Bug? "Selectively pre-render Video" with MainConcept MPEG-2 format

RichMacDonald wrote on 10/26/2002, 4:59 PM
In a followup based on a suggestion in the thread http://www.sonicfoundry.com/forums/ShowMessage.asp?MessageID=132505&Replies=6&Page=6 I attempted to "print to tape" and/or "pre-render video" as a way to be able to temporarily stop rendering without losing all the work to date. I found what appears to be a bug in the latest VV3.

"Print Video to Tape" only allows DV format, so I cannot pre-render my mpgs this way.

Choosing "Selectively pre-render Video" with a MainConcept MPEG-2 format "DVD NTCS" template goes through the initial setup then gives me an error that "cannot be determined". I get a cascade of errors: one for each xxxx file that would have been created...

Choosing "Selectively pre-render Video" with DV format works fine. Choosing "Selectively pre-render Video" with MainConcept MPEG-1 format works fine.

Interestingly, doing a "Preview in Viewer" with the MainConcept MPEG-2 format "DVD NTCS" template worked fine.

Error occurs whether or not the entire file is being rendered or just a selected portion.

So if anyone has a moment to verify this (VV bug or personal problems :-) I would appreciate it: Choose "Selectively pre-render Video" with a MainConcept MPEG-2 format "DVD NTCS" template and see what happens. TIA.

Comments

SonyEPM wrote on 10/27/2002, 12:40 AM
I'll try to repro this...

Are you trying to render portions of what will eventually become a DVD MPEG file? That will not work. MPEG prerenders will not (from Vegas at least) be joined into one monster MPEG file. You'll be rendering everything again from scratch (not using the prerendered MPEGs AT ALL) when you render-as at the end of the day.


Also: I've tried "joining" multiple DVD MPEGs with probably 6 different non-sf apps (TMPEG etc) and I've always had a glitch or an a/v sync issue. The UI is there for it in TMPEG, but getting it to work perfectly is another matter. Anyway if you end up trying to go this route be forewarned- it doesn't appear to be a no-brainer process. It could be operator error on my part...let me know if anybody gets this to work consistently and reliably.
RichMacDonald wrote on 10/27/2002, 11:36 AM
>I'll try to repro this...

Do it for your own interest. The technique isn't going to be useful for me, see below:

>Are you trying to render portions of what will eventually become a DVD MPEG file? >That will not work. MPEG prerenders will not (from Vegas at least) be joined into >one monster MPEG file. You'll be rendering everything again from scratch (not using >the prerendered MPEGs AT ALL) when you render-as at the end of the day.

Yup. Thanks for this post. I went back and performed my test using MainConcept's MPEG-1 as well as DV-NTSC formats and you are correct. Pre-rendering is ignored when one does a final render. So this approach will not work as a way to incrementally render a large file. Which makes me wonder what "Selectively Prerender video..." is useful for, but that is another story :-)

>Also: I've tried "joining" multiple DVD MPEGs with probably 6 different non-sf apps >(TMPEG etc) and I've always had a glitch or an a/v sync issue. The UI is there for >it in TMPEG, but getting it to work perfectly is another matter. Anyway if you end >up trying to go this route be forewarned- it doesn't appear to be a no-brainer >process. It could be operator error on my part...let me know if anybody gets this >to work consistently and reliably.

I have the same problems. Actually, I noted this in the original thread. I have always assumed this was because the "split points" are arbitrary (i.e., any frame we choose) while the mpg format is "chunked" (i.e., can only be written as groups of frames due to the compression scheme). So it is highly unlikely that we are going to pick the "right" split-frame that perfectly aligns with the mpg frame. Consequently, a glitch at the join point.

At this point, I am back to reiterating my feature request: I'd love to have a "background render queue-er" which renders a queue of files in the background and is able to stop and restart (say from an OS crash) without having to go back to the begining.