[NUT-devel] r20981 - trunk/DOCS/tech/nut.txt

[Oded Shimon]

On Fri, Nov 17, 2006 at 01:44:10PM +0100, michael wrote:
> Author: michael
> Date: Fri Nov 17 13:44:10 2006
> New Revision: 20981
> 
> Modified:
>    trunk/DOCS/tech/nut.txt
> 
> Log:
> seeking

This probably belongs better in the nut-english.txt doc in NUT repo...

> Modified: trunk/DOCS/tech/nut.txt
> ==============================================================================
> --- trunk/DOCS/tech/nut.txt	(original)
> +++ trunk/DOCS/tech/nut.txt	Fri Nov 17 13:44:10 2006
> @@ -901,6 +901,29 @@
>  search at a particular offset when any startcode is found (including syncpoint)
>  
>  
> +Seeking without an index (non-normative):
> +-----------------------------------------
> +A. backward seeking
> +    1. perform a binary search on the syncpoint timestamps finding the one
> +    which is largest and <= the target timestamp
> +B. forward seeking
> +    1a. perform a binary search on the syncpoint timestamps finding the one
> +    which is smallest and >= the target timestamp
> +    1b. perform a binary search on the syncpoint back pointers finding the
> +    smallest one which has a back ptr >= the position of what was found in 1.
> +2. follow the back pointer to the correspoding syncpoint
> +
> +Seeking with an index (non-normative):
> +--------------------------------------
> +The demuxer only has to find the appropriate keyframe in the index and
> +start demuxing from the previous syncpoint
> +
> +Note, more complicated seeking methods exist which are capable of quickly
> +seeking to the optimal point in the presence of an index even if only a
> +subset of all streams are active but a muxer SHOULD place syncpoints,
> +and keyframes if it can affect the placement of keyframes so that simple
> +low complexity seeking works with fine granularity

I fail to understand this last part...

- ods15