NVENC/QSV Bug when rendering image sequence + HEVC media

ALO wrote on 2/20/2024, 12:06 PM

I'm able to recreate this with media created entirely within Vegas. For starters, I created a short (2 seconds) PNG image sequence of a default text media clip. When this image sequence is imported and then placed on the Vegas timeline preceding an HEVC file (I use 5K GoPro, but this also happens if I create a Main Concept HEVC 4K clip), renders using the NVENC or Intel QSV encoders garble and bleed the image sequence into the following HEVC clip.

Here's a screenshot of my timeline:

This doesn't happen when I switch to an AVC render, or a Mainconcept HEVC render. Maybe all those images are somehow being held in memory and then leaking into the render of the subsequent clip?

Current Vegas build, NVIDIA GPU

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Howard-Vigorita wrote on 2/26/2024, 1:05 PM

Not clear how you're setting up Vegas for image sequences. Way I've been doing it is to set new image length in Vegas preferences to 1 frame in length, enabling quantize to frames, and then dropping the image-sequence as a group onto the timeline. I set the Vegas preference to 0.050 to get 1 frame in a 29.97 fps project. Vegas performance with 16-bit lossless pngs was really terrrible, however. Took almost 10 minutes for Vegas to react to a 3 second sequence of 108 pngs being dropped onto my timeline. So I gave up on that in favor of converting the image-sequence into a lossless-hevc clip with ffmpeg and loading that instead.

Former user wrote on 2/26/2024, 6:22 PM

@Howard-Vigorita This particular problem has nothing to do with image sequences, it's just that's what OP was doing when he noticed the encoding fault. The first thing I did after replicating OP's problem was remove the 2 seconds of PNG's which in my case was 60frames, and replaced with a single png of 2 seconds and then a single jpg of 2 seconds, then a single AVC of 2 seconds, they behave identically.

RogerS wrote on 2/26/2024, 6:43 PM

It seems to be the juxtaposition of images, text and video one after each other causing this garbling of frames. Good question as whether it's a quantization image but if Todd is doing it to the frame level that's not the issue.

Unlike before dynamic ram preview doesn't seem to be involved (at least zeroing it out here has no benefit).

Howard-Vigorita wrote on 2/27/2024, 10:08 PM

@Former user What I see is that Vegas has issues with pngs. I was able to load an image-sequence of almost a thousand exrs onto a Vegas timeline, no fuss, no muss. While 108 pngs white-screened me for about 10 minutes before Vegas arose from the grave. Dynamic ram manipulation had no effect. The exrs and pngs were the same lossless 48-bit color frames.