Improves the grepability of the code.
(Furthermore, I hope that no compiler will really call memset
for 28 bytes.)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
mpegvideo uses an array of Pictures and when it is done with using
them, it only unreferences them incompletely: Some buffers are kept
so that they can be reused lateron if the same slot in the Picture
array is reused, making this a sort of a bufferpool.
(Basically, a Picture is considered used if the AVFrame's buf is set.)
Yet given that other pieces of the decoder may have a reference to
these buffers, they need not be writable and are made writable using
av_buffer_make_writable() when preparing a new Picture. This involves
reading the buffer's data, although the old content of the buffer
need not be retained.
Worse, this read can be racy, because the buffer can be used by another
thread at the same time. This happens for Real Video 3 and 4.
This commit fixes this race by no longer copying the data;
instead the old buffer is replaced by a new, zero-allocated buffer.
(Here are the details of what happens with three or more decoding threads
when decoding rv30.rm from the FATE-suite as happens in the rv30 test:
The first decoding thread uses the first slot of its picture array
to store its current pic; update_thread_context copies this for the
second thread that decodes a P-frame. It uses the second slot in its
Picture array to store its P-frame. This arrangement is then copied
to the third decode thread, which decodes a B-frame. It uses the third
slot in its Picture array for its current frame.
update_thread_context copies this to the next thread. It unreferences
the third slot containing the other B-frame and then it reuses this
slot for its current frame. Because the pic array slots are only
incompletely unreferenced, the buffers of the previous B-frame are
still in there and they are not writable; in fact the previous
thread is concurrently writing to them, causing races when making
the buffer writable.)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
These fields are only ever set by the encoder for the current picture
and for no other picture. So only one set of these values needs to
exist, so move them to MpegEncContext.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Of all the buffers that are made writable, three are always allocated
and the other four are allocated iff any one of them is allocated;
so one can replace the seven checks for existence with one.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
These tables are only used by encoders and only for the current picture;
ergo they need not be put into the picture at all, but rather into
the encoder's context. They also don't need to be refcounted,
because there is only one owner.
In contrast to this, the earlier code refcounts them which
incurs unnecessary overhead. These references are not unreferenced
in ff_mpeg_unref_picture() (they are kept in order to have something
like a buffer pool), so that several buffers are kept at the same
time, although only one is needed, thereby wasting memory.
The code also propagates references to other pictures not part of
the pictures array (namely the copy of the current/next/last picture
in the MpegEncContext which get references of their own). These
references are not unreferenced in ff_mpeg_unref_picture() (the
buffers are probably kept in order to have something like a pool),
yet if the current picture is a B-frame, it gets unreferenced
at the end of ff_mpv_encode_picture() and its slot in the picture
array will therefore be reused the next time; but the copy of the
current picture also still has its references and therefore
these buffers will be made duplicated in order to make them writable
in the next call to ff_mpv_encode_picture(). This is of course
unnecessary.
Finally, ff_find_unused_picture() is supposed to just return
any unused picture and the code is supposed to work with it;
yet for the vsynth*-mpeg4-adap tests the result depends upon
the content of these buffers; given that this patchset
changes the content of these buffers (the initial content is now
the state of these buffers after encoding the last frame;
before this patch the buffers used came from the last picture
that occupied the same slot in the picture array) their ref-files
needed to be changed. This points to a bug somewhere (if one removes
the initialization, one gets uninitialized reads in
adaptive_quantization in ratecontrol.c).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Several encoders (roqvideo, svq1, snow, and the mpegvideo family)
currently call ff_get_buffer(). However this function is written
assuming it is called by a decoder. Though nothing has been obviously
broken by this until now, that may change in the future.
To avoid potential future issues, introduce a simple encode-specific
wrapper around avcodec_default_get_buffer2() and enforce its use in
encoders.
These will be used by the codecs that need allocated progress
and is in preparation for no longer using ThreadFrame by the codecs
that don't.
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Also use said function in mpegvideo.c and mpegvideo_enc.c;
and make ff_free_picture_tables() static as it isn't needed anymore
outside of mpegpicture.c.
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Do it only when requested with the AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS
flag.
Drop previous code using the long-deprecated AV_FRAME_DATA_QP_TABLE*
API. Temporarily disable fate-filter-pp, fate-filter-pp7,
fate-filter-spp. They will be reenabled once these filters are converted
in following commits.
Before adding uvlinesize check, I was seeing failures decoding
some video with ffmpeg compiled with --enable-gray and using AV_CODEC_FLAG_GRAY.
[mpeg2video @ 0x7fa193818c00] get_buffer() failed (stride changed: linesize=1280/1280 uvlinesize=0/640)
[mpeg2video @ 0x7fa193818c00] get_buffer() failed (stride changed: linesize=1280/1280 uvlinesize=0/640)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
In function ff_mpeg_ref_picture(), it returns 0 on the error path that
the return value of av_buffer_ref() is NULL. 0 indicates success, which
seems to deviate from the fact. Set ret to AVERROR(ENOMEM) to propagate
the error status to the callers.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
alloc_frame_buffer in ff_alloc_picture asserts that the linesize
of planes 1 and 2 are the same. If the pixfmt has a single uv
plane, like NV12, this won't be true.
So, let's only do this check if there are more than 2 planes.
We never hit this with previous hw formats because they don't set
linesize to meaningful values, but the cuda hw format sets the
values based on the underlying data layout.
These field are difficult to interpret, and are provided by a single
encoder (mpegvideoenc). In general they do not belong to a structure
containing raw data only, so remove them from AVFrame.
Mpegvideoenc now uses a private field in Picture for its internal
computations.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>