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Old 28th June 2020, 22:07   #29515  |  Link
jdobbs
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Join Date: Oct 2001
Posts: 20,973
Looking at the output from NVENCC, I'm guessing (but only guessing) that this may be the issue:

According to "White Paper Blu-ray Disc Read-Only Format Coding constraints on HEVC video streams for BD-ROM Version 3.0", page 6, each GOP (Group of Pictures) of the HEVC stream must start with an IDR (of course) -- and will contain one SPS (Sequence Parameter Set), one VPS (Video Parameter Set), and at least one PPS (Picture Parameter Set), and no more than 30 PPSs.

In dumping out the HEVC stream I'm finding that only the first GOP (the first IDR frame and following P/B frames in the file) meets this requirement. All the others IDR frames (start of GOP) I've looked at only have an AUD (Access Unit Delimeter) and a couple SEI's (Supplemental Enhancement Information) preceding the IDR slice.

I'll have to do some finagling with the stream to find out if this is truly the issue -- but it could make sense and explain why the stream can start playing from the beginning (the IDR that has the required information) but can't step into any of the others (FF/REW and CHAPTER SKIPS).

You never know, this may not be the problem at all... but I guess I'm going to have to find out somehow. In X265 you create a stream that contains the SPS/VPS/PPS in every GOP by using the --repeat-headers command line option. I'm hoping the same thing can be done in NVENCC.

I've added this information to my Issue Report at GITHUB. Hopefully someone with a little more HEVC/UHD-BD knowledge than me can confirm or deny this as the cause of the issue I'm seeing.

[Edit] In the meantime, I'm going to see how hard it would be for me to to scan and insert the headers via a software routine -- or if it is even possible. Unfortunately that would require me to read through the entire HEVC file and write a new one -- which requires significant processing time. In the end I may find out it isn't even the problem!
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Last edited by jdobbs; 28th June 2020 at 22:52.
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