Because we need access to ref frames without film grain applied, we have
to add an extra AVFrame to H264Picture to avoid messing with the
original. This requires some amount of overhead to make the reference
moves work out, but it allows us to benefit from frame multithreading
for film grain application "for free".
Unfortunately, this approach requires twice as much RAM to be constantly
allocated for ref frames, due to the need for an extra buffer per
H264Picture. In theory, we could get away with freeing up this memory as
soon as it's no longer needed (since ref frames do not need film grain
buffers any longer), but trying to call ff_thread_release_buffer() from
output_frame() conflicts with possible later accesses to that same frame
and I'm not sure how to synchronize that well.
Tested on all three cases of (no fg), (fg present but exported) and (fg
present and not exported), with and without threading.
Co-authored-by: James Almer <jamrial@gmail.com>
Signed-off-by: Niklas Haas <git@haasn.dev>
Signed-off-by: James Almer <jamrial@gmail.com>
From SMPTE RDD 5-2006, the grain seed is to be computed from the
following definition of `pic_offset`:
> When decoding H.264 | MPEG-4 AVC bitstreams, pic_offset is defined as
> follows:
> - pic_offset = PicOrderCnt(CurrPic) + (PicOrderCnt_offset << 5)
> where:
> - PicOrderCnt(CurrPic) is the picture order count of the current frame,
> which shall be derived from [the video stream].
>
> - PicOrderCnt_offset is set to idr_pic_id on IDR frames. idr_pic_id
> shall be read from the slice header of [the video stream]. On non-IDR I
> frames, PicOrderCnt_offset is set to 0. A frame shall be classified as I
> frame when all its slices are I slices, which may be optionally
> designated by setting primary_pic_type to 0 in the access delimiter NAL
> unit. Otherwise, PicOrderCnt_offset it not changed. PicOrderCnt_offset is
> updated in decoding order.
Co-authored-by: James Almer <jamrial@gmail.com>
Signed-off-by: Niklas Haas <git@haasn.dev>
Signed-off-by: James Almer <jamrial@gmail.com>
Will remove unnecessary allocations when both src and dst picture contain
references to the same buffers.
Signed-off-by: James Almer <jamrial@gmail.com>
Once removed in 4a9bab3db0.
Introduced again in b25cd7540e.
Signed-off-by: Linjie Fu <fulinjie@zju.edu.cn>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Do not use the one in the SEI directly as that is reset at certain
points.
Inspired by patches from Michael Niedermayer <michaelni@gmx.at> and
Anton Mitrofanov <BugMaster@narod.ru>.
CC: libav-stable@libav.org
This merges commit 4fded0480f from libav,
originally written by Anton Khirnov and skipped in
fc63d5ceb3.
libavcodec/h264_slice.c | 20 +++++++++++++-------
libavcodec/h264dec.c | 3 +++
libavcodec/h264dec.h | 5 +++++
3 files changed, 21 insertions(+), 7 deletions(-)
This treats the case of no slices like no frames which it basically is.
The field is added to the context as other nal related fields are also there
and passing the has_slices field per *arguments is ugly and not consistent
Found-by: ubitux
Approved-by: ubitux
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
The current condition can trigger in cases where it shouldn't, with
unexpected results.
Make sure that:
- container cropping is really based on the original dimensions from the
caller
- those dimenions are discarded on size change
The code is still quite hacky and eventually should be deprecated and
removed, with the decision about which cropping is used delegated to the
caller.
Calling ff_h264_field_end() when the per-field state is not properly
initialized leads to all kinds of undefined behaviour.
CC: libav-stable@libav.org
Bug-Id: 977 978 992
The parser changes have lost the support for the needed padding, this adds it back
Fixes out of array reads
Fixes: 03ea21d271abc8acf428d42ace51d8b4/asan_heap-oob_3358eef_5692_16f0cc01ab5225e9ce591659e5c20e35.mkv
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Since we only know whether a NAL unit corresponds to a new field after
parsing the slice header, this requires reorganizing the calls to slice
parsing, per-slice/field/frame init and actual decoding.
In the previous code, the function for slice header decoding also
immediately started a new field/frame as necessary, so any slices
already queued for decoding would no longer be decodable.
After this patch, we first parse the slice header, and if we determine
that a new field needs to be started we decode all the queued slices.
This function's purpose is not very well defined. Currently it does two
(only marginally related) things: selecting the next output frame and
calling ff_thread_finish_setup() for frame threading. The first of those
more properly belongs under field_start(), while the second can be
called directly from decode_nal_units().
Move the NAL unit types into it. This will allow to stop including the
whole decoder-specific h264dec.h in some code that is unrelated to the
decoder and only needs some enum values.
While the value of those variables will be constant for the whole frame,
they are only used in two functions called from slice header decoding.
Moving them to the per-slice context allows us to make the H264Context
passed to slice_header_parse() constant.
Replace the decoder-global nal_unit_type/nal_ref_idc variables with the
per-NAL ones. The decoder-global ones still cannot be removed because
they are used by hwaccels.
Do it right before the MMCOs are applied to the DPB. This will allow
moving the frame_start() call out of the slice header parsing, since
generating the implicit MMCOs needs to be done after frame_start().
They are stored in the slice header, so technically they are per-slice
(though they must be the same in every slice). This will simplify the
following commits.
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.
Niklas Haas
James Almer
Anton Khirnov
Linjie Fu
Michael Niedermayer
Ronald S. Bultje
Timothy Gu
Matthieu Bouron
Clément Bœsch
Vittorio Giovara