[FFmpeg-devel] matroska encoder option -- force new Cluster on keyframe
nicolas.george at normalesup.org
Sun Jul 21 11:26:51 CEST 2013
Le tridi 3 thermidor, an CCXXI, Bernie Habermeier a écrit :
> This is why I think this should be an option, and one that you'd only turn
> on if you thought this was something that makes sense to you. Overall,
> when you transcode a movie, you have to make a lot of tradeoffs about size
> and quality. This option just allows you to make an additional decision
> regarding seek time efficiency -- for cases where you absolutely care
> about this -- perhaps on mobile devices.
Currently, the logic to start a new cluster seems to be:
* If the output file is not seekable (streaming/net), whatever comes first:
* after 32 ko;
* after 1 s.
* If the output file is seekable, whatever comes first:
* after 5 Mo;
* after 5 s;
* before a video key frame if the current cluster is already > 4 ko.
The most obvious seems to make all these values options:
(with a word in the doc that the max size/duration can be exceeded by up to
It would also probably be the easiest.
Note that the current logic seems to already implement what Michael and you
have been discussing: start a new cluster at each keyframe except if they
are too frequent (4 ko).
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