asvenc: Forward the error instead of asserting on it

Bug-Id: CID 732997
CC: libav-stable@libav.org
svq1dec: Unbreak the scratch buffer allocation

The input packets are always assumed to be padded and
the av_fast_ family of function takes a pointer to a pointer.

Thanks to Nicolas Dufresne <nicolas.dufresne@collabora.com> for
a similar patch.

Introduced in 7b588bb691644e1b3c168b99accf74248a24e3cf.

Bug-Id: 766
CC: libav-stable@libav.org
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
vaapi: wrap codec specific functions in appropiate #ifs

Fix linking when only a subset of vaapi decoders is enabled.

Bug-Id: 760
CC: libav-stable@libav.org

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>