[theora-dev] [PATCH] thusnelda keyframe only speedup

[Philip Heron]

xiphmont at xiph.org wrote:
> On Sat, Mar 15, 2008 at 4:01 PM, Philip Heron <phil at sanslogic.co.uk> wrote:
>> Hi all,
>>
>>  Attached is a trivial patch that speeds up encoding for key frame only
>>  streams. It skips the motion vector search which is not needed when
>>  there are never going to be any delta frames. It was made against
>>  thusnelda SVN revision 14589.
> 
> The results of the current frame's (and previous frame's) MV search
> are needed by subsequent frames to seed constant speed and constant
> accelleration candidates.  That includes INTRA frames. This breaks
> that part of the analysis.
> 
> It would be valid to skip MV analysis on scene-change INTRA frames so
> long as you also reset the persistent MV analysis state, but it is
> incorrect behavior for INTRA frames forced by the keyframe max
> interval.

Is it possible to skip MV analysis completly as a speedup, and still 
produce a valid bitstream? Or am I barking up the wrong tree? I'm trying 
to encode full screen video (720x576x25fps) in real time for 
transmission on a LAN, so speed is more important than efficiency.

> That said-- I appreciate that others are looking at (and hacking on)
> the Thusnelda branch :-)

Hacking yes, understanding.. not so much ;-)

-Phil