V4 and MainConcept MPEG2 encoding

dmcmeans wrote on 3/18/2003, 10:17 AM
I rendered a short clip with V4 using the MainConcept MPGE2 DVD separate streams template.

The resulting video's quality was "strobish(*)". I had this problem with V3 and MainConcept, but it seemed to "go away" after a while.

Now, at least for the moment, it's back with V4.

I don't remember what I did, if anything, to make it go away with V3. Anyone else getting this behavior (again)? Know the solution?

David

(*) strobish -- (1) a technical term describing MPEG2 video that so degrades on the delta frames that the video appears to pulse or strobe. (2) An elusive rendering issue that occurs with Vegas 3 and 4 and MainConcept MPEG encoder.

Comments

MCTech wrote on 3/18/2003, 2:00 PM
What format was the source material?
johnmeyer wrote on 3/18/2003, 3:39 PM
Could this be a field order issue?
dmcmeans wrote on 3/18/2003, 5:13 PM
Format was AVI. A couples of VisionSeries files from the sampler and some text. I first rendered to NTSC avi and then rendered that using the DVD separate streams template.

The strobing has to do with quality. You can see it go down as you move away from the I frame. Every 15th frame is good, all deltas get progressively worse, thus the strobing.

This is an old issue, I just don't remember what the solution, if any, was.

Oh well, I'll try the old reboot, re-install approach I guess.

MCTech wrote on 3/18/2003, 7:22 PM
What kind of AVI? AVI can be a wrapper for many different codecs. I'm trying to figure out whether the source material was already highly compressed, which could help explain this.

Also, is there any way you can send me a short sample of a "strobish" file (5 MB or less)? If so, please send to markb@mainconcept.com.

Hmm, I think I once knew someone whose last name was Strobish.
dmcmeans wrote on 3/18/2003, 8:44 PM
Boy ... feeling a little sheepish here. It was a DV avi file that I rendered my project to and from that I made the mpeg. Problem is, it's working now. Everything I render looks great, even reversing the field order looks good.

Despairing being able to reproduce this "problem" I tried the DVD PAL template out of desparation. Lo and behold, it creates an mpeg that looks like my "strobish" example.

What does this mean? Was I too tired because I was up until 1:30 AM playing with my new copy of V4 to know what template I was selecting so that I choose PAL what I wanted NTSC? I don't know. Would seem unlikely. But the fact remains that my "strobish" file is generatable by using the PAL template.

Curious.

Would I expect the PAL template to produce an mpeg that looks "strobish" when played with Media Player?

I've uploaded the "strobish" example to

ftp://flyingRiver.com/flyingRiverPro_Overture.mpg

Thanks for the quick response. Feeling little sheepish to have said V4 and MC have a rendering issue .... when it's looking more like pilot error.