OK, but I'm foggy on one thing. If I print from the timeline to tape, and later render the timeline (not the resulting avi but the same timeline again) to an MPEG-2 file headed for DVDA2, am I converting recompressed FX and color correction due to the earlier timeline-to-tape print?

I'm not really thinking this through clearly enough to give a definitive answer, but then again even if i was completely lucid probably the only folks who could give a definitive answer are the software developers. But, here's my thought ... your later render from the timeline will in no way be affected at all by previous renders, nor should they be. Each time you render Vegas will start from scratch. Even if you had prerenders, rendering to a different format would invalidate those prerenders and they will be ignored.

Cunhambebe:

That's a new one on me. I've taken a vob file from a finished DVD, worked it over in Vegas, and re-encoded it to MPEG2 without getting the banding you describe. I use the CinemaCraft MPEG2 encoder, but can't see why the MainConcept encoder would create banding...

riredale wrote:
I've taken a vob file from a finished DVD, worked it over in Vegas, and re-encoded it to MPEG2 without getting the banding you describe.

-In fact I use TMPGENC (I render Vegas timeline tru Debugmode plug-in). Even trying Main Concept, the result is the same: banding. Try to resize a commercial VOB from 16:9 to 4:3, edit it and give it a final render as MPEG2. You'll see what I'm talking about. This issue has been discussed at VideoHelp and no one seemed to have a definitive answer. Some users told me to use a TMPGENC option (deinterlace - even field adaptation), but it didn't worked for me. On the other hand, dithering did it.

All this while, I seem to be under the similar impression that DV in PAL lands is 4:2:0, DV in NTSC lands is 4:1:1 and DVD MPEG2 is 4:2:0, too.

Also, Vegas seem to perform all internal processing at 4:2:2. However, generally saying, going from Vegas timeline to standard DV then to DVD MPEG2 seems to suggest that the final output would have gone through 2 different passes of compressions (standard DV and MPEG2 are lossy compressed formats.. with one at approx. 4:1 compression ratio and MPEG2 at various:1 compression ratio.. I think.. Age has pretty apparent effect on my human CPU and RAM..).

Color information lost can not be recovered; secondary information discarded by standard DV and MPEG2 lossy compressions can not be recovered as well. Therefore, if going from Vegas Video to DV to MPEG2 is necessary, it'd be better to make sure the video goes from Vegas timeline to uncompressed DV (with huge monster file size) to MPEG2, without further pixel modification of the uncompressed DV.

Take note, however, that going from Vegas timeline to standard DV to MPEG2 will not affect unmodified standard DV footage (with no color correction, pan/crop and etc), it is only generated medias may suffer mild information loss (due to the recompressions and discarded information).

I may got careless with some of the details. Please let me know if I make any bloopers with the infos. Thanks a bunch, foks.

Cunhambeb, are you referring to the banding of the graduated colors we looked at some time ago? If not then does it look like bad interlace artifacts? If so then it can be cured by turning on Reduce Interlace Flicker.
If it is the effect in graduated areas of color then I'd say what you are seeing is precisely what SPOT was talking about. I suspect though the problem is you've been through several color space conversions. You've gone from 4:2:0 -> 4:1:1 -> 4:4:4 - >4:2:0. I'd be interested to know though if the problem doesn't occur if you don't change the AR.
Having read through some of the referenced literature what also interests me is that the 4:2:0 sampling in mpeg is not the same as that used in DV, I'm wondering what possible implications that has.

farss wrote:
"Cunhambeb, are you referring to the banding of the graduated colors we looked at some time ago?"
-YES, YES!

If not then does it look like bad interlace artifacts? If so then it can be cured by turning on Reduce Interlace Flicker.

-It doesn't look like artifacts, but banding. Reduce interlace flicker? Forget it! I've already tried that. If you search for my user name at VideoHelp, you'll see a pic there.

If it is the effect in graduated areas of color then I'd say what you are seeing is precisely what SPOT was talking about. I suspect though the problem is you've been through several color space conversions. You've gone from 4:2:0 -> 4:1:1 -> 4:4:4 - >4:2:0. I'd be interested to know though if the problem doesn't occur if you don't change the AR.

- I've already tried dropping the VOB file directly onto Vegas timeline, edit and render it as MPEG2. The result? Banding! (Hope you've read that I had resized the VOB file...I suspect that it could be that)

Having read through some of the referenced literature what also interests me is that the 4:2:0 sampling in mpeg is not the same as that used in DV, I'm wondering what possible implications that has.

- I do remember you sent a couple of e-mails 2 months ago.......Another aussie fella, told me to get TMPGENC and "turn on" deinterlace - even field adaptation......
No way! The final result was the same: banding :(

So does this mean you are taking a colorspace hit if you use distributed network rendering on FX before encoding to MPEG-2?

Network rendering, I believe, uses the DV codec as an intermediary step prior to stitching, right?

i dont see how it could be using a dv codec for network rendering - as i am rendering to a codec in sizes like 1280x2048 and dv doesnt support those resolutions ...