h261dec: Fix context initialization sequence

ff_mpv_common_init sets s->context_initialized.

This fixes decoding of h261 in the cases where the demuxer
hasn't already set the frame size.

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>
aacps.c: Move large arrays to context to reduce stack usage.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
qdm2: Allow hard-coding VLC tables.

Also adds a lot of infrastructure necessary for it.
Some of it is a bit ugly though.
Increases binary size for hardcoded tables by about 12 kB,
which is about 15 kB from qdm2_table minus data and code
saved that was only used for creating it.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Merge commit '3bb465245fed6069512e6821000391beae8a6066'

* commit '3bb465245fed6069512e6821000391beae8a6066':
  h261dec: Fix context initialization sequence

See: 6c1ee1a11446abbe662fc89b9dff0f0a3d5fdd55
Merged-by: Michael Niedermayer <michaelni@gmx.at>