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+--- Thread: [BUG] x264 open_gop error in Scenarist BD (/thread-3948.html)
x264 open_gop error in Scenarist BD - Prince7 - 12.12.2024
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.
RE: x264 open_gop error in Scenarist BD - Selur - 12.12.2024
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
RE: x264 open_gop error in Scenarist BD - Prince7 - 12.12.2024
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_Settings.htm#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.
RE: x264 open_gop error in Scenarist BD - Selur - 12.12.2024
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
RE: x264 open_gop error in Scenarist BD - Prince7 - 12.12.2024
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
RE: x264 open_gop error in Scenarist BD - Selur - 12.12.2024
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.
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
RE: x264 open_gop error in Scenarist BD - Selur - 12.12.2024
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
RE: x264 open_gop error in Scenarist BD - Prince7 - 12.12.2024
Thank you for your hard work