avcodec/mpegvideo: support disabling motion compensation

This allows analyzing videos without having prior and current frames mixed

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo: fix gray*() parameter types

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavd/opengl_enc: use flag to mark inited context

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavd/opengl_enc: add window size param

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavd/opengl_enc: fix window size correction code

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavu/opt: add av_opt_set_dict2() function

Existing av_opt_set_dict doesn't accept flags.
It doesn't allow to pass options to nested structs.
New function alllows that.

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavf/mux: pass options to nested structs of priv data

This commit allows to benefit from implementing child_next
callback for muxers' AVClasses.
Without that, options cannot be set in nested structs.

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
lavd/xv: reident after previous commits

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>
Merge remote-tracking branch 'lukaszmluki/master'

* lukaszmluki/master:
  lavd/xv: reident after previous commits
  lavf/mux: pass options to nested structs of priv data
  lavu/opt: add av_opt_set_dict2() function
  lavd/opengl_enc: fix window size correction code
  lavd/opengl_enc: add window size param
  lavd/opengl_enc: use flag to mark inited context

Merged-by: Michael Niedermayer <michaelni@gmx.at>