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[BUG] x264 open_gop error in Scenarist BD
#1
Enabling the open_gop parameter in Hybrid (2024.09.29.01) for disc authoring using x264 results in this message when importing in Scenarist BD

"ERROR : The number of fields(frames) displayed in a GOP exceeds the limit."

Disabling the parameter allows for import of the file into Scenarist.

Other encoding tools such as TMPGenc allow for open_gop=1 encodes to be imported into Scenarist so I feel something is wrong with the implementation within Hybrid (I know there are three modes for open_gop in x264 with one being meant for blu-ray specifically, maybe that's the issue).

It would also be nice to have an option for rc_lookahead=24 since that's the norm on blu-ray.


Thank you for all the hard workPlease, read the 'Infos needed to fix&reproduce bugs,..'-sticky before you post about a problem.
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#2
Maybe some user who uses Scenarist BD can help.
I don't own or use Scenarist BD and with the given information, this seems like you missed some restriction of Scenarist BD in your settings.

Enabling 'open_gop' by far is not enough for Blu-ray compatibility.
I assume you read https://forum.doom9.org/showthread.php?t=146199, https://forum.doom9.org/showthread.php?t=164759 and similar information. Assuming all other settings are properly set for Blu-ray compatibility, my guess is that it's a compatibility issue between Scenarist BD and x264 and not Hybrids fault.

x264s rc_lookahead can be configured in Hybrid ('x264->Rate Control->Rate Control Settings->Lookahead (frames)'), but it should not have an impact on compatibility.

Cu Selur
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Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.
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#3
I do not believe it to be a compatibilité issue with x264 and scenarist as TMPGenc runs on x264 and allows for open_gop=1 to be used on blu-ray.

Most discs out there are authored using Scenarist and pretty much any that have the x264 parameters available use open_gop=1

I have tried changing and enabling/disabling many settings for output and through the process of elimination I determined open_gop=1 in hybrid is the problem.
Without it enabled, I can very much import files in Scenarist without issues.

According to http://www.chaneru.com/Roku/HLS/X264_Set...m#open-gop there is a "bluray" mode for encoding with open_gop which indicates "Open-GOP enabled. A less efficient version of open-GOP, normal mode doesn't work when authoring Blu-rays.".

I believe this might be the root of the issue rather than incompatibility between x264 and Scenarist due to how widespread the usage of both software in tandem is.
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#4
Assuming you enabled Blu-ray compatibility (in Hybrid, with adds '--bluray-compat'), x264 should not create non-compatible files.
Open gop is allowed and often used on Blu-rays.
=> can't see a bug or Hybrid at fault here with the given details

Cu Selur
----
Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.
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#5
Enabling the blu-ray compatibility setting in Hybrid actually does not yield fully compliant encodes.

The default settings when enabling Hardware: Blu-ray/AVCHD for instance lack the Multi-slice setting set to 4.
Importing such an encode into Scenarist BD will result in the following message

ERROR: The picture is not encoded as multi-slice picture with 4 or more slices per picture in case of Level 4.1.(Slice:1)

Other authoring softwares that are more lenient might allow such encodes, but currently enabling the blucompat setting in Hybrid does not provide encodes that can be imported in Scenarist BD
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#6
Found something about that over at https://forum.doom9.org/showthread.php?t=143235
=> I'll adjust Hybrid to check that slices is set to 4 when Blu-ray compatibility is enabled. Smile
Also, neither Hybrid nor I claimed to be Scenarist compatible. Like I wrote before, I don't have access to Scenarist (+ it's ages since I used it).

Cu Selur
----
Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.
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#7
Uploaded a new dev version, which:
a. by defaults sets Multi-Slice to 'restricted by slices per frame' with a value of 4 when hardware compatibility is set to 'Blu-ray/AVCHD'.
b. if x264 encoder with hardware compatibility set to 'Blu-ray/AVCHD' is used, it also outputs a message to the log that for Blu-ray compatibility 4 slices are needed.
Since Hybrid does not know whether 'Blu-ray' or 'AVCHD' content will be created, it won't output an error, so the user still needs to know what he is doing.

Cu Selur
----
Dev versions are in the 'experimental'-folder of my GoogleDrive, which is linked on the download page.
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#8
Thank you for your hard work  Smile
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