4xm: more thorought check for negative index and negative shift

CC: libav-stable@libav.org
Bug-Id: CID 1087094
vp7: fix checking vp7_feature_value_size()

CC: libav-stable@libav.org
Bug-Id: CID 1197061
libopusenc: check return value

CC: libav-stable@libav.org
Bug-Id: CID 739870
libopusenc: prevent an out-of-bounds read by returning early

CC: libav-stable@libav.org
Bug-Id: CID 1244188
nellymoserenc: fix array element ordering

Fixes assertion failures and valgrind warnings in trellis encoder.

CC: libav-stable@libav.org
Bug-Id: CID 732256 / CID 732257
nellymoserenc: fix array index

CC: libav-stable@libav.org
Bug-Id: CID 732258
display: fix order of operands

CC: libav-stable@libav.org
Bug-Id: CID 1238828 / CID 1238832
dnxhdenc: check negative index

CC: libav-stable@libav.org
Bug-Id: CID 700464
vc1dec: always initialize tx and ty

CC: libav-stable@libav.org
Bug-Id: CID 1245702 / CID 1245703
vc1dec: refactor check with missing parenthesis

FATE tests updated accordingly, no visual difference.

CC: libav-stable@libav.org
Bug-Id: CID 1087087
sunrastenc: mention missing break

Bug-Id: CID 732231
dpxenc: mention missing break

Bug-Id: CID 732229
vorbisenc: add missing parenthesis

Bug-Id: CID 1238791
ffv1: fix out-of-bounds read

CC: libav-stable@libav.org
Bug-Id: CID 1047234
mlpdec: check for negative index

CC: libav-stable@libav.org
Bug-Id: CID 970924
escape124: explicitly set get_bits1 variable

Makes coverity less confused.

CC: libav-stable@libav.org
Bug-Id: CID 1203487
dcadec: initialize variables before use

CC: libav-stable@libav.org
Bug-Id: CID 700751 / CID 700752
shorten: check for return value

Avoid a possible negative bitshift.

CC: libav-stable@libav.org
Bug-Id: CID 1194400
indeo3: check ff_set_dimensions return value

CC: libav-stable@libav.org
Bug-Id: CID 1135740
g2meet: check ff_set_dimensions return value

CC: libav-stable@libav.org
Bug-Id: CID 1135739