Previously these chunks where parsed again for each frame with threads
but not without leading to a different path and the potential for
inconsistencies
This also removes a related special case from decode_ihdr_chunk()
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Multiple IHDR chunks are forbidden in PNG
Fixes inconsistency and out of array accesses
Fixes: asan_heap-oob_4d5c5a_1738_cov_2638287726_c-m2-8f2b481b7fd9bd745e620b7c01a18df2.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Currently restricted to blending pixels that only contain either
0 or 255 in their alpha components
Signed-off-by: Donny Yang <work@kota.moe>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The spec specifies the dispose operation as how the current (i.e., currently
being rendered) frame should be disposed when the next frame is blended onto it
This is contrary to ffmpeg's current behaviour of interpreting the dispose
operation as how the previous (i.e., already rendered) frame should be disposed
This patch fixes ffmpeg's behaviour to match those of the spec, which involved
a rewrite of the blending function
Signed-off-by: Donny Yang <work@kota.moe>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ARGB is not a supported PNG pixel format
Signed-off-by: Donny Yang <work@kota.moe>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
AV_PIX_FMT_GRAY8/16 are considered YUV formats, and the color_range is
not set - so the API user will have to assume limitted range. (Unless
the API user adds a special-case for the PNG decoder.)
Just export the correct range - full range.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
AV_PIX_FMT_MONOBLACK has the AV_PIX_FMT_FLAG_BITSTREAM flag, i.e.
linesize can be smaller than width.
Since x_offset is only check against the width, this can lead to
x_offset * bpp >= image_linesize.
In this case ptr could be set to a position outside the image_buf in
png_handle_row, leading to memory corruption and thus crashes.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
During the loop ret can get changed. Since it is not set on all failure
paths, decode_frame_common can return 0 even though an error occurred.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This check was removed in commit 08aec6f6, but
s->last_picture.f->data[0] is still used in handle_p_frame_apng
unconditionally.
This fixes a segmentation fault.
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This fixes artifacts in the last pixel of rows with some widths and pixel formats
Found-by: Dominique Leroux <Dominique.Leroux@autodesk.com>
Tested-by: Dominique Leroux <Dominique.Leroux@autodesk.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Rely on the way memcpy is optimized for one's system instead of looping
on a byte buffer for buffer copies to handle P frames.
Tested-by: Christophe Gisquet <christophe.gisquet@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Use 'if (CONFIG_APNG_DECODER)' where needed, so that the compiler can
optimize out some portion of code.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
There is no need to memset the zlib output buffer, as there is no
blending happening there. Instead, do not blend when the dispose
operation is set to 'background' (tranparent black).
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Fixes out of array read
Fixes: asan_heap-oob_20b0a06_1962_cov_1907976991_delete_node_small.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Fixes out of array access
Fixes: asan_heap-oob_20a6c26_2690_cov_3434532168_mail.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Fixes out of array accesses
Fixes: asan_heap-oob_14dbfcf_4_asan_heap-oob_1ce5767_179_add_method_small.png
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The rationale is that you have a packed format in form
<greyscale sample> <alpha sample> <greyscale sample> <alpha sample>
and shortening greyscale to 'G' might make one thing about Greenscale instead.
An alias pixel format and color space name are provided for compatibility.
Donny Yang
Michael Niedermayer
wm4
Andreas Cadhalpun
Vittorio Giovara
Benoit Fouet