Using one big table for the symbols and lengths makes it
possible to remove the pointers to the individual tables.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
After permuting both the codes, lengths and symbols tables so that
the codes tables are ordered from left to right in the tree, the codes
tables can be easily computed from the lengths tables at runtime and
therefore omitted. This saves about 2KB from the binary.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
When using ff_init_vlc_sparse() to create a VLC, three input tables are
used: A table for lengths, one for codes and one for symbols; the latter
one can be omitted, then a default one will be used. These input tables
will be traversed twice, once to get the long codes (which will be put
into subtables) and once for the small codes. The long codes are then
sorted so that entries that should be in the same subtable are
contiguous.
This commit adds an alternative to ff_init_vlc_sparse():
ff_init_vlc_from_lengths(). It is based upon the observation that if
lengths, codes and symbols tables are permuted (in the same way) so that
the codes are ordered from left to right in the corresponding tree and
if said tree is complete (i.e. every non-leaf node has two children),
the codes can be easily computed from the lengths and are therefore
redundant. This means that if one initializes such a VLC with explicitly
coded lengths, codes and symbols, the codes can be avoided; and even if
one has no explicitly coded symbols, it might still be beneficial to
remove the codes even when one has to add a new symbol table, because
codes are typically longer than symbols so that the latter often fit
into a smaller type, saving space.
Furthermore, given that the codes here are by definition ordered from
left to right, it is unnecessary to sort them again; for the same
reason, one does not have to traverse the input twice. This function
proved to be faster than ff_init_vlc_sparse() whenever it has been
benchmarked.
This function is usable for static tables (they can simply be permuted
once) as well as in scenarios where the tables are naturally ordered
from left to right in the tree; the latter e.g. happens with Smacker,
Theora and several other formats.
In order to make it also usable for (static) tables with incomplete trees,
negative lengths are used to indicate that there is an open end of a
certain length.
Finally, ff_init_vlc_from_lengths() has one downside compared to
ff_init_vlc_sparse(): The latter uses tables that can be reused by
encoders. Of course, one could calculate the needed table at runtime
if one so wishes, but it is nevertheless an obstacle.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Create a local one instead from a byte buffer input argument.
This prevents skipping bytes that may belong to another SEI message.
Signed-off-by: James Almer <jamrial@gmail.com>
The nvidia hardware explicitly supports decoding monochrome content,
presumably for the AVIF alpha channel. Supporting this requires an
adjustment in av1dec and explicit monochrome detection in nvdec.
I'm not sure why the monochrome path in av1dec did what it did - it
seems non-functional - YUV440P doesn't seem a logical pix_fmt for
monochrome and conditioning on chroma sub-sampling doesn't make sense.
So I changed it.
I've tested 8bit content, but I haven't found a way to create a 10bit
sample, so that path is untested for now.
Fixes: signed integer overflow: -2105540608 - 2105540608 cannot be represented in type 'int'
Fixes: 26870/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-5656647567147008
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
A reference to an AV1RawFrameHeader and consequently the
AV1RawFrameHeader itself and everything it has a reference to leak
if the hardware has no AV1 decoding capabilities or if some other error
happens. It happens e.g. in the cbs-av1-av1-1-b8-02-allintra FATE-test;
it has just been masked because the return value of ffmpeg (which
indicates failure when using Valgrind or ASAN) is ignored when doing
tests of type md5.
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This function existed to enable codecs with non-threadsafe init functions
to initialize other codecs despite the fact that normally no two codecs
with non-threadsafe init functions can be initialized at the same time
(there is a mutex guarding this). Yet there are no users of this
function any more as all users have been made thread-safe (switching
away from ff_codec_open2_recursive() was required for this as said
function requires the caller to hold the lock to the mutex guarding the
initializations and this is only true for codecs with the
FF_CODEC_CAP_INIT_THREADSAFE flag unset); so remove it.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
The only thing that stands in the way of adding the
FF_CODEC_CAP_INIT_THREADSAFE flag to the TIFF decoder is its usage
of ff_codec_open2_recursive(): This function requires its caller to hold
the lock for the mutex that guards initialization of AVCodecContexts
whose codecs have a non-threadsafe init function and only callers whose
codec does not have the FF_CODEC_CAP_INIT_THREADSAFE flag set hold said
lock (the others don't need to care about said lock). But one can set
the flag if one switches to avcodec_open2() at the same time.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This will allow to make the TIFF decoder's init function thread-safe.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
The only thing that stands in the way of adding the
FF_CODEC_CAP_INIT_THREADSAFE flag to the SMV JPEG decoder is its usage
of ff_codec_open2_recursive(): This function requires its caller to hold
the lock for the mutex that guards initialization of AVCodecContexts
whose codecs have a non-threadsafe init function and only callers whose
codec does not have the FF_CODEC_CAP_INIT_THREADSAFE flag set hold said
lock (the others don't need to care about said lock). But one can set
the flag if one switches to avcodec_open2() at the same time.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
The only thing that stands in the way of adding the
FF_CODEC_CAP_INIT_THREADSAFE flag to the Cintel RAW decoder is its usage
of ff_codec_open2_recursive(): This function requires its caller to hold
the lock for the mutex that guards initialization of AVCodecContexts
whose codecs have a non-threadsafe init function and only callers whose
codec does not have the FF_CODEC_CAP_INIT_THREADSAFE flag set hold said
lock (the others don't need to care about said lock). But one can set
the flag if one switches to avcodec_open2() at the same time.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Normally no two codecs with FF_CODEC_CAP_INIT_THREADSAFE unset
can be initialized at the same time: a mutex in avcodec_open2()
ensures this. This implies that one cannot simply open a codec
with a non-threadsafe init-function from the init function of
a codec whose own init function is not threadsafe either as the child
codec couldn't acquire the lock.
ff_codec_open2_recursive() exists to get around this limitation:
If the init function of the child codec to be initialized is not
thread-safe, the mutex is unlocked, the child is initialized and
the mutex is locked again. This of course has as a prerequisite that
the parent AVCodecContext actually holds the lock, i.e. that the
parent codec's init function is not thread-safe. If it is, then one
can (and has to) just use avcodec_open2() directly (if the child's
init function is not thread-safe, then avcodec_open2() will have to
acquire the mutex itself (and potentially wait for it), so that it is
perfectly fine for an otherwise thread-safe init function to open
a codec with a potentially non-thread-safe init function via
avcodec_open2()).
Yet several of the users of ff_codec_open2_recursive() have the
FF_CODEC_CAP_INIT_THREADSAFE flag set; this only worked because
all the child codecs' init functions were thread-safe themselves
so that ff_codec_open2_recursive() didn't touch the mutex at all.
But of course the real solution to this is to directly use
avcodec_open2().
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This affected all decoders that used ff_mjpeg_decode_init() as init
function; and it also affected decoders that open jpeg decoders via
ff_codec_open2_recursive() as well as MxPEG.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
