validate:ssim: Allow specifying file framerate to use frame numbers during comparison

docs/plugins/ssim.md

@@ -54,6 +54,9 @@ The following parameters can be passed in the configuration file:
    used to configure the following configuration expressions. In practice this
    means that it will change the default values for the other configuration
    expressions.
+ - framerate: (GstFraction): The framerate to use to compute frame number from
+   timestamp, allowing to compare frames by 'frame number' instead of trying to
+   match timestamp between reference images and output images.
 
 # Example #
 

validate/gst-libs/gst/video/gstvalidatessim.c

@@ -71,6 +71,7 @@ struct _GstValidateSsimPrivate
   gfloat min_lowest_similarity;
 
   GHashTable *ref_frames_cache;
+  gint fps_n, fps_d;
 };
 
 G_DEFINE_TYPE_WITH_CODE (GstValidateSsim, gst_validate_ssim,
@@ -532,6 +533,16 @@ _find_frame (GstValidateSsim * self, GArray * frames, GstClockTime ts,
   guint i;
   Frame *lframe = &g_array_index (frames, Frame, 0);
 
+  if (self->priv->fps_n) {
+    gint64 frame_number = gst_util_uint64_scale (ts, self->priv->fps_n,
+        self->priv->fps_d * GST_SECOND);
+
+    if (frames->len < frame_number)
+      return NULL;
+
+    return &g_array_index (frames, Frame, frame_number);
+  }
+
   if (frames->len == 1) {
     Frame *iframe = &g_array_index (frames, Frame, 0);
 
@@ -1002,13 +1013,16 @@ gst_validate_ssim_init (GstValidateSsim * self)
 
 GstValidateSsim *
 gst_validate_ssim_new (GstValidateRunner * runner,
-    gfloat min_avg_similarity, gfloat min_lowest_similarity)
+    gfloat min_avg_similarity, gfloat min_lowest_similarity,
+    gint fps_n, gint fps_d)
 {
   GstValidateSsim *self =
       g_object_new (GST_VALIDATE_SSIM_TYPE, "validate-runner", runner, NULL);
 
   self->priv->min_avg_similarity = min_avg_similarity;
   self->priv->min_lowest_similarity = min_lowest_similarity;
+  self->priv->fps_n = fps_n;
+  self->priv->fps_d = fps_d;
 
   gst_validate_reporter_set_name (GST_VALIDATE_REPORTER (self),
       g_strdup ("gst-validate-images-checker"));

validate/gst-libs/gst/video/gstvalidatessim.h

@@ -60,7 +60,9 @@ GType gst_validate_ssim_get_type                (void);
 
 GstValidateSsim * gst_validate_ssim_new         (GstValidateRunner *runner,
                                                  gfloat min_avg_similarity,
-                                                 gfloat min_lowest_similarity);
+                                                 gfloat min_lowest_similarity,
+                                                 gint fps_n,
+                                                 gint fps_d);
 
 gboolean gst_validate_ssim_compare_image_files  (GstValidateSsim *self, const gchar *ref_file,
                                                  const gchar * file, gfloat * mean, gfloat * lowest,

validate/plugins/ssim/gstvalidatessim.c

@@ -129,6 +129,7 @@ runner_stopping (GstValidateRunner * runner, ValidateSsimOverride * self)
   const gchar *compared_files_dir =
       gst_structure_get_string (self->priv->config,
       "reference-images-dir");
+  gint fps_n = 0, fps_d = 1;
 
   if (!self->priv->is_attached) {
     gchar *config_str = gst_structure_to_string (self->priv->config);
@@ -154,8 +155,10 @@ runner_stopping (GstValidateRunner * runner, ValidateSsimOverride * self)
   gst_structure_get_double (self->priv->config, "min-lowest-priority",
       &min_lowest_similarity);
 
+  gst_structure_get_fraction (self->priv->config, "framerate", &fps_n, &fps_d);
   ssim =
-      gst_validate_ssim_new (runner, min_avg_similarity, min_lowest_similarity);
+      gst_validate_ssim_new (runner, min_avg_similarity, min_lowest_similarity,
+      fps_n, fps_d);
 
   nfiles = self->priv->frames->len;
   for (i = 0; i < nfiles; i++) {

validate/tools/gst-validate-images-check.c

@@ -93,7 +93,8 @@ main (int argc, char **argv)
 
   runner = gst_validate_runner_new ();
   ssim =
-      gst_validate_ssim_new (runner, min_avg_similarity, min_lowest_similarity);
+      gst_validate_ssim_new (runner, min_avg_similarity, min_lowest_similarity,
+      0, 1);
 
   gst_validate_ssim_compare_image_files (ssim, argv[1], argv[2], &mssim,
       &lowest, &highest, outfolder);