# [FFmpeg-devel] matroska encoder option -- force new Cluster on keyframe

Nicolas George nicolas.george at normalesup.org
Sun Jul 21 11:51:53 CEST 2013

Le tridi 3 thermidor, an CCXXI, Bernie Habermeier a écrit :
> But I explicitly WANT to have an option that doesn't "take it under
>
> Specifically, I want to control exact placement of my I-frames, and
> therefore CuePoints, and I want to a 100% guarantee that I have a new
> Cluster start for each such CuePoint.  What you're proposing does not do
> that at all, and has a completely different feel to it.  We can certainly
> add this kind of control, and I'm fine implementing that, but that is
> specifically not what I want.

I am not sure the direction of your requirement, but I believe the current
logic with configurable limits would work for both:

* Positive: if you WANT a new cluster for each key frame, irregardless of
the size/duration/age/whatever of the current cluster, -min_cluster_size 0
(instead of 4k) should do that.

* Negative: if you WANT NO new cluster except at key frames, then
-max_cluster_size \infty -max_cluster_duration \infty (instead of 5M/5000,
or 32k/1000 for streams) should do that.

(lavf does not have \infty, but INT64_MAX should do the trick unless you
intend to produce a eight etaoctets file longer than the history of
mankind.)

And of course, if you want both, you set all these options like that.

Am I missing something?

Regards,

--
Nicolas George
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