Masking and Dynamic Ram Preview Max to 0 slows V16 NVENC render time

3d87c4 wrote on 9/15/2018, 3:40 AM

Sorry...it's about 1:30 am & I've been hacking at this most of the afternoon, so I'll post a summary now and will elaborate tomorrow if needed.

I've been using Vegas to create 3D 360 VR videos (3840x1920) for a while now. One of my steps, after stitching the 360 video, is to use masking in Vegas to hide my tripod. Basically I place the left eye clip in one track, the right eye clip below it, and create a negative mask around the tripod in the top track to expose the a portion of the second that doesn't have a tripod in it due to parallax. Then do the same thing with the right view on top, and left view below.

Anyway...I've been setting up the masking projects in SV13, then rendering them in V15 to take advantage of the faster NVENC rendering times. Today, I tried rendering in V16 and found the NVENC render time was about the same as when I rendered in V13!?!?!? Rendering times in V15 are about 1/3 the V13 times.

I did a bunch of experiments---single clips, two clips in a batch render V2 script, single clips with masking---and found the masked clips triggered the difference.

I compared render settings, to no avail, then reviewed my options/video preferences. V13 and V16 had Dynamic Ram Preview Max set to 0. V15 has it set to 200. When I set V16's value back to 200 ( I changed it to zero a day or two ago chasing another issue. ) the V16 render times are comparable to V15.

G'night.

Comments

Former user wrote on 9/15/2018, 6:40 AM

Good point. That info should be known to those that set the ram value to 0 trying to avoid vegas crashing.

I have it set to 2048 as I often repeatedly playback the same part of a timeline & the ram preview things seems to be activated automatically, & and as you said if it's reduced below default, especially below 100 it can affect render speed.

bitman wrote on 9/15/2018, 12:18 PM

With each new Vegas release I am very suspicious about using the infamous Vegas Dyn. RAM setting. I had such bad experience in the past with my large memory NVIDEA cards (titan-x and 1080ti ) rendering with anything other than 0 would sometimes cause issues such as crashes or corruption. And this with different PC hardware mobo's and video cards. Setting it to zero does harm however a bit the render time (as does overdoing it). Here are some NVENC render times of the same project with different Dynamic RAM settings:

0 (Dynamic RAM) --- 41 s render time
100 ----------------------- 35 s
200 ----------------------- 35 s
400 ----------------------- 35 s
4092 --------------------- 39 s
8000 --------------------- 40 s
16000 -------------------- 40 s
32000 -------------------- 41s

bitman wrote on 9/15/2018, 12:23 PM

@3d87c4 Just a crazy idea, ever thought of painting your tripod in some green screen color and green keying it away?

OldSmoke wrote on 9/15/2018, 12:47 PM

@3d87c4 Just a crazy idea, ever thought of painting your tripod in some green screen color and green keying it away?

Why would the tripod be in the picture?

3d87c4 wrote on 9/15/2018, 12:50 PM

I'm still a bit of a novice vis-a-vis Vegas compositing and have had mixed success using green screens.

The masking trick works & is a common trick for hiding tripods, AFIK. The main issue I've had with it is that it isn't compatible with cross fades---the mask edge always shows up if you cross fade a masked clip---so I do an intermediate render. For my last few videos I tried nesting Vegas files, instead of intermediate renders, but this means I can't use proxies in my final project and the final render times are very long.

Yesterday's fire drill was triggered by comparing renders with the Magix Intermediate and Magix AVC NVENC codecs. The render times were about the same and I couldn't see any difference in the results. (Load identical clips rendered by each codec into a 3D file, combine as a 3D pair, and display using the "Difference" Stereoscopic 3D mode.) In the process I noticed the AVC NVENC renders seemed longer than I expected, so tried a V13 Mainconcept render.

3d87c4 wrote on 9/15/2018, 1:10 PM

"Why would the tripod be in the picture?"

The field of view of the Vuze lenses is a bit over 180 degrees, so it will pick up tripod legs and handles. I hide the legs with a "patch"---a round graphic---but still have to mask away the handle. I simply bent the handle on another tripod...

So, I fibbed a little in my earlier posts. The clips I was masking yesterday were shot underwater, so I am masking away the selfie stick I'm using to hold the camera. I'll mask the tripod in my surface clips in a day or two.

With the selfie stick:

Mask:

Result:

3d87c4 wrote on 9/15/2018, 1:36 PM

Here are the render times for a few cases (Mainconcept & Magix AVC NVENC):

Another clip was taking 30 to 40 minutes to render!!! I have 78 clips to process, so need the shorter render times.