Slowmo causes encoded MPEG stutter

[Andrew Leigh]

Hi,

I have recently completed a project that included numerous slowmotion clips. Some down to 20% of the original speed. I used Premiere to adjust the speed.

When playing back on the Premiere timeline all play smoothly. After MPEG-2 encoding only some of the slowmo clips exhibit an exaggerated jerkiness whilst others dont. It would appear as if slowed clips with minimal subject movement are not affected whilst slowed clips with exaggerated subject movement are affected.

Used the same settings successful with previous projects. I use the best default the Ligos plugin for Premiere offers at VBR average of 6Mb/s. Thinking this was too high I then encoded at a lower setting of VBR average of 4-5Mb/s with the same results.

I have also used the advice from my previous post and applied the concepts from "Configuring TMPGEnc for high-quality, DVD-MPEG-2" also to no avail.

Would like to keep the slowmo especially as the one is of the bride getting out of the car.

Any thoughts. Is the Canopus speed adjuster better?


Thanks
Andrew

[Rob Lohman]

I'm fairly certain that this is a problem with the Ligos encoder. It
just isn't that a great encoder. If you want to be sure check out
the demo version of TMPGEnc or CCE

Also telling what EXACT settings you used might help as well. It
might even be a simple case of field reversal etc.

[Andrew Leigh]

Hi Rob, thanks for that will be downloading TMPGEnc tonight. There is package that includes DVD Authoring with the encoder, think that will be my baby.

By the way my settings were:

Audio Stream : 384 kB/s
Motion Estimation : 18
Variable Maximum Bit Rate : 7200 kB/s
Optimised Quantisation Scale - Average Bit Rate (Min) : 2334
Optimise Qunatisation Scale - Average Bit Rate (Max) : 5504
Frame Sequence : I, B and P Checked
No. of P Frames : 3
No. of Q Frames : 2
Seq. header before every GOP : Checked
P Frame Motion Vectors : 32 for both V and H
P Frame Motion Vectors : 16 for both V and H

Cheers
Andrew

[Andrew Leigh]

Hi Rob,

Further to the above. Have downloaded the TMPGEnc encoder only which requires a .avi file. Under Premiere which file type do I use?;

a) Microsoft DV AVI (which uses the microsoft compressor)

or

b) Microsoft AVI (which uses my Canopus DV Codec)

I think the answer is self explanitory and is option b) but one can never tell.

The reason for the question is the "Disk Full" error message. Is it possible that my data drive I am writing to is FAT 32 and I am running into the 2 gig file limit ??

Cheers
Andrew

[Rob Lohman]

Either should work with the latest version of TMPGEnc. But it
never hurts to see which one does. If you are using fat your
limit will be 2 GB for the Canopus AVI (it will remain that even
on NTFS I believe) and I think 4 GB for the Microsoft one.

This yields 9 minutes or 18 minutes of a file. BUT, for testing I
would choose a small piece from the timeline that had the most
problems in your original encode and just test with that.

There is a way to frameserve from the Premiere timeline directly
into TMPGEnc, but that's a different story.

[Andrew Leigh]

Thanks,

let's master the basics first.

Cheers
Andrew

[Jon Yurek]

Did you have Premiere deinterlace the slowed clips? If you did (which you should, since it will look horrible if you don't), did you deinterlace the rest of it?

If you didn't deinterlace the rest of it, then your MPEG encoder may be doing an interlaced encode, which would make the normal parts look fine, but the deinterlaced parts look quirky and a little jumpy. This was a problem we had putting our movie out to DVD... a number of effects shots were deinterlaced and they ended up looking like crap on-screen.

Your options would be to use something else for your slow motion that will output a deinterlaced, good looking clip or to deinterlace your entire project and make a progressive MPEG.

[Andrew Leigh]

Hi,

The TMPGEnc encoder did the trick. Followed the guidelines "Configuring TMPGEnc for high-quality, DVD-MPEG-2" which worked. Went middle of the road with resolutions, could probably go higher. Used an average VBR rate of 5MB/s.

Thanks for the help.

Cheers
Andrew