On Sat, Nov 16, 2024 at 12:25:03PM +0100, Niklas Haas wrote: > From: Niklas Haas <g...@haasn.dev> > > This interface has been designed from the ground up to serve as a new > framework for dispatching various scaling operations at a high level. This > will eventually replace the old ad-hoc system of using cascaded contexts, > as well as allowing us to plug in more dynamic scaling passes requiring > intermediate steps, such as colorspace conversions, etc. > > The starter implementation merely piggybacks off the existing sws_init() and > sws_scale(), functions, though it does bring the immediate improvement of > splitting up cascaded functions and pre/post conversion functions into > separate filter passes, which allows them to e.g. be executed in parallel > even when the main scaler is required to be single threaded. Additionally, > a dedicated (multi-threaded) noop memcpy pass substantially improves > throughput of that fast path. > > Follow-up commits will eventually expand this to move all of the scaling > decision logic into the graph init function, and also eliminate some of the > current special cases. > > Sponsored-by: Sovereign Tech Fund > Signed-off-by: Niklas Haas <g...@haasn.dev> > --- > libswscale/Makefile | 1 + > libswscale/graph.c | 602 ++++++++++++++++++++++++++++++++++++++++++++ > libswscale/graph.h | 122 +++++++++ > 3 files changed, 725 insertions(+) > create mode 100644 libswscale/graph.c > create mode 100644 libswscale/graph.h > > diff --git a/libswscale/Makefile b/libswscale/Makefile > index 757997b401..81f32f4dd7 100644 > --- a/libswscale/Makefile > +++ b/libswscale/Makefile > @@ -9,6 +9,7 @@ OBJS = alphablend.o \ > hscale.o \ > hscale_fast_bilinear.o \ > gamma.o \ > + graph.o \ > half2float.o \ > input.o \ > options.o \ > diff --git a/libswscale/graph.c b/libswscale/graph.c > new file mode 100644 > index 0000000000..ec1015653e > --- /dev/null > +++ b/libswscale/graph.c > @@ -0,0 +1,602 @@ > +/* > + * Copyright (C) 2024 Niklas Haas > + * > + * This file is part of FFmpeg. > + * > + * FFmpeg is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * FFmpeg is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with FFmpeg; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 > USA > + */ > + > +#include "libavutil/avassert.h" > +#include "libavutil/error.h" > +#include "libavutil/macros.h" > +#include "libavutil/mem.h" > +#include "libavutil/opt.h" > +#include "libavutil/pixdesc.h" > +#include "libavutil/slicethread.h" > + > +#include "libswscale/swscale.h" > +#include "libswscale/utils.h" > + > +#include "swscale_internal.h" > +#include "graph.h" > +
> +/* slice_align should be a power of two, or 0 to disable slice threading */
/** for doxygen
unless its intentional
> +static SwsPass *pass_add(SwsGraph *graph, void *priv, int w, int h,
> + sws_filter_run_t run, SwsImg in, SwsImg out,
> + int slice_align)
> +{
> + SwsPass *pass = av_mallocz(sizeof(*pass));
> + int ret;
malloc failure check missing
[...]
> +static int vshift(enum AVPixelFormat fmt, int plane)
> +{
> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
> + const int is_pal = usePal(fmt);
> + const int is_chroma = (plane == 1 || plane == 2) && !is_pal;
gray + alpha ? (plane 1 would be alpha not chroma)
[...]
> +static void run_rgb0(const SwsImg *out, const SwsImg *in, int y, int h,
> + const SwsPass *pass)
> +{
> + SwsInternal *c = pass->priv;
> + const int x0 = c->src0Alpha - 1;
> + const int w4 = 4 * pass->width;
> + const int src_stride = in->linesize[0];
> + const int dst_stride = out->linesize[0];
> + const uint8_t *src = in->data[0] + y * src_stride;
> + uint8_t *dst = out->data[0] + y * dst_stride;
> +
> + for (int y = 0; y < h; y++) {
> + memcpy(dst, src, w4 * sizeof(*dst));
> + for (int x = x0; x < w4; x += 4)
> + dst[x] = 0xFF;
A loop reading 32 or 64 bit, setting FF and writing may be faster but maybe
this is the wrong time to suggest that
[...]
> diff --git a/libswscale/graph.h b/libswscale/graph.h
> new file mode 100644
> index 0000000000..8b4544973e
> --- /dev/null
> +++ b/libswscale/graph.h
> @@ -0,0 +1,122 @@
> +/*
> + * Copyright (C) 2024 Niklas Haas
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
> USA
> + */
> +
> +#ifndef SWSCALE_GRAPH_H
> +#define SWSCALE_GRAPH_H
> +
> +#include "libavutil/slicethread.h"
> +#include "swscale.h"
> +#include "utils.h"
> +
> +/* Represents a view into a single field of frame data */
> +typedef struct SwsImg {
> + enum AVPixelFormat fmt;
> + uint8_t *data[4]; /* points to y=0 */
> + int linesize[4];
> +} SwsImg;
> +
> +typedef struct SwsPass SwsPass;
> +typedef struct SwsGraph SwsGraph;
> +
> +/**
> + * Output `h` lines of filtered data. `out` and `in` point to the
> + * start of the image buffer for this pass.
> + */
> +typedef void (*sws_filter_run_t)(const SwsImg *out, const SwsImg *in,
> + int y, int h, const SwsPass *pass);
> +
> +struct SwsPass {
This should have some documentation
> + const SwsGraph *graph;
> + uint8_t *buf; /* temporary buffer for this pass, freed automatically */
> +
> + sws_filter_run_t run;
> + int width, height; /* new output size */
> + int pixel_bytes; /* bytes per pixel */
> + int slice_h; /* filter granularity */
> + int num_slices;
> +
> + /* Filter input/output. */
> + SwsImg input;
> + SwsImg output;
> +
> + /**
> + * Called once from the main thread before running the filter. Optional.
> + * `out` and `in` always point to the main image input/output, regardless
> + * of `input` and `output` fields.
> + */
> + void (*setup)(const SwsImg *out, const SwsImg *in, const SwsPass *pass);
this mixes doxygen compatible and incomplete comments
> +
> + void (*uninit)(const SwsPass *pass); /* optional */
> + void *priv;
> +};
> +
> +/* Filter graph, which represents a 'baked' pixel format conversion */
> +typedef struct SwsGraph {
> + SwsContext *ctx;
> + AVSliceThread *slicethread;
> + int num_threads; /* resolved at init() time */
> + int incomplete; /* set during init() if formats had to be inferred */
> + SwsContext *sws; /* wrapped legacy context */
> +
> + /* Sorted sequence of filter passes to apply */
> + SwsPass **passes;
> + int num_passes;
> +
> + /* Overall image parameters and flags */
> + SwsContext opts;
3 SwsContext, ctx, sws, opts. This is a little confusing, please docuemnt
this more verbosely
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato
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