This function does not do any bitstream parsing and it depends on the
current frame being allocated, so this will allow the frame_start() to
be moved out eventually.
This will allow postponing the reference list construction (and by
consequence some other functions, like frame_start) until the whole
slice header has been parsed.
That function is currently very long and entangles bitstream parsing and
decoder configuration. This makes the code much harder to read than
necessary.
Begin splitting the code that configures the decoder state based on the
slice header information from the parsing of the slice header.
In such a case, decode the MBs in parallel without the loop filter, then
execute the filter serially.
The ref2frm array was previously moved to H264SliceContext. That was
incorrect, since it applies to all the slices and should properly be in
H264Context (it did not actually break decoding, since this distinction
only becomes relevant with slice threading and deblocking_filter=1,
which was not implemented before this commit). The ref2frm array is thus
moved back to H264Context.
It is always unconditionally initialized in decode_postinit() and then
immediately used in one place further below. All the other places where
it is accessed are just useless fluff.
Make the SPS/PPS parsing independent of the H264Context, to allow
decoupling the parser from the decoder. The change is modelled after the
one done earlier for HEVC.
Move the dequant buffers to the PPS to avoid complex checks whether they
changed and an expensive copy for frame threads.
Libav, for some reason, merged this as a public API function. This will
aid in future merges.
A define is left for backwards compat, just in case some person
used it, since it is in a public header.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
get_ue_golomb() cannot decode values larger than 8190 (the maximum
value that can be golomb encoded in 25 bits) and produces the error
"Invalid UE golomb code" if a larger value is encountered. Use
get_ue_golomb_long() instead (which supports 63 bits, up to 4294967294)
when valid h264/hevc values can exceed 8190.
This updates decoding of the following values: (maximum)
first_mb_in_slice 36863* for level 5.2
abs_diff_pic_num_minus1 131071
difference_of_pic_nums_minus1 131071
idr_pic_id 65535
recovery_frame_cnt 65535
frame_packing_arrangement_id 4294967294
frame_packing_arrangement_repetition_period 16384
display_orientation_repetition_period 16384
An alternative would be to modify get_ue_golomb() to handle encoded
values of up to 49 bits as was done for get_se_golomb() in a92816c.
In that case get_ue_golomb() could continue to be used for all of
these except frame_packing_arrangement_id.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
According to the spec, the reference list for a slice should be
constructed by first generating an initial (what we now call "default")
reference list and then optionally applying modifications to it.
Our code has an optimization where the initial reference list is
constructed for the first inter slice and then rebuilt for other slices
if needed. This, however, adds complexity to the code, requires an extra
2.5kB array in the codec context and there is no reason to think that it
has any positive effect on performance. Therefore, simplify the code by
generating the reference list from scratch for each slice.
Fixes out of array access
Fixes: 1430e9c43fae47a24c179c7c54f94918/signal_sigsegv_421427_2049_f2192b6829ab6e0eefcb035329c03c60.264
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
In case of bitstream errors the deblock filter and slices can access uninitialized
top_borders from previous slices which did not fill them as they stoped halfway due
to error or where entirely missing.
This also makes code using these tables deterministic in case of missing or damaged
slices
Found-by: Tyson Smith
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
It is only used inside libavcodec.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Anton Khirnov
Vittorio Giovara
Diego Biurrun
Michael Niedermayer
Mark Thompson
Derek Buitenhuis
Mark Harris
Andreas Cadhalpun
wm4