avcodec/snow: check coeffs for validity

Fixes deadlock
Fixes integer overflow
Fixes Ticket 3892

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avfilter/vf_mp: remove incorrect usage of AVFrame.type

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/id3v2: Fix "warning: unused variable uncompressed_buffer_size" if zlib is unavailable

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/udp: Move variables used only with HAVE_PTHREAD_CANCEL, under the #if

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/aarch64/h264qpel_init_aarch64: mark src as const

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/vp3data: use more compact data types

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>