I've tried every combination of h.264 available in every profile especially "native" which by context is CPU only and that makes the render incredibly longer to complete but in davinci resolve I am unable to totally disable gpu hardware acceleration at the program level. When I render task manager does not show GPU encode activity at all as well.

At this point I'm wondering if there's a technical limitation like I and B frames that I'm not in compliance with in the blu ray standard that I don't know about. That or I have to plug in another monitor into my motherboard HDMI port to enable the Igpu to choose that instead of this nvidia card, to see if that gets around the program level gpu selection lockout that it forces my nvidia card to be selected with.

I and B frames etc are way above my head. Anyway here's the media info from a compliant AVC stream from VP21 Sony AVC render just in case it contains any useful info.

In DR's Preferences / System (tab) / 'Memory and GPU' selection, have you tried unchecking all GPU Configuration options?

@Teagan Does Resolve have Blu-ray render templates or are you just trying to export something suitable with what's available? I've no experience with Resolve hence my question.

Either way can you post Media Info on one of your H264 files that DVDA insists on compressing. Playing around we may be able to find a solution.

In DR's Preferences / System (tab) / 'Memory and GPU' selection, have you tried unchecking all GPU Configuration options?

It doesn't let me uncheck and totally not choose any GPU, it forces me to check one manually or with "auto".

@Teagan Does Resolve have Blu-ray render templates or are you just trying to export something suitable with what's available? I've no experience with Resolve hence my question.

Either way can you post Media Info on one of your H264 files that DVDA insists on compressing. Playing around we may be able to find a solution.

I'm just trying to export something that works, davinci resolve doesn't have anything blu ray related.

This is the file that requires recompression. I've played around with CABAC and can choose that entropy mode instead of CAVLC which is not what dvda wants, but I can't manually choose how many reference frames I have, I can only get 4 or 3, but not 2 as in the dvda non-recompress files.

The only thing in the davinci manual that references blu ray for h.264 is related to CABAC entropy encoding, which I'm using and only using CPU encoding. I just don't have access to choose only 2 reference frames.

I've checked the reference frame number in MAGIX AVC/AAC renders that I've used for years in Vegas Pro and the reference frame number is always 4 - but that's for HD 25 fps projects, not 24 (23.976) fps projects. One of the failures of Resolve is its inability to render to an fps rate that is different to the fps rate of the media on its timeline - if there's a way to do this I'd love to know. I mention this because I just tried to render in Resolve 20.1 Studio a short 25 fps video (10 secs) to 23.976 fps but could not do so even after changing Resolve's Project Preferences to 24 fps - it just reverted to 25 fps. Not surprising in that a bit under 2 years ago I couldn't transcode 50 fps GoPro video to 25 fps in Resolve - but Vegas Pro could do that easily.

I've now found a 23.976 fps video and rendered it in Resolve to an H.264 HD AVC file (the result was 4 reference frames). It imported and played back in DVD Architect DVDA 6.0 - and successfully rendered to an .ISO file.

I've now found a 23.976 fps video and rendered it in Resolve to an H.264 HD AVC file (the result was 4 reference frames). It imported and played back in DVD Architect DVDA 6.0 - and successfully rendered to an .ISO file.

I mean all mine play in DVDA7 it's just I don't want it to recompress the video during the compiling process, which degrades quality a bit.

and successfully rendered to an .ISO file

@Dexcon Could you please confirm that this "rendering" involved recompression and was not just image creation?

@EricLNZ  ... I've checked that DR render again and, unfortunately, DVDA 6 did recompress it when rendering to the .ISO file.

Since then, I've done a lot of testing in DR 20.1 with rendering to H.264 25fps 1920x1080 .AVC using many different custom render settings - but DVDA still wants to recompress the Resolve H.264 renders each and every time - basically the same result as the OP encountered. In DVDA, I also tested what happens with changing "Use default bit rate mode - yes or no" in DVDA's Optimize Disc settings for the video - either way, recompression was still needed for those videos. I think that I'm out of ideas with DR rendering at this stage.

Well I've been playing around and thought I had a simple solution by rewrapping a mp4 file I created into a mts file with Shutter Encoder. It added okay to a new DVDA7 menu page with a thumbnail image created. In File/Optimize Disc it showed the video stream didn't need recompression. Great, but that was the end of the good news as thereafter when I tried to do anything I just got a blank preview, blank menu page and DVDA would go grey and give up. I also tried using tsMuxer to "rewrap" to a m2ts file and Shutter Encoder to convert (rerender) to a m2ts file. All files gave the same problem in DVDA. I subsequently discovered these files also gave problems in my VP21.

So back to the Blu-ray problem. @Teagan you mentioned that recompression with DVDA degrades the image. DVDA is now an old 32 bit programme. Yes it's 32 bit! I'd try converting the files to compliant streams or files using more modern software. You have VP19. VP has recently experienced improvements in its rendering but probably post version 19? I don't know as I've only recently switched from VMS17. Anyway you could try using VP19 to rerender one of your Resolve files to Blu-ray compliant files to use in DVDA. Is there any noticeable video degradation with these files?

... you could try using VP19 to rerender one of your Resolve files to Blu-ray compliant files to use in DVDA. Is there any noticeable video degradation with these files?

Just leading on from Eric's suggestion, if your Resolve projects are UHD (i.e. 3840x2160) - and UHD was mentioned in the original post - you could do an UHD render in Resolve and then import that UHD render into Vegas Pro to render to a DVDA compliant HD .AVC file. This way, you're rendering UHD to HD rather than HD to HD which should make video quality loss negligible - if any. I recently did this in Vegas Pro 22 when a 140 mins UHD project wouldn't properly render to HD .AVC. An UHD .mp4 render worked successfully and I then rendered that UHD .mp4 render to HD .AVC for use in DVDA. It worked out very well IMO.