[XviD-devel] [RFC] resync markers in encoder

[Edouard Gomez]

Edouard Gomez (ed.gomez at free.fr) wrote:
> When do you think the encoder should add resync markers ?
> Should we add  a user setting to specify the number  of resync markers a
> frame ?

First I should mention the impact on encoding.
 - RD ME should then know where resync markers are planned so it can
   reset MV prediction on resync boundaries (hopefully, all get_pmv
   functions do support a bound parameter that i've never known its
   usage, now i know ;-)
 - Encoding loops must be slightly modified to:
    - reset AC/DC prediction on resync boundaries for IFrames (hre a
       bound parameter is also available on acdc prediction utilities,
       great :)).
    - reset MV prediction on boundaries.

So we have all we need in current code, the only missing bit is:
"When am i supposed to write these resync markers"

I propose to let the client app choosing, through a parameter called
max_resync_interval or a slice_length. Another possibility that could
dissociate the value of this parameter from the number of MBs would be
to use a number_of_slices parameter where:
 max_resync_interval = nb_mbs/number_of_slices;

Opinions ?

-- 
Edouard Gomez