vaapi: return early from ff_vaapi_render_picture() without picture

Fixes an assertion when called on uninitialized frame. Spotted after
seeking in vlc.
Fixes ticket #2461.

Tested-by: Timo
Reviewed-by: Joakim Plate
Signed-off-by: Carl Eugen Hoyos <cehoyos@ag.or.at>
(cherry picked from commit 2ee380aefbb92c89e8e9c7aa5846aa404919ec7c)
swresample/x86/audio_convert: add emms to CONV

Fixes ticket #1874

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit ca2818b88155029bb6f989ee522e7f8e9e9f5927)
ff_gen_search: make step 64 bit to prevent hypothetical integer overflow

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 9d73e302537144877ca9d5b648b21aca28b78f4f)
ff_gen_search: fix limit

The limit value could become slightly wrong in the last iteration

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit b3dd50cd0dbbda08610b75384128f5f47f5199d9)
ff_gen_search: fix infinite loop

Fixes Ticket2639

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit f8ca8138f01d0a7d96d4e1ea65fecd1197f96206)
Autodetect idcin only if audio properties allow decoding.

Fixes ticket #2688.
(cherry picked from commit 06bede95fcea47d2e51e8ff248c15311f335b898)