[x264-devel] Re: [PATCH] Forcing frame coding as IDR

[Loren Merritt]

On Mon, 4 Jun 2007, Jingyi Hu wrote:

> It all depend on the clips and output frame location:
> 1)If all clips contents are not all related, the separate encoding will make 
> more efficient in coding mv search, reference frame search etc.

If clips contents are not related, then x264's scenecut detection will 
trigger and put a keyframe there anyway. The purpose of forcing keyframes 
is if the chapter break occurs somewhere that's not an obvious scenecut. 
e.g. frade to black, chapter break, fade in next scene.

> 2)If you do not have a IDR interval parameter setting and clips scene changes 
> a little, you will not have a IDR for a while. In this case, it will big 
> offset between IDR and require frame #.

Say in english please?

> 3)Usually end user do not have accurate idea about exact frame #. If you 
> force set the frame # become IDR, it will increase stream data overhead.

If the user doesn't know the exact frame numbers, how is he supposed to 
split the video either? And if you want some algorithm to find scenecuts, 
what's wrong with the current one?

> 4)The best approach to give the time duration or output bitstream size. Let 
> program determine which frame numbers are and carry the extract output.

How does time duration differ from frame number? Just multiply by fps.
And splitting by output bitstream size is a completely different goal.


P.S. please don't top-post, and please don't break threading.

--Loren Merritt

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