[FFmpeg-devel] libavfilter/vf_signalstats.c: add new hsl(Hue, Saturation, Lightness) for filter signalstats v2

diff --git a/libavfilter/vf_signalstats.c b/libavfilter/vf_signalstats.c
index b4d1029296..c6c505ec30 100644
--- a/libavfilter/vf_signalstats.c
+++ b/libavfilter/vf_signalstats.c
@@ -2,6 +2,8 @@ 
  * Copyright (c) 2010 Mark Heath mjpeg0 @ silicontrip dot org
  * Copyright (c) 2014 Clément Bœsch
  * Copyright (c) 2014 Dave Rice @dericed
+ * Copyright (c) 2022 Wang Wei <wangwei1237@gmail.com>
+ * Copyright (c) 2022 Liu yizhuo <yizhuo.liu753@gmail.com>
  *
  * This file is part of FFmpeg.
  *
@@ -18,6 +20,11 @@ 
  * 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
+ *
+*  @file
+ * Add Calculate the HSL color space information.
+ * HSL is a color space that is more perceptually uniform than RGB :
+ *     https://en.wikipedia.org/wiki/HSL_and_HSV
  */
 
 #include "libavutil/intreadwrite.h"
@@ -25,6 +32,7 @@ 
 #include "libavutil/pixdesc.h"
 #include "filters.h"
 #include "internal.h"
+#include "libswscale/swscale.h"
 
 enum FilterMode {
     FILTER_NONE = -1,
@@ -36,6 +44,8 @@  enum FilterMode {
 
 typedef struct SignalstatsContext {
     const AVClass *class;
+    int lumah;      // height of luma plane
+    int lumaw;      // width of luma plane
     int chromah;    // height of chroma plane
     int chromaw;    // width of chroma plane
     int hsub;       // horizontal subsampling
@@ -56,6 +66,11 @@  typedef struct SignalstatsContext {
 
     AVFrame *frame_sat;
     AVFrame *frame_hue;
+    AVFrame *frame_rgb;
+    
+    int *hsl_h;
+    int *hsl_s;
+    int *hsl_l;
 } SignalstatsContext;
 
 typedef struct ThreadData {
@@ -65,9 +80,21 @@  typedef struct ThreadData {
 
 typedef struct ThreadDataHueSatMetrics {
     const AVFrame *src;
-    AVFrame *dst_sat, *dst_hue;
+    AVFrame *dst_sat, *dst_hue, *dst_h, *dst_s, *dst_l;
 } ThreadDataHueSatMetrics;
 
+typedef struct ThreadDataHSLMetrics {
+    const AVFrame *src;
+    int *dst_h, *dst_s, *dst_l;
+} ThreadDataHSLMetrics;
+
+typedef float num;
+
+static const float EPSILON = 1e-9;
+
+/** @brief Equal of A and B */
+#define EQ(A,B)    ((fabs((A) - (B)) < EPSILON) ? 1 : 0)
+
 #define OFFSET(x) offsetof(SignalstatsContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
@@ -110,11 +137,15 @@  static av_cold void uninit(AVFilterContext *ctx)
     av_frame_free(&s->frame_prev);
     av_frame_free(&s->frame_sat);
     av_frame_free(&s->frame_hue);
+    av_frame_free(&s->frame_rgb);
     av_freep(&s->jobs_rets);
     av_freep(&s->histy);
     av_freep(&s->histu);
     av_freep(&s->histv);
     av_freep(&s->histsat);
+    av_freep(&s->hsl_h);
+    av_freep(&s->hsl_s);
+    av_freep(&s->hsl_l);
 }
 
 // TODO: add more
@@ -151,6 +182,23 @@  static AVFrame *alloc_frame(enum AVPixelFormat pixfmt, int w, int h)
     return frame;
 }
 
+static int config_input(AVFilterLink *inlink)
+{
+    // Video input data avilable
+    AVFilterContext *ctx = inlink->dst;
+    SignalstatsContext *s = ctx->priv;
+    
+    // free previous buffers in case they are allocated already
+    av_frame_free(&s->frame_rgb);
+    s->frame_rgb = alloc_frame(AV_PIX_FMT_RGB24, inlink->w, inlink->h);
+
+    if (!s->frame_rgb) {
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -172,12 +220,22 @@  static int config_output(AVFilterLink *outlink)
     outlink->w = inlink->w;
     outlink->h = inlink->h;
 
+    s->lumaw   = inlink->w;
+    s->lumah   = inlink->h;
+
     s->chromaw = AV_CEIL_RSHIFT(inlink->w, s->hsub);
     s->chromah = AV_CEIL_RSHIFT(inlink->h, s->vsub);
 
     s->fs = inlink->w * inlink->h;
     s->cfs = s->chromaw * s->chromah;
 
+    s->hsl_h = av_malloc_array(s->lumah, sizeof(*s->hsl_h));
+    s->hsl_s = av_malloc_array(s->lumah, sizeof(*s->hsl_s));
+    s->hsl_l = av_malloc_array(s->lumah, sizeof(*s->hsl_l));
+    if (!s->hsl_h || !s->hsl_s || !s->hsl_l) {
+        return AVERROR(ENOMEM);
+    }
+
     s->nb_jobs   = FFMAX(1, FFMIN(inlink->h, ff_filter_get_nb_threads(ctx)));
     s->jobs_rets = av_malloc_array(s->nb_jobs, sizeof(*s->jobs_rets));
     if (!s->jobs_rets)
@@ -455,6 +513,110 @@  static const struct {
     {NULL}
 };
 
+static void YUV2RGB(const AVFrame* src, enum AVPixelFormat dstFormat, AVFrame* dst)
+{
+    int width  = src->width;
+    int height = src->height;
+    
+    struct SwsContext* conversion = NULL;
+    conversion = sws_getContext(width,
+                                height,
+                                (enum AVPixelFormat)src->format,
+                                width,
+                                height,
+                                dstFormat,
+                                SWS_FAST_BILINEAR,
+                                NULL,
+                                NULL,
+                                NULL);
+    sws_scale(conversion, (const uint8_t * const *)src->data, src->linesize, 0, height, dst->data, dst->linesize);
+    sws_freeContext(conversion);
+}
+
+/**
+ * @brief Convert an sRGB color to Hue-Saturation-Lightness (HSL)
+ *
+ * @param H, S, L pointers to hold the result
+ * @param R, G, B the input sRGB values scaled in [0,1]
+ *
+ * This routine transforms from sRGB to the double hexcone HSL color space
+ * The sRGB values are assumed to be between 0 and 1.  The outputs are
+ *   H = hexagonal hue angle                (0 <= H < 360),
+ *   S = { C/(2L)     if L <= 1/2           (0 <= S <= 1),
+ *       { C/(2 - 2L) if L >  1/2
+ *   L = (max(R',G',B') + min(R',G',B'))/2  (0 <= L <= 1),
+ * where C = max(R',G',B') - min(R',G',B').
+ *
+ * Wikipedia: http://en.wikipedia.org/wiki/HSL_and_HSV
+ */
+static void RGB2HSL(num *H, num *S, num *L, num R, num G, num B)
+{
+    num Max = FFMAX3(R, G, B);
+    num Min = FFMIN3(R, G, B);
+    num C = Max - Min;
+
+    *L = (Max + Min) / 2;
+    
+    if (C > 0) {
+        if (EQ(Max, R)) {
+            *H = (G - B) / C;
+            
+            if (G < B) {
+                *H += 6;
+            }
+        } else if (EQ(Max, G)) {
+            *H = 2 + (B - R) / C;
+        } else {
+            *H = 4 + (R - G) / C;
+        }
+
+        *H *= 60;
+        *S = (*L <= 0.5) ? (C/(2*(*L))) : (C/(2 - 2*(*L)));
+    } else {
+        *H = *S = 0;
+    }
+}
+
+static int compute_hsl(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    int i, j;
+    num H, S, L;
+    ThreadDataHSLMetrics *td = arg;
+    const SignalstatsContext *s = ctx->priv;
+    const AVFrame *src = td->src;
+    int *dst_h = td->dst_h;
+    int *dst_s = td->dst_s;
+    int *dst_l = td->dst_l;
+    
+    const int slice_start = (s->lumah * jobnr    ) / nb_jobs;
+    const int slice_end   = (s->lumah * (jobnr+1)) / nb_jobs;
+
+    const int lsz_src = src->linesize[0];
+    const uint8_t *p_src = src->data[0] + slice_start * lsz_src;
+
+    for (j = slice_start; j < slice_end; j++) {
+        int line_h = 0, line_s = 0, line_l = 0;
+        for (i = 0; i < s->lumaw; i++) {
+            const uint8_t rgbr = p_src[3 * i];
+            const uint8_t rgbg = p_src[3 * i + 1];
+            const uint8_t rgbb = p_src[3 * i + 2];
+            
+            RGB2HSL(&H, &S, &L, 1.0 * rgbr / 255, 1.0 * rgbg / 255, 1.0 * rgbb / 255);
+            line_h += (uint16_t)(H + 0.5);
+            line_s += (uint8_t)(S * 100 + 0.5);
+            line_l += (uint8_t)(L * 100 + 0.5);
+        }
+        
+        dst_h[j] = line_h / s->lumaw;
+        dst_s[j] = line_s / s->lumaw;
+        dst_l[j] = line_l / s->lumaw;
+
+        p_src += lsz_src;
+    }
+
+    return 0;
+}
+
 static int compute_sat_hue_metrics8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     int i, j;
@@ -562,6 +724,7 @@  static int filter_frame8(AVFilterLink *link, AVFrame *in)
     int accy, accu, accv;
     int accsat, acchue = 0;
     int medhue, maxhue;
+    int avgh = 0, avgs = 0, avgl = 0;
     int toty = 0, totu = 0, totv = 0, totsat=0;
     int tothue = 0;
     int dify = 0, difu = 0, difv = 0;
@@ -604,6 +767,28 @@  static int filter_frame8(AVFilterLink *link, AVFrame *in)
     ff_filter_execute(ctx, compute_sat_hue_metrics8, &td_huesat,
                       NULL, FFMIN(s->chromah, ff_filter_get_nb_threads(ctx)));
 
+    // Calculate HSL information.
+    YUV2RGB(in, AV_PIX_FMT_RGB24, s->frame_rgb);
+    ThreadDataHSLMetrics td_hsl = {
+        .src   = s->frame_rgb,
+        .dst_h = s->hsl_h,
+        .dst_s = s->hsl_s,
+        .dst_l = s->hsl_l,
+    };
+    ff_filter_execute(ctx, compute_hsl, &td_hsl,
+                      NULL, FFMIN(link->h, ff_filter_get_nb_threads(ctx)));
+    
+    int sumh = 0, sums = 0, suml = 0;
+    for (j = 0; j < s->lumah; j++) {
+        sumh += s->hsl_h[j];
+        sums += s->hsl_s[j];
+        suml += s->hsl_l[j];
+    }
+
+    avgh = sumh / s->lumah;
+    avgs = sums / s->lumah;
+    avgl = suml / s->lumah;
+
     // Calculate luma histogram and difference with previous frame or field.
     memset(s->histy, 0, s->maxsize * sizeof(*s->histy));
     for (j = 0; j < link->h; j++) {
@@ -746,6 +931,10 @@  static int filter_frame8(AVFilterLink *link, AVFrame *in)
     SET_META("HUEMED",  "%d", medhue);
     SET_META("HUEAVG",  "%g", 1.0 * tothue / s->cfs);
 
+    SET_META("HAVG",    "%d", avgh);
+    SET_META("SAVG",    "%d", avgs);
+    SET_META("LAVG",    "%d", avgl);
+
     SET_META("YDIF",    "%g", 1.0 * dify / s->fs);
     SET_META("UDIF",    "%g", 1.0 * difu / s->cfs);
     SET_META("VDIF",    "%g", 1.0 * difv / s->cfs);
@@ -793,6 +982,7 @@  static int filter_frame16(AVFilterLink *link, AVFrame *in)
     int accy, accu, accv;
     int accsat, acchue = 0;
     int medhue, maxhue;
+    int avgh = 0, avgs = 0, avgl = 0;
     int64_t toty = 0, totu = 0, totv = 0, totsat=0;
     int64_t tothue = 0;
     int64_t dify = 0, difu = 0, difv = 0;
@@ -835,6 +1025,28 @@  static int filter_frame16(AVFilterLink *link, AVFrame *in)
     ff_filter_execute(ctx, compute_sat_hue_metrics16, &td_huesat,
                       NULL, FFMIN(s->chromah, ff_filter_get_nb_threads(ctx)));
 
+    // Calculate HSL information.
+    YUV2RGB(in, AV_PIX_FMT_RGB24, s->frame_rgb);
+    ThreadDataHSLMetrics td_hsl = {
+        .src   = s->frame_rgb,
+        .dst_h = s->hsl_h,
+        .dst_s = s->hsl_s,
+        .dst_l = s->hsl_l,
+    };
+    ff_filter_execute(ctx, compute_hsl, &td_hsl,
+                      NULL, FFMIN(link->h, ff_filter_get_nb_threads(ctx)));
+    
+    int sumh = 0, sums = 0, suml = 0;
+    for (j = 0; j < s->lumah; j++) {
+        sumh += s->hsl_h[j];
+        sums += s->hsl_s[j];
+        suml += s->hsl_l[j];
+    }
+
+    avgh = sumh / s->lumah;
+    avgs = sums / s->lumah;
+    avgl = suml / s->lumah;
+
     // Calculate luma histogram and difference with previous frame or field.
     memset(s->histy, 0, s->maxsize * sizeof(*s->histy));
     for (j = 0; j < link->h; j++) {
@@ -976,6 +1188,10 @@  static int filter_frame16(AVFilterLink *link, AVFrame *in)
     SET_META("UDIF",    "%g", 1.0 * difu / s->cfs);
     SET_META("VDIF",    "%g", 1.0 * difv / s->cfs);
 
+    SET_META("HAVG",    "%d", avgh);
+    SET_META("SAVG",    "%d", avgs);
+    SET_META("LAVG",    "%d", avgl);
+
     SET_META("YBITDEPTH", "%d", compute_bit_depth(masky));
     SET_META("UBITDEPTH", "%d", compute_bit_depth(masku));
     SET_META("VBITDEPTH", "%d", compute_bit_depth(maskv));
@@ -1009,6 +1225,7 @@  static const AVFilterPad signalstats_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
+        .config_props   = config_input,
         .filter_frame   = filter_frame,
     },
 };
diff --git a/tests/ref/fate/filter-metadata-signalstats-yuv420p b/tests/ref/fate/filter-metadata-signalstats-yuv420p
index a42acc8f2b..695a93dedc 100644
--- a/tests/ref/fate/filter-metadata-signalstats-yuv420p
+++ b/tests/ref/fate/filter-metadata-signalstats-yuv420p
@@ -1 +1 @@ 
-pts=0|tag:lavfi.signalstats.UBITDEPTH=1|tag:lavfi.signalstats.YMIN=235|tag:lavfi.signalstats.YLOW=235|tag:lavfi.signalstats.YAVG=235|tag:lavfi.signalstats.YHIGH=235|tag:lavfi.signalstats.YMAX=235|tag:lavfi.signalstats.UMIN=128|tag:lavfi.signalstats.ULOW=128|tag:lavfi.signalstats.UAVG=128|tag:lavfi.signalstats.UHIGH=128|tag:lavfi.signalstats.UMAX=128|tag:lavfi.signalstats.VMIN=128|tag:lavfi.signalstats.VLOW=128|tag:lavfi.signalstats.VAVG=128|tag:lavfi.signalstats.VHIGH=128|tag:lavfi.signalstats.VMAX=128|tag:lavfi.signalstats.SATMIN=0|tag:lavfi.signalstats.SATLOW=0|tag:lavfi.signalstats.SATAVG=0|tag:lavfi.signalstats.SATHIGH=0|tag:lavfi.signalstats.SATMAX=0|tag:lavfi.signalstats.HUEMED=180|tag:lavfi.signalstats.HUEAVG=180|tag:lavfi.signalstats.YDIF=0|tag:lavfi.signalstats.UDIF=0|tag:lavfi.signalstats.VDIF=0|tag:lavfi.signalstats.YBITDEPTH=6|tag:lavfi.signalstats.VBITDEPTH=1
+pts=0|tag:lavfi.signalstats.UBITDEPTH=1|tag:lavfi.signalstats.YMIN=235|tag:lavfi.signalstats.YLOW=235|tag:lavfi.signalstats.YAVG=235|tag:lavfi.signalstats.YHIGH=235|tag:lavfi.signalstats.YMAX=235|tag:lavfi.signalstats.UMIN=128|tag:lavfi.signalstats.ULOW=128|tag:lavfi.signalstats.UAVG=128|tag:lavfi.signalstats.UHIGH=128|tag:lavfi.signalstats.UMAX=128|tag:lavfi.signalstats.VMIN=128|tag:lavfi.signalstats.VLOW=128|tag:lavfi.signalstats.VAVG=128|tag:lavfi.signalstats.VHIGH=128|tag:lavfi.signalstats.VMAX=128|tag:lavfi.signalstats.SATMIN=0|tag:lavfi.signalstats.SATLOW=0|tag:lavfi.signalstats.SATAVG=0|tag:lavfi.signalstats.SATHIGH=0|tag:lavfi.signalstats.SATMAX=0|tag:lavfi.signalstats.HUEMED=180|tag:lavfi.signalstats.HUEAVG=180|tag:lavfi.signalstats.HAVG=0|tag:lavfi.signalstats.SAVG=0|tag:lavfi.signalstats.LAVG=99|tag:lavfi.signalstats.YDIF=0|tag:lavfi.signalstats.UDIF=0|tag:lavfi.signalstats.VDIF=0|tag:lavfi.signalstats.YBITDEPTH=6|tag:lavfi.signalstats.VBITDEPTH=1
\ No newline at end of file
diff --git a/tests/ref/fate/filter-metadata-signalstats-yuv420p10 b/tests/ref/fate/filter-metadata-signalstats-yuv420p10
index 1e5afd0820..7245a61fff 100644
--- a/tests/ref/fate/filter-metadata-signalstats-yuv420p10
+++ b/tests/ref/fate/filter-metadata-signalstats-yuv420p10
@@ -1 +1 @@ 
-pts=0|tag:lavfi.signalstats.UBITDEPTH=2|tag:lavfi.signalstats.YMIN=943|tag:lavfi.signalstats.YLOW=943|tag:lavfi.signalstats.YAVG=943|tag:lavfi.signalstats.YHIGH=943|tag:lavfi.signalstats.YMAX=943|tag:lavfi.signalstats.UMIN=514|tag:lavfi.signalstats.ULOW=514|tag:lavfi.signalstats.UAVG=514|tag:lavfi.signalstats.UHIGH=514|tag:lavfi.signalstats.UMAX=514|tag:lavfi.signalstats.VMIN=514|tag:lavfi.signalstats.VLOW=514|tag:lavfi.signalstats.VAVG=514|tag:lavfi.signalstats.VHIGH=514|tag:lavfi.signalstats.VMAX=514|tag:lavfi.signalstats.SATMIN=2|tag:lavfi.signalstats.SATLOW=2|tag:lavfi.signalstats.SATAVG=2|tag:lavfi.signalstats.SATHIGH=2|tag:lavfi.signalstats.SATMAX=2|tag:lavfi.signalstats.HUEMED=225|tag:lavfi.signalstats.HUEAVG=225|tag:lavfi.signalstats.YDIF=0|tag:lavfi.signalstats.UDIF=0|tag:lavfi.signalstats.VDIF=0|tag:lavfi.signalstats.YBITDEPTH=8|tag:lavfi.signalstats.VBITDEPTH=2
+pts=0|tag:lavfi.signalstats.UBITDEPTH=2|tag:lavfi.signalstats.YMIN=943|tag:lavfi.signalstats.YLOW=943|tag:lavfi.signalstats.YAVG=943|tag:lavfi.signalstats.YHIGH=943|tag:lavfi.signalstats.YMAX=943|tag:lavfi.signalstats.UMIN=514|tag:lavfi.signalstats.ULOW=514|tag:lavfi.signalstats.UAVG=514|tag:lavfi.signalstats.UHIGH=514|tag:lavfi.signalstats.UMAX=514|tag:lavfi.signalstats.VMIN=514|tag:lavfi.signalstats.VLOW=514|tag:lavfi.signalstats.VAVG=514|tag:lavfi.signalstats.VHIGH=514|tag:lavfi.signalstats.VMAX=514|tag:lavfi.signalstats.SATMIN=2|tag:lavfi.signalstats.SATLOW=2|tag:lavfi.signalstats.SATAVG=2|tag:lavfi.signalstats.SATHIGH=2|tag:lavfi.signalstats.SATMAX=2|tag:lavfi.signalstats.HUEMED=225|tag:lavfi.signalstats.HUEAVG=225|tag:lavfi.signalstats.YDIF=0|tag:lavfi.signalstats.UDIF=0|tag:lavfi.signalstats.VDIF=0|tag:lavfi.signalstats.HAVG=300|tag:lavfi.signalstats.SAVG=100|tag:lavfi.signalstats.LAVG=100|tag:lavfi.signalstats.YBITDEPTH=8|tag:lavfi.signalstats.VBITDEPTH=2
\ No newline at end of file