lavfi: add hue filter

This is a port of the MPlayer hue filter (libmpcodecs/vf_hue.c) by
Michael Niedermayer.

Signed-off-by: Jérémy Tran <tran.jeremy.av@gmail.com>
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

Changelog

@@ -44,6 +44,7 @@ version next:
 - bmp parser
 - smptebars source
 - asetpts filter
+- hue filter
 
 
 version 0.11:

doc/filters.texi

@@ -2187,6 +2187,17 @@ a float number which specifies chroma temporal strength, defaults to
 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
 @end table
 
+@section hue
+
+Modify the hue and/or the saturation of the input.
+
+This filter accepts the optional parameters: @var{hue}:@var{saturation}.
+
+@var{hue} must be a float number that specifies the hue angle as a
+number of degrees, and defaults to 0.0.
+@var{saturation} must be a float number that specifies the saturation
+in the [-10,10] range, and defaults to 1.0.
+
 @section idet
 
 Interlaceing detect filter. This filter tries to detect if the input is

libavfilter/Makefile

@@ -99,6 +99,7 @@ OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o
 OBJS-$(CONFIG_GRADFUN_FILTER)                += vf_gradfun.o
 OBJS-$(CONFIG_HFLIP_FILTER)                  += vf_hflip.o
 OBJS-$(CONFIG_HQDN3D_FILTER)                 += vf_hqdn3d.o
+OBJS-$(CONFIG_HUE_FILTER)                    += vf_hue.o
 OBJS-$(CONFIG_IDET_FILTER)                   += vf_idet.o
 OBJS-$(CONFIG_LUT_FILTER)                    += vf_lut.o
 OBJS-$(CONFIG_LUTRGB_FILTER)                 += vf_lut.o

libavfilter/allfilters.c

@@ -89,6 +89,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (GRADFUN,     gradfun,     vf);
     REGISTER_FILTER (HFLIP,       hflip,       vf);
     REGISTER_FILTER (HQDN3D,      hqdn3d,      vf);
+    REGISTER_FILTER (HUE,         hue,         vf);
     REGISTER_FILTER (IDET,        idet,        vf);
     REGISTER_FILTER (LUT,         lut,         vf);
     REGISTER_FILTER (LUTRGB,      lutrgb,      vf);

libavfilter/version.h

@@ -29,7 +29,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  8
+#define LIBAVFILTER_VERSION_MINOR  9
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_hue.c

@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2003 Michael Niedermayer
+ * Copyright (c) 2012 Jeremy Tran
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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.
+ */
+
+/**
+ * @file
+ * Apply a hue/saturation filter to the input video
+ * Ported from MPlayer libmpcodecs/vf_hue.c.
+ */
+
+#include "libavutil/imgutils.h"
+#include "libavutil/pixdesc.h"
+
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct {
+    float    hue;
+    float    saturation;
+    int      hsub;
+    int      vsub;
+    int32_t hue_sin;
+    int32_t hue_cos;
+} HueContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args)
+{
+    HueContext *hue = ctx->priv;
+    float h = 0, s = 1;
+    int n;
+    char c1 = 0, c2 = 0;
+
+    if (args) {
+        n = sscanf(args, "%f%c%f%c", &h, &c1, &s, &c2);
+        if (n != 0 && n != 1 && (n != 3 || c1 != ':')) {
+            av_log(ctx, AV_LOG_ERROR,
+                   "Invalid syntax for argument '%s': "
+                   "must be in the form 'hue[:saturation]'\n", args);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    if (s < -10 || s > 10) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Invalid value for saturation %0.1f: "
+               "must be included between range -10 and +10\n", s);
+        return AVERROR(EINVAL);
+    }
+
+    /* Convert angle from degree to radian */
+    hue->hue = h * M_PI / 180;
+    hue->saturation = s;
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum PixelFormat pix_fmts[] = {
+        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
+        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
+        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
+        PIX_FMT_YUVA420P,
+        PIX_FMT_NONE
+    };
+
+    ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+
+    return 0;
+}
+
+static int config_props(AVFilterLink *inlink)
+{
+    HueContext *hue = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[inlink->format];
+
+    hue->hsub = desc->log2_chroma_w;
+    hue->vsub = desc->log2_chroma_h;
+    /*
+     * Scale the value to the norm of the resulting (U,V) vector, that is
+     * the saturation.
+     * This will be useful in the process_chrominance function.
+     */
+    hue->hue_sin = rint(sin(hue->hue) * (1 << 16) * hue->saturation);
+    hue->hue_cos = rint(cos(hue->hue) * (1 << 16) * hue->saturation);
+
+    return 0;
+}
+
+static void process_chrominance(uint8_t *udst, uint8_t *vdst, const int dst_linesize,
+                                uint8_t *usrc, uint8_t *vsrc, const int src_linesize,
+                                int w, int h,
+                                const int32_t c, const int32_t s)
+{
+    int32_t u, v, new_u, new_v;
+    int i;
+
+    /*
+     * If we consider U and V as the components of a 2D vector then its angle
+     * is the hue and the norm is the saturation
+     */
+    while (h--) {
+        for (i = 0; i < w; i++) {
+            /* Normalize the components from range [16;140] to [-112;112] */
+            u = usrc[i] - 128;
+            v = vsrc[i] - 128;
+            /*
+             * Apply the rotation of the vector : (c * u) - (s * v)
+             *                                    (s * u) + (c * v)
+             * De-normalize the components (without forgetting to scale 128
+             * by << 16)
+             * Finally scale back the result by >> 16
+             */
+            new_u = ((c * u) - (s * v) + (1 << 15) + (128 << 16)) >> 16;
+            new_v = ((s * u) + (c * v) + (1 << 15) + (128 << 16)) >> 16;
+
+            /* Prevent a potential overflow */
+            udst[i] = av_clip_uint8_c(new_u);
+            vdst[i] = av_clip_uint8_c(new_v);
+        }
+
+        usrc += src_linesize;
+        vsrc += src_linesize;
+        udst += dst_linesize;
+        vdst += dst_linesize;
+    }
+}
+
+static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+    HueContext        *hue    = inlink->dst->priv;
+    AVFilterBufferRef *inpic  = inlink->cur_buf;
+    AVFilterBufferRef *outpic = inlink->dst->outputs[0]->out_buf;
+    uint8_t *inrow[3], *outrow[3]; // 0 : Y, 1 : U, 2 : V
+    int plane;
+
+    inrow[0]  = inpic->data[0]  + y * inpic->linesize[0];
+    outrow[0] = outpic->data[0] + y * outpic->linesize[0];
+
+    for (plane = 1; plane < 3; plane++) {
+        inrow[plane]  = inpic->data[plane]  + (y >> hue->vsub) * inpic->linesize[plane];
+        outrow[plane] = outpic->data[plane] + (y >> hue->vsub) * outpic->linesize[plane];
+    }
+
+    av_image_copy_plane(outrow[0], outpic->linesize[0],
+                        inrow[0],  inpic->linesize[0],
+                        inlink->w, inlink->h);
+
+    process_chrominance(outrow[1], outrow[2], outpic->linesize[1],
+                        inrow[1], inrow[2], inpic->linesize[1],
+                        inlink->w >> hue->hsub, inlink->h >> hue->vsub,
+                        hue->hue_cos, hue->hue_sin);
+
+    return ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
+}
+
+AVFilter avfilter_vf_hue = {
+    .name        = "hue",
+    .description = NULL_IF_CONFIG_SMALL("Adjust the hue and saturation of the input video."),
+
+    .priv_size = sizeof(HueContext),
+
+    .init          = init,
+    .query_formats = query_formats,
+
+    .inputs = (const AVFilterPad[]) {
+        {
+            .name         = "default",
+            .type         = AVMEDIA_TYPE_VIDEO,
+            .draw_slice   = draw_slice,
+            .config_props = config_props,
+            .min_perms    = AV_PERM_READ,
+        },
+        { .name = NULL }
+    },
+    .outputs = (const AVFilterPad[]) {
+        {
+            .name         = "default",
+            .type         = AVMEDIA_TYPE_VIDEO,
+        },
+        { .name = NULL }
+    }
+};