[FFmpeg-devel] rectification filter

Daniel Oberhoff danieloberhoff at gmail.com
Tue Jul 29 00:34:52 CEST 2014


Hi again,

Since at least in the web view of the list attachements seem to be stripped, I send it here in the clear:

thanks for reviewing!

Daniel

From 7b5b3b42804714ddc56d2b8cd2c5709b4bb91f70 Mon Sep 17 00:00:00 2001
From: Daniel Oberhoff <daniel at danieloberhoff.de>
Date: Mon, 28 Jul 2014 23:58:12 +0200
Subject: [PATCH] added rectification filter

---
 libavfilter/Makefile           |   1 +
 libavfilter/allfilters.c       |   1 +
 libavfilter/vf_rectification.c | 277 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 279 insertions(+)
 create mode 100644 libavfilter/vf_rectification.c

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 0f54381..1488eae 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -199,6 +199,7 @@ OBJS-$(CONFIG_W3FDIF_FILTER)                 += vf_w3fdif.o
 OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
 OBJS-$(CONFIG_ZMQ_FILTER)                    += f_zmq.o
 OBJS-$(CONFIG_ZOOMPAN_FILTER)                += vf_zoompan.o
+OBJS-$(CONFIG_RECTIFICATION_FILTER)          += vf_rectification.o
 
 OBJS-$(CONFIG_CELLAUTO_FILTER)               += vsrc_cellauto.o
 OBJS-$(CONFIG_COLOR_FILTER)                  += vsrc_testsrc.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 1877557..f6e7bc2 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -216,6 +216,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(YADIF,          yadif,          vf);
     REGISTER_FILTER(ZMQ,            zmq,            vf);
     REGISTER_FILTER(ZOOMPAN,        zoompan,        vf);
+    REGISTER_FILTER(RECTIFICATION,  rectification,  vf);
 
     REGISTER_FILTER(CELLAUTO,       cellauto,       vsrc);
     REGISTER_FILTER(COLOR,          color,          vsrc);
diff --git a/libavfilter/vf_rectification.c b/libavfilter/vf_rectification.c
new file mode 100644
index 0000000..fda4ebd
--- /dev/null
+++ b/libavfilter/vf_rectification.c
@@ -0,0 +1,277 @@
+/* rectification.c
+ * Copyright (C) 2007 Richard Spindler
+ * This file is a Frei0r plugin.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdlib.h>
+#include <math.h>
+#include <assert.h>
+#include <time.h>
+#include <stdio.h>
+#include <string.h>
+
+// todo: use ffmpeg's configure, or available results thereof, to decide this
+//       using vectorization is definitely noticeable, but maybe due only to loop unrolling...
+#define HAVE_M512 0
+#define HAVE_M256 0
+#define HAVE_M128 1
+
+// todo: only include what's needed for the given vector width
+#include <emmintrin.h>
+#include <immintrin.h>
+#include <pmmintrin.h>
+#include <x86intrin.h>
+
+#if HAVE_M512
+    typedef __m512 VectorValue;
+#   define VECTOR_SIZE 16
+#   define SET1(x) _mm512_set1_ps(x)
+#elif HAVE_M256
+    typedef __m256 VectorValue;
+#   define SET1(x) _mm256_set1_ps(x)
+#   define VECTOR_SIZE 8
+#elif HAVE_M128
+    typedef __m128 VectorValue;
+#   define SET1(x) _mm_set1_ps(x)
+#   define VECTOR_SIZE 4
+#else
+    typedef float VectorValue;
+#   define VECTOR_SIZE 1
+#   define SET1(x) x
+#endif
+
+#include "libavutil/opt.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/pixdesc.h"
+
+#include "avfilter.h"
+#include "drawutils.h"
+#include "internal.h"
+#include "video.h"
+
+#include <float.h>
+
+typedef struct RectificationCtx
+{
+  AVClass* av_class;
+  unsigned int width;
+  unsigned int height;
+  int hsub, vsub;
+  int nb_planes;
+  FFDrawContext draw;
+  double cx, cy, k1, k2;
+} RectificationCtx;
+
+VectorValue make_spread(float x, float delta);
+
+VectorValue make_spread(float x, float delta)
+{
+    VectorValue result;
+    float* p = (float*)&result; 
+    for (size_t i = 0; i < VECTOR_SIZE; ++i, x += delta)
+    {
+        p[i] = x;
+    }
+    return result;
+}
+
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+static const AVOption rectification_options[] = {
+    { "cx",     "set relative center x", offsetof(RectificationCtx, cx), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
+    { "cy",     "set relative center y", offsetof(RectificationCtx, cy), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
+    { "k1",     "set quadratic distortion factor", offsetof(RectificationCtx, k1), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
+    { "k2",     "set double quadratic distortion factor", offsetof(RectificationCtx, k2), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(rectification);
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+}
+
+typedef struct ThreadData
+{
+    AVFrame *in, *out;
+    int w, h;
+    int plane;
+    float xcenter, ycenter;
+    float k1, k2;
+}ThreadData;
+
+static int filter_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
+{
+    ThreadData* td = (ThreadData*)arg;
+    RectificationCtx* rect = (RectificationCtx*)ctx->priv;
+
+    typedef float Scalar;
+
+    AVFrame *in = td->in;
+    AVFrame *out = td->out;
+
+    // pre-calc values needed in the loop
+    const int w = td->w, h = td->h;
+    const Scalar xcenter = td->xcenter;
+    const Scalar ycenter = td->ycenter;
+    const Scalar normallise_radius_sq = 4.0 / (w * w + h * h);
+    const VectorValue k1 = SET1(td->k1 - 0.5);
+    const VectorValue k2 = SET1(td->k2 - 0.5);
+    const VectorValue one = SET1(1);
+    const int start = (h *  job   ) / nb_jobs;
+    const int end   = (h * (job+1)) / nb_jobs;
+    const int plane = td->plane;
+    const int inlinesize = in->linesize[plane];
+    const int outlinesize = out->linesize[plane];
+    const uint8_t* indata = in->data[plane];
+    uint8_t* outrow = out->data[plane] + start * outlinesize;
+    for(int i = start; i < end; ++i, outrow += outlinesize) 
+    {
+        Scalar off_y = i - ycenter;
+        const Scalar off_y2 = off_y * off_y;
+        VectorValue off_x = make_spread(-xcenter, 1);
+        uint8_t* out = outrow;
+        for(int j = 0; j < w; j += VECTOR_SIZE, off_x += SET1(VECTOR_SIZE), out += VECTOR_SIZE)
+        {
+            const VectorValue r2 = (off_x * off_x + SET1(off_y2)) * SET1(normallise_radius_sq);
+            const VectorValue radius_mult = one + r2 * k1 + r2 * r2 * k2;
+            const VectorValue srcX = SET1(xcenter) + radius_mult * off_x;
+            const VectorValue srcY = SET1(ycenter) + radius_mult * SET1(off_y);
+            const Scalar* X = (const Scalar*)&srcX;
+            const Scalar* Y = (const Scalar*)&srcY;
+#define DOPIXEL(i) {const int x = X[i] + 0.5f, y = Y[i] + 0.5f; const char isvalid = (x > 0 && x < w - 1 && y > 0 && y < h - 1); out[i] =  isvalid ? indata[y * inlinesize + x] : 0;}
+#ifdef HAVE_M256
+            DOPIXEL(0);
+            DOPIXEL(1);
+            DOPIXEL(2);
+            DOPIXEL(3);
+            DOPIXEL(4);
+            DOPIXEL(5);
+            DOPIXEL(6);
+            DOPIXEL(7);
+#elif defined(HAVE_M128)
+            DOPIXEL(0);
+            DOPIXEL(1);
+            DOPIXEL(2);
+            DOPIXEL(3);
+#else
+            for (size_t i = 0; i < VECTOR_SIZE; ++i)
+            {
+                DOPIXEL(i);
+            }
+#endif
+#undef DOPIXEL
+        }        
+    }
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static enum PixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV410P,
+        AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUVJ420P,
+        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA420P,
+        AV_PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+    return 0;
+}
+
+static int config_props(AVFilterLink *outlink)
+{
+    AVFilterContext*  ctx = outlink->src;
+    RectificationCtx* rect = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
+    ff_draw_init(&rect->draw, inlink->format, 0);
+    rect->hsub = pixdesc->log2_chroma_w;
+    rect->vsub = pixdesc->log2_chroma_h;
+    outlink->w = rect->width = inlink->w;
+    outlink->h = rect->height = inlink->h;
+    rect->nb_planes = av_pix_fmt_count_planes(inlink->format);
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    RectificationCtx* rect = (RectificationCtx*)ctx->priv;
+    AVFrame* out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+    for (int plane = 0; plane < rect->nb_planes; ++plane) {
+        int hsub = plane == 1 || plane == 2 ? rect->hsub : 0;
+        int vsub = plane == 1 || plane == 2 ? rect->vsub : 0;
+        const int w = rect->width >> hsub;
+        const int h = rect->height >> vsub;
+        ThreadData td = { .in = in,   .out  = out,
+                          .w  = w,
+                          .h  = h,
+                          .xcenter = rect->cx * w,
+                          .ycenter = rect->cy * h,
+                          .k1 = rect->k1,
+                          .k2 = rect->k2,
+                          .plane = plane};
+        ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(h, ctx->graph->nb_threads));
+    }
+
+    av_frame_free(&in);
+    return ff_filter_frame(outlink, out);
+}
+
+static const AVFilterPad rectification_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad rectification_outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_props,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_rectification = {
+    .name          = "rectification",
+    .description   = NULL_IF_CONFIG_SMALL("rectify the image."),
+    .priv_size     = sizeof(RectificationCtx),
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .process_command = NULL,
+    .inputs        = rectification_inputs,
+    .outputs       = rectification_outputs,
+    .priv_class    = &rectification_class,
+    .flags         = AVFILTER_FLAG_SLICE_THREADS,
+};
\ No newline at end of file
-- 
1.8.2



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