Chapter points on a FFmpeg encode

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MJS63
Posts: 22
Joined: Mon Oct 18, 2021 2:52 pm

Chapter points on a FFmpeg encode

Post by MJS63 »

What is the best way to be able to assign a chapter point on a cut with a FFmpeg UHD encode?
When picking chapter points on the Scenes window I'm limited on where the next Keyframe is on the encode,
will adding a "--scenecut " and "--rc-lookahead" to the script help?

Alexey Kolesnikov
Posts: 262
Joined: Fri Mar 01, 2013 1:03 pm
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Re: Chapter points on a FFmpeg encode

Post by Alexey Kolesnikov »

Frankly, I didn't get a clue what you are trying to do.
If you need to re-encode video into 2 parts, I would recommend cut it first using menu Tools -> Assets Splitter in KITe (preferred) or https://dvd-logic.com/archive/hd_splitter and then re-encode.
Best regards,
Alexey Kolesnikov

MJS63
Posts: 22
Joined: Mon Oct 18, 2021 2:52 pm

Re: Chapter points on a FFmpeg encode

Post by MJS63 »

I need to be able to place chapter points on an exact frame and not at the nearest Keyframe.
With DVD encodes you had to add the Chapter point to the encoder so the I-frame of the GOP would be placed on your Chapter point.
With Blu-ray encodes it was never an issue as you could pic any frame to place a chapter point on, with the FFMpeg UHD encodes I can only place a chapter point at the start of the nearest Keyframe.
I believe when you encode using a Ateme Titan file encoder you have to tell the encoder exactly what frames you plan on having your Chapter points on, 90% of the time a Chapter point will happen on a Scene cut, so that is why I thought adding --scenecut to the script will force the GOP to start at the beginning of a scene cut, and --rc-lookahead should help the accuracy of the encoder.

Alexey Kolesnikov
Posts: 262
Joined: Fri Mar 01, 2013 1:03 pm
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Re: Chapter points on a FFmpeg encode

Post by Alexey Kolesnikov »

One point - the encoder is x265. ffmpeg is used for yuv conversion.
If we are talking about chapter point in Blu-ray/UHD, it should be placed on a keyframe, otherwise verifier will fail and some players will have problem to get into this chapter.
Did I understand right, that you want to specify the exact location for some keyframe (mark some frame as key frame) to be able place a chapter here?
Best regards,
Alexey Kolesnikov

MJS63
Posts: 22
Joined: Mon Oct 18, 2021 2:52 pm

Re: Chapter points on a FFmpeg encode

Post by MJS63 »

Yes, I do need to specify the exact frame for some keyframes.
Normally @ 12 chapters on a 120 minute feature.

Alexey Kolesnikov
Posts: 262
Joined: Fri Mar 01, 2013 1:03 pm
Contact:

Re: Chapter points on a FFmpeg encode

Post by Alexey Kolesnikov »

Possibly you can try to add --keyint 12 and --min-keyint 12 at the end of x265 settings https://x265.readthedocs.io/en/master/c ... ion-keyint
Best regards,
Alexey Kolesnikov

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