lavfi/hue: allow changing brightness

Signed-off-by: Paul B Mahol <onemda@gmail.com>

doc/filters.texi

@@ -4715,12 +4715,16 @@ defaults to "1".
 @item H
 Specify the hue angle as a number of radians. It accepts an
 expression, and defaults to "0".
+
+@item b
+Specify the brightness in the [-10,10] range. It accepts an expression and
+defaults to "0".
 @end table
 
 @option{h} and @option{H} are mutually exclusive, and can't be
 specified at the same time.
 
-The @option{h}, @option{H} and @option{s} option values are
+The @option{b}, @option{h}, @option{H} and @option{s} option values are
 expressions containing the following constants:
 
 @table @option
@@ -4790,10 +4794,11 @@ hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
 
 This filter supports the following commands:
 @table @option
+@item b
 @item s
 @item h
 @item H
-Modify the hue and/or the saturation of the input video.
+Modify the hue and/or the saturation and/or brightness of the input video.
 The command accepts the same syntax of the corresponding option.
 
 If the specified expression is not valid, it is kept at its current

libavfilter/version.h

@@ -31,7 +31,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR  3
 #define LIBAVFILTER_VERSION_MINOR  82
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

libavfilter/vf_hue.c

@@ -68,11 +68,15 @@ typedef struct {
     float    saturation;
     char     *saturation_expr;
     AVExpr   *saturation_pexpr;
+    float    brightness;
+    char     *brightness_expr;
+    AVExpr   *brightness_pexpr;
     int      hsub;
     int      vsub;
     int32_t hue_sin;
     int32_t hue_cos;
     double   var_values[VAR_NB];
+    uint8_t  lut_l[256];
     uint8_t  lut_u[256][256];
     uint8_t  lut_v[256][256];
 } HueContext;
@@ -86,6 +90,8 @@ static const AVOption hue_options[] = {
       { .str = "1" }, .flags = FLAGS },
     { "H", "set the hue angle radians expression", OFFSET(hue_expr), AV_OPT_TYPE_STRING,
       { .str = NULL }, .flags = FLAGS },
+    { "b", "set the brightness expression", OFFSET(brightness_expr), AV_OPT_TYPE_STRING,
+      { .str = "0" }, .flags = FLAGS },
     { NULL }
 };
 
@@ -102,6 +108,16 @@ static inline void compute_sin_and_cos(HueContext *hue)
     hue->hue_cos = rint(cos(hue->hue) * (1 << 16) * hue->saturation);
 }
 
+static inline void create_luma_lut(HueContext *h)
+{
+    const float b = h->brightness;
+    int i;
+
+    for (i = 0; i < 256; i++) {
+        h->lut_l[i] = av_clip_uint8(i + b * 25.5);
+    }
+}
+
 static inline void create_chrominance_lut(HueContext *h, const int32_t c,
                                           const int32_t s)
 {
@@ -181,14 +197,15 @@ static av_cold int init(AVFilterContext *ctx)
         if (ret < 0)                                                    \
             return ret;                                                 \
     } while (0)
+    SET_EXPR(brightness, "b");
     SET_EXPR(saturation, "s");
     SET_EXPR(hue_deg,    "h");
     SET_EXPR(hue,        "H");
 #undef SET_EXPR
 
     av_log(ctx, AV_LOG_VERBOSE,
-           "H_expr:%s h_deg_expr:%s s_expr:%s\n",
-           hue->hue_expr, hue->hue_deg_expr, hue->saturation_expr);
+           "H_expr:%s h_deg_expr:%s s_expr:%s b_expr:%s\n",
+           hue->hue_expr, hue->hue_deg_expr, hue->saturation_expr, hue->brightness_expr);
     compute_sin_and_cos(hue);
 
     return 0;
@@ -198,6 +215,7 @@ static av_cold void uninit(AVFilterContext *ctx)
 {
     HueContext *hue = ctx->priv;
 
+    av_expr_free(hue->brightness_pexpr);
     av_expr_free(hue->hue_deg_pexpr);
     av_expr_free(hue->hue_pexpr);
     av_expr_free(hue->saturation_pexpr);
@@ -235,6 +253,22 @@ static int config_props(AVFilterLink *inlink)
     return 0;
 }
 
+static void apply_luma_lut(HueContext *s,
+                           uint8_t *ldst, const int dst_linesize,
+                           uint8_t *lsrc, const int src_linesize,
+                           int w, int h)
+{
+    int i;
+
+    while (h--) {
+        for (i = 0; i < w; i++)
+            ldst[i] = s->lut_l[lsrc[i]];
+
+        lsrc += src_linesize;
+        ldst += dst_linesize;
+    }
+}
+
 static void apply_lut(HueContext *s,
                       uint8_t *udst, uint8_t *vdst, const int dst_linesize,
                       uint8_t *usrc, uint8_t *vsrc, const int src_linesize,
@@ -267,6 +301,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)
     AVFilterLink *outlink = inlink->dst->outputs[0];
     AVFrame *outpic;
     const int32_t old_hue_sin = hue->hue_sin, old_hue_cos = hue->hue_cos;
+    const float old_brightness = hue->brightness;
     int direct = 0;
 
     if (av_frame_is_writable(inpic)) {
@@ -296,6 +331,17 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)
         }
     }
 
+    if (hue->brightness_expr) {
+        hue->brightness = av_expr_eval(hue->brightness_pexpr, hue->var_values, NULL);
+
+        if (hue->brightness < -10 || hue->brightness > 10) {
+            hue->brightness = av_clipf(hue->brightness, -10, 10);
+            av_log(inlink->dst, AV_LOG_WARNING,
+                   "Brightness value not in range [%d,%d]: clipping value to %0.1f\n",
+                   -10, 10, hue->brightness);
+        }
+    }
+
     if (hue->hue_deg_expr) {
         hue->hue_deg = av_expr_eval(hue->hue_deg_pexpr, hue->var_values, NULL);
         hue->hue = hue->hue_deg * M_PI / 180;
@@ -305,15 +351,19 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)
     }
 
     av_log(inlink->dst, AV_LOG_DEBUG,
-           "H:%0.1f*PI h:%0.1f s:%0.f t:%0.1f n:%d\n",
-           hue->hue/M_PI, hue->hue_deg, hue->saturation,
+           "H:%0.1f*PI h:%0.1f s:%0.f b:%0.f t:%0.1f n:%d\n",
+           hue->hue/M_PI, hue->hue_deg, hue->saturation, hue->brightness,
            hue->var_values[VAR_T], (int)hue->var_values[VAR_N]);
 
     compute_sin_and_cos(hue);
     if (old_hue_sin != hue->hue_sin || old_hue_cos != hue->hue_cos)
         create_chrominance_lut(hue, hue->hue_cos, hue->hue_sin);
 
+    if (old_brightness != hue->brightness && hue->brightness)
+        create_luma_lut(hue);
+
     if (!direct) {
+        if (!hue->brightness)
             av_image_copy_plane(outpic->data[0], outpic->linesize[0],
                                 inpic->data[0],  inpic->linesize[0],
                                 inlink->w, inlink->h);
@@ -327,6 +377,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *inpic)
               inpic->data[1],  inpic->data[2],  inpic->linesize[1],
               FF_CEIL_RSHIFT(inlink->w, hue->hsub),
               FF_CEIL_RSHIFT(inlink->h, hue->vsub));
+    if (hue->brightness)
+        apply_luma_lut(hue, outpic->data[0], outpic->linesize[0],
+                       inpic->data[0], inpic->linesize[0], inlink->w, inlink->h);
 
     if (!direct)
         av_frame_free(&inpic);
@@ -355,6 +408,8 @@ static int process_command(AVFilterContext *ctx, const char *cmd, const char *ar
         av_freep(&hue->hue_deg_expr);
     } else if (!strcmp(cmd, "s")) {
         SET_EXPR(saturation, "s");
+    } else if (!strcmp(cmd, "b")) {
+        SET_EXPR(brightness, "b");
     } else
         return AVERROR(ENOSYS);