1) create BluRay complaint 1080p stream, with "1 sec" GOP (30 frame) for std 29.97 video.
2) bring up SmartRender, add the clip, then in the "Format" panel click "Start Analysis". Notice it wants to render the first 2 sec. Now output the file and it creates a 61 frame GOP out of the original 3 GOPs (1, 30, 30).
3) This re-rendered file is now not BluRay compliant.
[...]
if you bring up a Vouk or FFMpeg NVENC clip in SmartRender, enable "show frame status", you'll see the solitary I frame followed by the regular GOPs ... and a blank audio frame.
I don't observe any frame-order problems with video files rendered by Vegas 20 using Voukoder/VoPro. Following the steps quoted above (except using GOP 60, which is actually the Blu-ray max for 29.97p video, and my preferred setting), the first few frames of the video are as follows, starting with frame 0: IBPBP.
Switching to your setting of GOP 30, Smart Renderer now wants to re-encode most of the video file for whatever reason (see screenshot). But the frames still remain in the correct order (IBPBP), with no extra I-frame. I assume you have a reason for rendering as GOP 30, so I'm not going to address that.
Tested some 1080p23.976 GOP 48 renders, and they cause no problems either.
I suspect, as stated before, that your problem may lie with Premiere or your settings therein. AFAIK, FFmpeg just encodes whatever frames it's fed.
See screenshots below. TMPGEnc Smart Renderer 6 doesn't complain about the video stream at all using GOP 60.
These files were encoded using Vegas Pro 20 build 411, Voukoder 13.3, connector 1.7.1, NVENC h.264. I modified a preset I normally use for Blu-ray encoding, just changing frame rate and GOP size. Normally I run 1080p23.976 GOP 48 which is fully Blu-ray-compatible.
GOP 60:
GOP 30:
