[tonbo0422]

I'm using a G4 350 with an IBM 60GB drive. I have 900 MB of real RAM assigned to iMovie. I'm using a Dazzle Hollywood DV bridge and exporting to an older Sony hi-fi VCR, which is taping at SP speed.

My problem is this: when I export the movie using iMovie's "export to camera" option, everything seems to work fine, but when I play it back on the tape on TV I see that in parts the audio seems to stutter markedly (and the video looks a bit jerky.)

I've exported the same movie three or four times and the stutter seems to occur in different places each time. Since it's a "music" video, the stutter is very noticeable. Note that the pitch of the music doesn't change, it just stutters, like it's laboring or something.

This doesn't happen when I export to QT 5.0 and play it back on my computer.

I'm using a fair amount of "reversed clips" in the movie--could this be the problem?

Try the followings:

Virtual Memory - ON.

I movie memory Min- 50000 K Prefered - 75.000

AppleTalk - Inactive

EDIT > Preferences > Show Thumbnails in time line (Unchack !!)
No Thumbnails will make the project much lighter.

It should work fine now.

Danny.

[tonbo0422]

Danny,

First, I have more than a Gigabyte of RAM so am not allowed to turn on Virtual memory by the control panel.

Second, I have 900 megabytes--not 90 megabytes--assigned to iMovie. Is your particular combination of suggested and min memory something that is an iMovie trick, meaning that combo will make it work better? I can't see how, but one never knows.

AppleTalk--I'll try it off (it's definitely on!) Maybe while I'm at it I'll turn off file sharing.

I'll try the unchecking thumbnails! I'll give a full report.

Thanks for the help!

--Nick

[Randycat2001]

Do you have frequent cuts, edits, and effects thoughout your iMovie or is it in one contiguous DV file? Maybe your computer is having problems doing all those video acrobatics in real time as it exports to camera? Try exporting your finished content to DV on your HD and then exporting that file to your camera. Maybe a disk defrag couldn't hurt either? Since iMovie is spooling the video signal from a DV file, it demands significant bandwidth (2-3 MB/s continuous with absolutely no skips) from your HD (vs. spooling from a compressed file format). Though I imagine your modern 60 GB HD should be quite sufficient to handle that under optimal conditions, moderate fragmentation of a particularly large file can slow that performance down pretty drastically.

Also, have you tried viewing the "About this Computer" window while you are exporting from iMovie? Is it showing a 900 MB long bar with only a tiny amount actually in use (the shaded portion)? If so, then that probably means that the bulk of that 900 MB allocation is probably just going to waste, as iMovie isn't even bothering to use it. In that case, you should probably default to a smaller allocation. I think I have mine set to about 30 MB, and even that leaves plenty of unused memory while its running.

[tonbo0422]

Absolutely brilliant reasoning. The file indeed, has MANY edits and transitions etc. Fragmentation could indeed be a factor too. I think just the fact that my processor is 350 Mz is living on the edge here as it is, so you're right, I should give the file all the help it can get vis-a-vis fragmentation etc.

I thought about creating a Quicktime version and then exporting that, but I want as few degradations as possible. I'm not an expert on how many pixels wide the screen should be or what Mz the sound should be, so I rely on iMovie's quick-and-dirty categories, which are a real boon to mathematically-challenged oafs like myself.

(Also, I'm of the older analog tape school who still believes that the more times you mix it down the worse the hiss becomes.)

You're also right about the memory allocation being overkill. Still, the idea that the whole movie could live in RAM is seductive, but I guess if the processor doesn't cooperate . . . also, does Quicktime have an option to export out to "camera.?"

By the way, I do have Final Cut Pro, so I'm wondering if it might handle anything differently . . . its learning curve is definitely a hindrance.

Thanks for the great suggestions. I'll try them and see how it comes out.

Cheers--Nick

[scottnichol]

Originally posted by tonbo0422:
<STRONG>Absolutely brilliant reasoning. The file indeed, has MANY edits and transitions etc. Fragmentation could indeed be a factor too. I think just the fact that my processor is 350 Mz is living on the edge here as it is, so you're right, I should give the file all the help it can get vis-a-vis fragmentation etc.
</STRONG>

i don't think defragmentation will help that much. its probably more beneficial to work with a stripped down system (definitely disable apple talk, internet connections, AOL instant messanger...) these things suck up system resources and take priority over the DV play through to your external DV devices.

<STRONG>
I thought about creating a Quicktime version and then exporting that, but I want as few degradations as possible. I'm not an expert on how many pixels wide the screen should be or what Mz the sound should be, so I rely on iMovie's quick-and-dirty categories, which are a real boon to mathematically-challenged oafs like myself.

(Also, I'm of the older analog tape school who still believes that the more times you mix it down the worse the hiss becomes.)
</STRONG>

this is partially true in this case. if you export it as Quicktime, unless you export as NTSC DV with your audio at 48Khz, you will be re-compressing, then whatever you use to get it out over the fire wire will have to re-encode it as DV again and you will see the re-compressions.

the key is to make sure all your transitions and fades are fully rendered and play smoothly from start to finish on the system to begin with. i thought iMovie had a way to turn off background rendering of effects? if this is on, you may have to manually render everything.

<STRONG>
You're also right about the memory allocation being overkill. Still, the idea that the whole movie could live in RAM is seductive, but I guess if the processor doesn't cooperate . . . also, does Quicktime have an option to export out to "camera.?"
</STRONG>

the whole movie can't live in ram - DV is 216MB per minute of video. how many minutes is your film?

you could export it from iMovie (as a pure DV stream and you there won't be any visual loss from compression) and bring it into FCP. then you can do a print to tape and see how it looks. you can hook a TV up to the VCR and actually preview everything before you press record.

the skips and stutters you are seeing are dropped frames. in other words your mac is trying to decode frame 1275, but the time code says its supposed to be on frame 1290, so it just forgets about trying to do those frames in between and jumps to 1290. so minimize your extensions (try the "MacOS 9 All" extension set in the extension manager control panel) and try again. giving it more ram won't help.

scott

[ 08-01-2001: Message edited by: scottnichol ]

[Randycat2001]

Originally posted by tonbo0422:
<STRONG>I thought about creating a Quicktime version and then exporting that, but I want as few degradations as possible.</STRONG>

You should be able to export DV format from iMovie (check your options panel while in the export window; DV should be one of the choices along with the various other encoding formats). That way your movie will be one big clip of original digital footage instead of a compilation of clips, edits, and transition effects. Then defrag that DV file using Norton or other. That should ensure that the HD will read off the file in one long, contiguous sweep when you export to camera. Hope that helps.

[tonbo0422]

The DV option sounds like what I want, if it's one continous clip. I guess the correlation to analog recording tape, say 8-channel audio, would be mixing it down to two tracks, then outputting it instead of outputting the eight tracks through two channels.

[Randycat2001]

That's pretty much it, except in this case the DV to DV transfer is virtually lossless as a bonus. The only drawback is the massive amounts of HD space (as long as you have it to spare) that will be required since you will have 2 copies of your project in uncompressed format in the end.

Originally posted by tonbo0422:
<STRONG>The DV option sounds like what I want, if it's one continous clip. I guess the correlation to analog recording tape, say 8-channel audio, would be mixing it down to two tracks, then outputting it instead of outputting the eight tracks through two channels.</STRONG>

Well ??

After all the thoretical stuff from the senior members, What
happans to your movie ? Did you export it succesfully ?

Danny.

[tonbo0422]

Heh . . . after all that great help I couldn't justify trying it out on my old Sony, so I went out this aft. and bought a whole new deck.

I'll burn it tonight and report back tomorrow.

[tonbo0422]

Well, the whole "DV" thread dies a quick death. There are exactly two options in the export menu: "Camera" (ie. to the video deck I'm using) or Quicktime.

I guess it has to be Quicktime.

[Randycat2001]

Are you still trying to figure out how to export your project to DV format? If I understand correctly, you won't see the DV option in the outermost menu. You have to choose "to Quicktime" (working from my memory here), and then a new window pops up where you can select DV output. Is this what you are pondering? I'll look it up when I get home, to make sure... Trust me, you can export a DV file, just like you would export to any other codec.

[tonbo0422]

rcat,

I tried holding down the option key while selecting "export" (I know, goofy, but you never know what holding down the option key will turn up!) but still only got the "Quicktime" selection as my alternative to camera.

Obviously, this means "export to DV"--this time meaning "Quicktime"--but then even if I get it to Quicktime, Quicktime's _own_ export options seem to limit it to "file", ie. to the desktop, not my VCR.

Still, when I exported to the new VCR, there seemed to be much less skipping. (Then, another iMovie problem presented itself: if you render your files for export but don't save your file, iMovie won't recognize your rendered files when you quit it and reopen the file. This is scary, maybe worthy of another thread.)

I also encountered another problem while investigating all this.

Thinking that perhaps Final Cut Pro would import the whole iMovie project lock-stock-and-barrel, I tried to import it into FCP. Needless to say, it wouldn't import. Obviously it has to be in a format FCP understands, and that is not iMovie.

Sorry for being an AV newbie--these issues would not be issues to a pro. Obviously I'm not doing my homework.

--Nick

[Randycat2001]

I'm not sure we're on the same page, yet. Are you trying to export your project to a DV file, to your VCR, or to a DV file and then later into your VCR?

Sorry, I didn't get back to you like I said I would yesterday. Here is what I found when I fired up the ole iMovie2 app. First you select "Export Movie..." from the File Menu bar. Then on the Export button, select"to Quicktime". Now here is the tricky part- right below this you should find the Formats button, where you should select "Expert..." This will open yet another window. Under the Image settings of the window, click the Settings button to reveal yet another window (could they have buried this any deeper?!). Here you can choose the specific video compression you want for this project when you export it. Along with those choices you can select straight NTSC-DV. That is what I think you are looking for? Then work your way out of all those menu windows and export your project.

When all is done, you should have one giant DV file. Then you can import this file back into iMovie under a completely different project. Then try exporting to camera like you were doing before. Seems like a lot of work just to get some skip free VCR footage (if indeed, this even fixes your problem), so maybe I'm going about this in a really awkward manner. I hope it works out for you, and if it still skips, I am truly sorry for leading you on wild goose chase. Let me know if you need further clarification on the directions I gave above.

[tonbo0422]

RCat,

No, those were very explicit directions. I had been hoping to avoid the "Expert" options, though, since I don't know which ones will get me the best output. (Too bad there isn't an option which says "highest quality--uncompressed" for jargonphobes like me. I wouldn't know a Codec if it bit me.)

All I originally wanted to do is make a movie in iMovie, then export it to the VCR with as clean a copy as possible.

It takes so much time to experiment with these 5 gig files that it's slow going, but already, with all the advice given, things seem to be dubbing fine--none of the stutter that I saw in the beginning. Could have just been the Appletalk!

[Randycat2001]

Originally posted by tonbo0422:
<STRONG>Too bad there isn't an option which says "highest quality--uncompressed</STRONG>

Actually, there is such a setting, though I have never tried it personally. Instead of choosing "Expert...", try the "Full quality, large" setting.

[tonbo0422]

Here's the update:

1. Tried redoing the dub. Removed all extensions except those that were absolutely necessary. Restarted to clear RAM. Rendered the movie, then sent to video. Result: quite noticeable skips and stutters.

2. Output the movie from iMovie to Quicktime, highest quality. Tried to reimport into iMovie, but that's not an option. Exported the QT file as a DV stream, which ended up being 9 Mb less than the QT file.

Imported THAT into iMovie, then exported to the VCR. Result, much less skipping and stutters, but still present--again, not in the same places as before.

Now: optimising hard drive. Will try 2) again, this time not using the beginning of the VHS tape (sometimes the first couple of minutes on VHS tapes are funky.)

I'll let you know. Hopefully at the end of this I can post the result on my site so you can see what I've been talking about , though you won't have to watch the VHS version