According to the WebP Lossless Bitstream Specification
"each transform is allowed to be used only once".
If a transform is more than once this can lead to memory
corruption.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit c089e720c1b753790c746a13053636d7facf6bf0)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
According to the WebP Lossless Bitstream Specification the highest
allowed value for a prefix code is 39.
If prefix_code is too large, the calculated extra_bits has an invalid
value and triggers an assertion in get_bits.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 5de2dab12b951b2fe121eb18503accfc91cd1565)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit e5b3112996c3da45aa03b39c5ade375d40d4407d)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
See https://code.google.com/p/webp/issues/detail?id=206
for a description of the problem/fix.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This patch makes the decoder follow the recommendation of the spec.
There is some disagreement (see "[FFmpeg-devel] [PATCH]: libavcodec/webp")
about what would be best to be written in the spec, so in case the spec
is changed again, this potentially would need to be amended or reverted
(cherry picked from commit 4fd21d58a72c38ab63c3a4483b420db260fa7b8d)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* commit 'c6698dfe7cdbc7634f33245875488ed3fa4a8ced':
webpdec: Fix decoding of the huffman group indices.
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Also remove "webp:" from log messages. Using the AVCodecContext is enough.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* commit 'f51e3a1971045c7ed0c3d9d29d3254a4d940198e':
webp: do not call av_frame_free() on the user-provided frame
Merged-by: Michael Niedermayer <michaelni@gmx.at>
The vlc reader cannot handle 0-bit huffman codes. For most
situations WebP uses the "simple" huffman coding for this case,
but that will only handle symbols up to 255. For the LZ77 distance
codes, larger symbol values are needed, so it can happen in rare
cases that a normal huffman table is used that only has a single
symbol.
* commit 'c4bfa098072ba338d83555d6e2199f7e1e64ffff':
Add a WebP decoder
Conflicts:
Changelog
doc/general.texi
libavcodec/Makefile
libavcodec/avcodec.h
libavcodec/version.h
libavformat/img2.c
The previously existing webp decoder is disabled as the new
one supports lossless mode and alpha while the previous does not.
Merged-by: Michael Niedermayer <michaelni@gmx.at>
