Nested veg files and slow renders

jeffhar wrote on 3/13/2018, 2:23 PM

Vegas Pro 14 build 270 64-bit

Long ago (circa 2010) one JasonATL described on this forum a problem with nested projects, brought in as veg files, causing very slow (e.g. 10x slower or more) render times in the parent project. There wasn't any solution offered at the time and I bumped into this same thing with Vegas Pro 14 recently.

My child project, which is a bunch of jpeg images combined with track motion, renders in around 44 s using the Main Concept AVC/AAC Internet HD 1080p render option. This matches the child and parent project settings so there is no difference in resolutions, frame rates, etc. When the child project is imported as a veg file into the parent project and rendered, it takes over 7 minutes! Further, I have observed the same problem described by Jason with the child render using nearly 100% of the CPU whereas the parent project struggles along at below 30% utilization (i.e. apparently not using all the cores). Using GPU Acceleration option or not doesn't change the results.

My question to the forum - is there some setting I am missing that solves this issue? Are nested projects actually usable in Vegas Pro for large projects? Alternatively, I could render out the child (e.g. to mp4) and then put that into the parent (which indeed then renders quickly) but I worry about multiple iterations of compression degrading the result. What to do for a large complex project?

Comments

Former user wrote on 3/13/2018, 4:18 PM

I do not like nesting for some of the reasons you have discovered. If you don't want compression degradation then render to either uncompressed or lossless compression. Don't use MP4 as interim files.

jeffhar wrote on 4/5/2018, 3:24 PM

Thanks david-tu. Anyone else?

After poking around I eventually gave up on using Vegas nested projects and instead used the Sony MFX > HD422 1920x1080-60i 50 Mbps render profile to generate near-lossless renders for the sub-projects that were then imported into the master project. Done this way the master project renders were fast and reliable. Not quite as convenient as nested projects but it works.

Curious that some seem to be using nested projects without complaints about slow render times. I wonder if others have looked at their CPU usage during nested project renders?

john_dennis wrote on 4/5/2018, 5:31 PM

I neither love nor hate nesting, but rather use the process when it makes my life simpler. I most often use nesting for:

1) complex repeatable graphics

2) unusual pixel aspect ratios

Usually, when I start a render, I don't sit and stare at the progress bar but consider doing something else. I ran some tests on Vegas Pro 14-270 using AVCHD 1440x1080-29.97i source material from a 2011 project. I rendered to the Mainconcept AVC Sony Tablet 1080p and the Internet 1080p templates. There were four renders in all, two from the original project and two with the original project nested in a 1920x1080-29.97p project.

Mainconcept AVC, Sony Tablet 1080p 

Mainconcept AVC, Internet 1080p

I have no doubt that users have had issues with nesting, but for these tests render performance doesn't appear to be an issue.