Why,why,why?

M

milleto

Well-known member
I'm so fustrated, you can't imagined.

I have a project on FCP6, captured 30p, no edits....this is fine so far..BUT I exported using compressor with the best quality for 90min, sound and movie...my timeline is only 20 min max. When I bring them to DSP the result is bad movie...jumps..jitters. Why, why?

I don't think I'm asking the programs too much but this seems to be impossible.

While a go I had the same problem..I worked around it by exporting as quicktime first, bring to DSP and compress there with only one pass and it worked. But for this project I wanted to be able to get better quality and easy workflow. SO, do you think it has to do with 2 passes? why is this a problem?

Again I had an issue with exporting to compressor (file already exist) I read I had to unistall any antivirus...and I did. But...is it normal to have a window showing the frames being compress by compressor when I press summit?

I'm doing experiments to try to understand but it will save me a lot to hear from more experience users..

Please help.

sorry for long post.
Osma

Have a G5 dual core,2ghz
 
yes, the frames window is normal.

how long was your original FCP6 capture project? 20 minutes or less, I'd think.

The 90 minute setting only dictates the overall compression ratio -

at first glance, Compressor will take a 5 minute FCP timeline and compress it to 5 minute mp4/ac3 files. It will seem to do the exact same thing as if you select the best 30 minute option -- but the compression ratios will be different.

You see, by selecting between the 90minute and other duration options, you're in fact telling Compressor how many minutes you want eventually to squish onto your DVD. If it's 30 minutes or less, Compressor will squish everything less. If 90 minutes, Compressor will squish more.

The actual clips should play for the same durations they went into the program, providing that you've not done any accidental frame rate/sample rate conversions while you put them in.

so...

did you try playing the file as is in FCP from the top to the bottom?
correct length? correct playback (no stutters, etc?)

Are your easy (>Q) settings correct? 1080p30 etc?

do you have access to another system to try? imovie and idvd, for instance?

I'd check that all your settings are consistent (1080p30 for everything, non-drop etc) for all programs.

The next thing is that you may have re-interlaced your clip. That's happened to me before. You get these wavey artifacts that look pretty bad if you don't tell all programs involved that it's progressive footage you are loading.

I don't think this is virus related, as we've had similar problems over here. G5 dual 2GHz PPC machines, same as yours, but FCPS1 (5.1.4), not S2.

HTH
Cheers
Chris
 
thanks Chris for your replay. I'm reporting back.

The lenght is not an issue and I do understand about the 90min setting.

FCP setting I use is DV NTSC 48khz...since I use SD DV footage..I think you thought I was doing HD. my bad...I didn't said. DVDSP is just set to SD DVD. I don't think there is a different setting for progressive with any of this.

I did a whole bunch of test now and I'm still doing more but so far I have no idea why sometime the mpeg-2 result is so bad...I got it to work sometimes with better results...meaning less jitter, where whole images shakes funcky...but still is very blocky an stuff. I playe with lowering the max bit rate and it does better also the best or better quality....sometimes it works better than others..I'll do more test and will choose the best from htem to do my project...an hope it works.

I thought I could just export to compressor choose best quality 90min setting and voala' great looking movie...but this is not like that at all. is it me? are other people working fine with this?

Please any help will aliviate.

my best to all
osma
 
Osma:

If what you mean is a lot of sort of "pulsing" or "throbbing" motion in the frame, especially in dark areas, it may be a noise issue that's just exacerbated by the compression process.. and it's best taken care of before compression. Often, just crushing the blacks a bit will solve this type of problem. Sometimes, encoding at LOWER quality and LOWER bitrate will help... the compressor will no longer bother trying to carefully encode all the noise in the background.

The main thing is to monitor accurately while editing, and make sure that you don't have too much noise in the dark areas. Often, people watch the encoded DVD on a TV with drastically different image rendition than the editing system, and are surprised by how noisy things are...

So, in short - try crushing the blacks a bit.

-Barry
 
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Hi Barry.

That is great info for me. explaining the "pulsing or throbbing" motion really helped me. I'll work on the blacks. Is that NOISE something I could eliminate while shooting or is that a normal noise that camera creates when dealing with blacks? DVX100A.

Just one more question. exporting to compressor and using best 90min settings makes a movie with jitter, jump it, stutter...image. Is that normal? is it because the 7.0 bitrate? I think I hear other people just use this and it works for them. curious..

OK, I'll work on crushing the blacks.
Thanks for all your help.

Osma
 
Jitter, jump, stutter... doesn't sound right. It SHOULDN'T be the case; I use the same bitrates as the 90 min preset often, and sometimes much lower. However, without seeing either your material or the compression result it's hard to tell. Can you try and describe the material a bit?

Also, I find that often 1-pass can give a better result than 2-pass... especially with noisy source material.
 
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How are you looking at your resulting video?

Have you made a DVD and checked the result on your TV or are you playing back the m2v file from your computer?

If the last is the case, try the first and report back.

Cheers!

Gunleik
 
reporting back.

I made a new DVD, this time I exported from FCP as quicktime, imported to DVDSP and encoded at 5.8/6.8 max bit rate, 2 pass VBR, motion better. The result..the image quality has improved a huge deal...looks great. but the problem came back again. all is looking good and out of the blue it starts twitching, it does for a short time and then good again..but it comes back. I even heard a crack in the sound once or twice. jerking twitching.... bad...less than before thou.

Some info.

Video I took with my DVX100A at 30p SD, nothing more. It is a dance concert. the whole evening lasted 1 hour, and there were 4 different choreographers. So, I imported to FCP separated the 4 pieces in 4 timelines and did the steps to DVDSP. I made titles in Motion and add it to the dvd. That's it.

I checked on my computer and burned a copy and tried in a dvd player and a laptop.

weird stuff. this last DVD I tested it. the first piece was fine, no problem...but..when the second piece started twitching i thought it had to do with a section being overexposed but realized i was wrong when other pasts were twitching as well as the other 2 pieces in the dvd.

have no idea why. but I think is better than using compressor. Iwill do 2 more tries 1. with lower bitrate 2 with one pass. and if this doesn't solve it. I guess I'll have to use iDVD or something like that. I have to deliver DVD on Tuesday and I'm very tired of reapiting this.

thanks to you for feed back. thanks a lot.

Please, any ideas why this is happening?
osma
 
Can we establish that the twitching is repeatable on defferent playback systems? That is, are you getting the same twitching in the same place when playing the same DVD in different players (e.g., laptop and DVD player)? It almost sounds like your DVD player may be skipping - which may have improved because of a lower bitrate, but shown up again under VBR encoding at some later part of the video...

Some DVD players don't handle high bitrates on recordable DVDs well...
 
yes...twitching in the same places...on my cheap dvd player, on my dual core 2.0 Ghz G5 desktop and on my powerbook G4 laptop. I thought about that possibility but I'm afraid it is something else.

I just made a new dvd this time 5.1/6.0 max bit rate and still twitching. I will make one more with 1 pass only now.

I'll report.

Any other ideas?
this is weird.
thanks again
 
Hmmm... my last post disappeared... anyway, what I think I said was that

1) it may be a field dominance issue; and

2) that it may be due to using compressor presets from a previous version of compressor. What version of compressor are you using, and what versions were previously installed on your machine? If you get the same problems when using quicktime conversion instead of Compressor, then this is not likely the issue.

After these thoughts, I think I may be out, especially without seeing the footage! Sorry!

Hmmm... did you export as a self-contained quicktime file? Try that if h you haven't...

Hmmm....
 
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