course, you are right in that everything else must also be done correctly to have the highest possible quality disk.

It's Saturday night and I'm still working. I hope I don't sound cranky! Please accept my apologies if I do.

Doug

 

[Samuel M. Hain]

Hi Guys,

Gotta give a HUGE thanks for those responses. (I asked the same questions in a local forum and basically got laughed at and told to go to "film school).

Right, so here's what I've got;

The medium being used to burn the DVD is Fujifilm DVD+R, and from what you've both mentioned, this is a virtual no-no, so I've passed along that bit of advice to the guy doing the compression and burning. Whether or not he'll change the medium, remains to be seen, and I wont know this until Monday when he brings the DVD to me.

Secondly, I had a chat with my editor who, is experienced and skilled, (she didn't do the color correction however, the guy burning the DVD did), and she also mentioned what you guys mentioned about the MPEG-2 compression as well as the bitrate adjustment.

The guy burning the DVD is in fact, using "compressor". He mentioned he DID play with the bitrate several times. (Why several times, I do not know!)

Now, for the final and hopefully the primary issue, the speed of the burning process; I didn't get a response to this when I asked in an email, and I can't reach him (he's out of town until Sunday night) but I'm pretty damned sure he's burning the DVD too fast.

I'm well aware that burning anything CAN in fact cause such intermittant issues, as I've burned many a DVD and CD in the past. The guy doing the burning right now is anxious to get the thing to me and "approved", and he's quite busy these days with other projects, so I'm inclined to believe he just isn't taking is time with this project, so I'm left to assume that when he does in fact burn the disc, he's rushing it at a higher speed.

My fear is that we've already missed 2 film festival deadlines, of which we had been "expected" to make, and because of these misses, my executive producer is getting very frustrated as yet another deadline is near approaching and he has YET to view the final product.

Again, I thank you guys for your responses.

By the way, "oakstreetphotovideo", do you happen to have website? *** SCRATCH THAT question, I just found it.***

SH

 

[oakstreetphotovideo]

By the way, "oakstreetphotovideo", do you happen to have website? *** SCRATCH THAT question, I just found it.***

I just wish I had time to keep my web-sites up to date! I'm kind of a one-man army over here. I've got a couple of people I use when I need crew or talent, but I do everything else myself ... I'm pretty sure my life expectancy is that of a house fly.

 

[Samuel M. Hain]

aha! You and me both good sir!

I'm one of those people who believe, "if you want something done right, do it yourself!"


Ok, so it takes its toll on us both mentally and physically, but at least the job gets done, and done well.


Don't houseflies live for 48 hours?

There's a scary thought ya?

SH

 

[Samuel M. Hain]

the skipping and jumping frames...is it possible this is a pulldown issue? How was it shot (framerate, camera, etc)...how was it captured? Is the skipping a regular (happens predictably in the video - every x frames it skips). Can you pull some of the video off the DVD and post a clip for us to evaluate...otherwise, we're all just taking shots in the dark that we know what you're talking about.

Hi Knightly, sorry...I hadn't seen this reply.

Actually it's not a pulldown issue. The rest of the film is fine, both video and audio are synched and running fine. Each time there's a render and burn however, the skipping or jumping frames are not the same ones as the previous render.

I'll try to rip a scene from the DVd version I have here and post it however. It's an ugly little blip that just eats at me.

SH

 

[Samuel M. Hain]

Hi Guys,

Well, the verdict is in;

I grabbed some DVD-Rs, had the guy over to burn the film and within 15 minutes I was watching the film.

Everything looked great and sounded great right up until about half way in. a Single, tiny "lag+skip" in one of my steadicam shots. (The entire scene is 4.5 minutes, one shot. There are no cuts in the scene at all).

We paused the DVD player and opened up the computer to bring up the same scene in the actual render so see if that "lag+skip" was there, or in the burn.

Sure enough, it was in the render, which leads me to believe the problem is now not the DVD medium, but in the MPEG-2 compression.

We decided to contact the editor herself and ask her to take care of the rendering, since her computer is more powerful than that of the one we were using yesterday. I've a feeling, the computer we were using just cannot handle the large file size when compressing. (he's using Compressor, in case I hadn
to mentioned that).

Other than that one little glitch, the film looked fantastic.

SH

 

[oakstreetphotovideo]

We decided to contact the editor herself and ask her to take care of the rendering, since her computer is more powerful than that of the one we were using yesterday. I've a feeling, the computer we were using just cannot handle the large file size when compressing. (he's using Compressor, in case I hadn to mentioned that).

At the risk of sound argumentative, there is no "real time" requirement for compression. It is simply a computer program that runs as long as it has to, to complete the job. It is possible that the bit-rates selected were not sufficient, or excessive, such that the compression algorithm failed to product correct results, or the results were simply out of spec due to an bug in compressor. As a software developer, I'm inclined to believe that, given the same inputs, and exactly the same software version, you will get the same results from a faster machine. It is, possible, though, with all of the optimizations for processor pipelines that are specific to a particular CPU, a G5 or Intel may succeed where a G4 fails (or vice versa).

You may also be doing something I don't do. I generally encode my DVDs in chapters and assemble the chapters in a single track in DVDSP. That allows me to set compression parameters by chapter, and more importantly, I can quickly re-encode a chapter, if I find a problem in the 11th hour. I do not need to re-encode the entire program. I do often have long running scenes with no cuts; up to 15 minutes is typical. I don't think the compressor cares about cuts/scene changes, it sees the video as a stream of frames, from beginning to end.
Another thing I like to do, if I have the disk space, is to export the entire program out of FCP to a Quicktime file (very large file), and feed that file to Compressor, so I can free up FCP to continue editing. This also allows me to play through the QT file to be sure FCP hasn't introduced any glitches. I hate to say it because Apple isn't going to invite me to their parties anymore, but FCP 6 is buggy as hell; even more so than FCP 5. :O

Doug

 

[Samuel M. Hain]

Hi Doug,

It's funny, the very last thing you mention is the exporting to a Quicktime .mov file and then loading that file into Compressor, then burning.

I'm n ot sure (yet) if he's rendering in a Quicktime format first, I've been told by some other editors that he most likely is not doing that.

Again, I cannot reach him to ask him this rather simple question, but when I do, I'll post the response here.

Thanks again!

SH

 

[Samuel M. Hain]

Doug,

I just spoke with my editor, who (is not rendering this, again, my DoP is), and she assured me that my DoP is NOT rendering a .mov file first.

The film runs for 96 minutes, has massive amounts of color correction.

Now, gradually, and after reading more and more about these technical aspects, I'm happier knowing that when people talk-tech, I can now understand a bit more of the issues and their possible corrections and neccessary procedures.

The film is being rendered, as we speak (was started last night at roughly midnight), and I have a feeling he's rendering it, yet again, as he's been rendering all along. Another 16 hours of rendering wasted.

I'm at my witts' end with this now, as I'd mentioned, my deadline to get this into my exec producer's hands has passed by about 4 weeks now.

Out of curiosity, how large will the rendered "quicktime file" be for a 96 minute film?

SH

 

[spinner]

I'm n ot sure (yet) if he's rendering in a Quicktime format first, I've been told by some other editors that he most likely is not doing that.

SH

...that is why I was asking how he was exporting your project. I can tell you what I know about Final Cut:

When you export, there is: QuickTime Movie, Using Compressor, and QuickTime Conversion. I use QuickTime Conversion and you can believe that if your project is 96 minutes long, it will take a long time to render. My projects took forever (4 hours) and it was only 23 minutes long. And once rendered, it was 2.8GB. Exporting it this way I don't have many problems, though I did initially as any newbie would.

Usually, I start it exporting, then I go to bed so I am assuming that it took up the 4 hours it said it would need....

-- spinner

 

[oakstreetphotovideo]

The only reason to export to Quicktime, rather than using Compressor directly, is to determine the point of failure. By useing export to Quicktime (not export using Quicktime conversion), the final movie will be the same size as your render files in FCP. Essentially, it renders with the sequence settings, so if your sequence is DV50, you'll need about 5MB/second and if it's DV25, you'll need about 3.5MB/second. That's 28GB and 20GB, respectively. If you're using a less compressed or larger format in your sequence, then it could be a lot larger. That's why you would generally export directly to Compressor. Also, exporting directly to Compressor can yield some quality advantages over using an intermediary.

However, to reiterate my original point, if you don't know where the error is being introduced, you've got to break up your pipeline and check the output of each step for errors. Otherwise, you'll spend the rest of your life trying things and never figure out which tool and/or which setting is creating a problem. I've had FCP do some evil things to me; even on 30 seconds spots. Sometimes I have to trash all of my render files and quit out of FCP completely, to get it to export my most recent changes in Motion, or what have you.

It might make you happy to know that exporting to Quicktime is much faster than doing on-the-fly compression. If you've got 40GB free on an external drive, or something, I'd give that a shot and then watch the entire QT file for errors before spending 16 hours encoding for DVD.

Doug

 

[Samuel M. Hain]

Hey guys,

Here's what's going down today, in about 30 mins;

I've got my DoP (dude doing the rendering) coming over with his laptop (yep, the one used for all previous crap renders), but after spekaing to an editor here and figuring out that the way he was rendering prior, was completely wrong (thanks to you guys as well, by the way), he'll be collecting the film files from the external drives, and loading them into his lappy, then rendering and then compressing.

My final deadline to have this complete and into New York is today/tonight. I'm hoping to hell it works flawlessly today, as I'm about to have my exec drop this production.

You can imagine my sheer frustration at this point. I don't know what sleep IS anymore, and after reading the forums over at apple.com, I'm having nightmares whilst awake!

I'll let you know how things go.

Thanks guys,

SH