Avoids len from becoming negative and causing assertion failure

Fixes: signal_sigabrt_7ffff7126425_5140_fd44dc63fa7bdd12ee34fc602231ef02.jpg

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixes integer overflow and assertion failure
Fixes: signal_sigabrt_7ffff7126425_1243_CASSE.HNM

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Its possible in various rare cases that an index cannot be created or allocated.
Fixes assertion failure
Fixes: signal_sigabrt_7ffff7126425_7712_pokem.avi

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Nitted-By: ubitux

This should fix trac tickets #1163, #2502.

This allows to make use of validation features.

In particular, document AV_DICT_MATCH_CASE, AV_DICT_IGNORE_SUFFIX, and
extend documentation for av_dict_get().

* qatar/master:
  aacps: Adjust some const qualifiers to suppress warnings
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '430d1219':
  pcx: round up in bits->bytes conversion in a buffer size check

Conflicts:
	libavcodec/pcx.c

See: 6462268eMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'c918e08b':
  truemotion1: make sure index does not go out of bounds

See: fd4c1c0bMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'ce9bba53':
  avidec: fix a memleak in the dv init code.

Conflicts:
	libavformat/avidec.c

See: 8993c256Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'de4ec972':
  vc1: fix a memleak.

Conflicts:
	libavcodec/vc1dec.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'ca41c72c':
  motionpixels: clip VLC codes.

Not merged, the change is wrong, the condition is not possible unless
there are serious bugs elsewhere. No such bugs should exist in ffmpeg.
Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '8b516f15':
  matroskadec: use correct compression parameters for current track CodecPrivate

See: dc6c36ceMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '30be1ea3':
  matroskadec: pad EBML_BIN data.

Conflicts:
	libavformat/matroskadec.c

See: c63e76baMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'f0259a58':
  h264: check buffer size before accessing it

Conflicts:
	libavcodec/h264.c

See: ea0ac11eMerged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '1f3e56b6':
  gifdec: convert to bytestream2

Conflicts:
	libavcodec/gifdec.c
	libavcodec/lzw.c
	libavcodec/lzw.h

See: 3fd60d80Merged-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

* commit 'c453723a':
  gifdec: check that the image dimensions are non-zero

Conflicts:
	libavcodec/gifdec.c

See: 286930d3Merged-by: Michael Niedermayer <michaelni@gmx.at>

* commit '074c769d':
  h264_cavlc: check the size of the intra PCM data.

This check is redundant, but does no harm
Merged-by: Michael Niedermayer <michaelni@gmx.at>

Fixes Ticket3119
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

(cherry picked from commit 0c8dfd8ad6400b33da55a9f4d9aa8d3f5c9d209f)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

(cherry picked from commit 088f2eb1ae42bffc63c2cee4e7eba8f47056043b)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

avcodec_close() does nothing in case the argument is NULL. Simplify.

Fix crash in case of expression parsing failure.

hevc : update hls_decode_neighbour(cherry picked from commit 14341c6d9a6885657ba365807223e96a67d6c0ed)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Fixes invalid reads.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org

Fixes invalid reads.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC:libav-stable@libav.org

Happens on a B-frame when neither low_delay nor last_picture_ptr is set
(probably corrupted streams only).

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind