/* GStreamer * * Copyright (C) 2015 Raspberry Pi Foundation * Author: Thibault Saunier * * gstvalidatessim.c: GstValidateActionTypes to use with ssim applications * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #define _GNU_SOURCE #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include "../../gst-libs/gst/video/gstvalidatessim.h" #include "../../gst/validate/gst-validate-report.h" #include "../../gst/validate/gst-validate-pad-monitor.h" #include "../../gst/validate/gst-validate-reporter.h" #include "../../gst/validate/validate.h" #include "../../gst/validate/gst-validate-scenario.h" #include "../../gst/validate/gst-validate-utils.h" #define SSIM_WRONG_FORMAT g_quark_from_static_string ("validatessim::wrong-format") #define SSIM_CONVERSION_ERROR g_quark_from_static_string ("validatessim::conversion-error") #define SSIM_SAVING_ERROR g_quark_from_static_string ("validatessim::saving-error") #define MONITOR_DATA g_quark_from_static_string ("validate-ssim-monitor-data") #define NOT_ATTACHED g_quark_from_static_string ("validatessim::not-attached") typedef struct _ValidateSsimOverridePrivate ValidateSsimOverridePrivate; typedef struct { GstValidateOverride parent; ValidateSsimOverridePrivate *priv; } ValidateSsimOverride; typedef struct { GstValidateOverrideClass parent; } ValidateSsimOverrideClass; typedef struct { gchar *path; GstClockTime position; guint width, height; } Frame; static void free_frame (Frame * frame) { g_free (frame->path); } struct _ValidateSsimOverridePrivate { gchar *outdir; gchar *result_outdir; GstStructure *config; gboolean is_attached; GstVideoConverter *converter; GstCaps *last_caps; GstVideoInfo in_info; GstVideoInfo out_info; GArray *frames; GstClockTime recurrence; GstClockTime last_dump_position; /* Always used in the streaming thread */ gboolean needs_reconfigure; GstVideoFormat save_format; const gchar *ext; GstVideoFormat ref_format; const gchar *ref_ext; }; static GType validate_ssim_override_get_type (void); #define VALIDATE_SSIM_OVERRIDE_TYPE (validate_ssim_override_get_type ()) #define VALIDATE_SSIM_OVERRIDE(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), VALIDATE_SSIM_OVERRIDE_TYPE, ValidateSsimOverride)) #define VALIDATE_SSIM_OVERRIDE_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), VALIDATE_SSIM_OVERRIDE_TYPE, ValidateSsimOverrideClass)) #define IS_VALIDATE_SSIM_OVERRIDE(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), VALIDATE_SSIM_OVERRIDE_TYPE)) #define IS_VALIDATE_SSIM_OVERRIDE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), VALIDATE_SSIM_OVERRIDE_TYPE)) #define VALIDATE_SSIM_OVERRIDE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), VALIDATE_SSIM_OVERRIDE_TYPE, ValidateSsimOverrideClass)) /* *INDENT-OFF* */ G_DEFINE_TYPE_WITH_PRIVATE (ValidateSsimOverride, validate_ssim_override, GST_TYPE_VALIDATE_OVERRIDE) /* *INDENT-ON* */ static void runner_stopping (GstValidateRunner * runner, ValidateSsimOverride * self) { GstValidateSsim *ssim; guint i, nfiles; gfloat mssim = 0, lowest = 1, highest = -1, total_avg = 0; gint npassed = 0, nfailures = 0; gdouble min_avg_similarity = 0.95, min_lowest_similarity = -1.0, min_avg = 1.0, min_min = 1.0; 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); GST_VALIDATE_REPORT (self, NOT_ATTACHED, "The test ended without SSIM being attached for config %s", config_str); g_free (config_str); return; } if (!compared_files_dir) { return; } gst_validate_printf (self, "Running frame comparison between images from '%s' and '%s' %s%s.\n", compared_files_dir, self->priv->outdir, self->priv->result_outdir ? ". Issues can be visialized in " : " (set 'result-output-dir' in the config file to visualize the result)", self->priv->result_outdir ? self->priv->result_outdir : ""); gst_structure_get_double (self->priv->config, "min-avg-priority", &min_avg_similarity); 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, fps_n, fps_d); nfiles = self->priv->frames->len; for (i = 0; i < nfiles; i++) { Frame *frame = &g_array_index (self->priv->frames, Frame, i); gchar *refname, *ref_path, *bname = g_path_get_basename (frame->path); if (self->priv->ref_format == GST_VIDEO_FORMAT_ENCODED) refname = g_strdup_printf ("*.%s", self->priv->ref_ext); else refname = g_strdup_printf ("*.%dx%d.%s", frame->width, frame->height, self->priv->ref_ext); ref_path = g_build_path (G_DIR_SEPARATOR_S, compared_files_dir, refname, NULL); if (!gst_validate_ssim_compare_image_files (ssim, ref_path, frame->path, &mssim, &lowest, &highest, self->priv->result_outdir)) nfailures++; else npassed++; g_free (ref_path); min_avg = MIN (min_avg, mssim); min_min = MIN (lowest, min_min); total_avg += mssim; gst_validate_print_position (frame->position, GST_CLOCK_TIME_NONE, 1.0, g_strdup_printf (" %d / %d avg: %f min: %f (Passed: %d failed: %d)", i + 1, nfiles, mssim, lowest, npassed, nfailures)); g_free (bname); } gst_validate_printf (NULL, "\nAverage similarity: %f, min_avg: %f, min_min: %f\n", total_avg / nfiles, min_avg, min_min); } static void _runner_set (GObject * object, GParamSpec * pspec, gpointer user_data) { ValidateSsimOverride *self = VALIDATE_SSIM_OVERRIDE (object); GstValidateRunner *runner = gst_validate_reporter_get_runner (GST_VALIDATE_REPORTER (self)); g_signal_connect (runner, "stopping", G_CALLBACK (runner_stopping), self); gst_object_unref (runner); } static ValidateSsimOverride * validate_ssim_override_new (GstStructure * config) { const gchar *format; ValidateSsimOverride *self = g_object_new (VALIDATE_SSIM_OVERRIDE_TYPE, NULL); self->priv->outdir = g_strdup (gst_structure_get_string (config, "output-dir")); if (self->priv->outdir == NULL) { gchar *template = g_build_filename (g_get_tmp_dir (), "validatessim-XXXXXX", NULL); self->priv->outdir = g_mkdtemp (template); } if (!g_file_test (self->priv->outdir, G_FILE_TEST_IS_DIR)) { if (g_mkdir_with_parents (self->priv->outdir, 0755) != 0) { GST_ERROR ("Could not create directory %s", self->priv->outdir); g_object_unref (self); return NULL; } } self->priv->config = gst_structure_copy (config); self->priv->result_outdir = g_strdup (gst_structure_get_string (config, "result-output-dir")); format = gst_structure_get_string (config, "output-video-format"); if (!format) { self->priv->save_format = GST_VIDEO_FORMAT_ENCODED; self->priv->ext = "png"; } else { self->priv->save_format = gst_video_format_from_string (format); self->priv->ext = format; } if (self->priv->save_format == GST_VIDEO_FORMAT_UNKNOWN) { GST_ERROR ("Uknown video format: %s", format); gst_object_unref (self); return NULL; } format = gst_structure_get_string (config, "reference-video-format"); if (!format) { self->priv->ref_ext = "png"; self->priv->ref_format = GST_VIDEO_FORMAT_ENCODED; } else { self->priv->ref_format = gst_video_format_from_string (format); if (self->priv->ref_format == GST_VIDEO_FORMAT_UNKNOWN) { GST_ERROR ("Uknown video format: %s", format); gst_object_unref (self); return NULL; } self->priv->ref_ext = format; } gst_validate_utils_get_clocktime (config, "check-recurrence", &self->priv->recurrence); g_signal_connect (self, "notify::validate-runner", G_CALLBACK (_runner_set), NULL); return self; } static gboolean _can_attach (GstValidateOverride * override, GstValidateMonitor * monitor) { guint i; GstPad *pad = NULL; GstCaps *template_caps; GstElement *element = NULL; GstStructure *structure; gboolean res = FALSE; ValidateSsimOverride *self = VALIDATE_SSIM_OVERRIDE (override); if (self->priv->is_attached) { GST_ERROR_OBJECT (override, "Already attached"); goto fail; } if (!GST_IS_VALIDATE_PAD_MONITOR (monitor)) { goto fail; } pad = GST_PAD (gst_validate_monitor_get_target (monitor)); element = gst_validate_monitor_get_element (monitor); if (!element) { GST_INFO_OBJECT (monitor, "Not in an element yet, can't attach"); goto fail; } if ((gst_validate_element_has_klass (element, "Converter") || gst_validate_element_has_klass (element, "Filter") || gst_validate_element_has_klass (element, "Decoder")) && GST_PAD_IS_SINK (pad)) { GST_INFO_OBJECT (override, "Not attaching on filter or decoder sinkpads"); goto fail; } if (!GST_PAD_PAD_TEMPLATE (pad)) { GST_INFO_OBJECT (pad, "Doesn't have template, can't use it %" GST_PTR_FORMAT, gst_pad_query_caps (pad, NULL)); return FALSE; } template_caps = GST_PAD_TEMPLATE_CAPS (GST_PAD_PAD_TEMPLATE (pad)); if (gst_caps_is_any (template_caps)) { res = TRUE; goto done; } for (i = 0; i < gst_caps_get_size (template_caps); i++) { structure = gst_caps_get_structure (template_caps, i); if (gst_structure_has_name (structure, "video/x-raw")) { res = TRUE; break; } } done: if (res) { gchar *path = gst_object_get_path_string (GST_OBJECT (pad)); GST_INFO_OBJECT (override, "Wrapping %" GST_PTR_FORMAT, pad); gst_validate_reporter_set_name (GST_VALIDATE_REPORTER (override), g_strdup_printf ("ssim-override-%s", path)); gst_validate_printf (self, "Using %s as output directory\n", self->priv->outdir); g_free (path); } if (pad) gst_object_unref (pad); if (element) gst_object_unref (element); return res; fail: res = FALSE; goto done; } static void validate_ssim_override_attached (GstValidateOverride * override) { ValidateSsimOverride *self = VALIDATE_SSIM_OVERRIDE (override); self->priv->is_attached = TRUE; } static void _finalize (GObject * object) { ValidateSsimOverridePrivate *priv = VALIDATE_SSIM_OVERRIDE (object)->priv; GDir *outdir_handle = NULL; const gchar *filename = NULL; GError *error = NULL; if (priv->converter) gst_video_converter_free (priv->converter); if (priv->last_caps) gst_caps_unref (priv->last_caps); if (priv->config && !gst_structure_has_field (priv->config, "output-dir")) { /* Remove temporary directory contents (expected to be files, no sub-directories). */ outdir_handle = g_dir_open (priv->outdir, 0, &error); if (outdir_handle != NULL) { while ((filename = g_dir_read_name (outdir_handle))) { gchar *path = g_build_path (G_DIR_SEPARATOR_S, priv->outdir, filename, NULL); g_remove (path); g_free (path); } g_dir_close (outdir_handle); } else { GST_ERROR ("Unable to cleanup temporary directory %s: %s", priv->outdir, error->message); g_error_free (error); } g_rmdir (priv->outdir); } g_free (priv->outdir); g_free (priv->result_outdir); g_array_unref (priv->frames); if (priv->config) gst_structure_free (priv->config); } static void validate_ssim_override_class_init (ValidateSsimOverrideClass * klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); GstValidateOverrideClass *override_class = GST_VALIDATE_OVERRIDE_CLASS (klass); gobject_class->finalize = _finalize; override_class->attached = validate_ssim_override_attached; if (!gst_validate_is_initialized ()) return; GST_VALIDATE_OVERRIDE_CLASS (klass)->can_attach = _can_attach; gst_validate_issue_register (gst_validate_issue_new (SSIM_WRONG_FORMAT, "The ValidateSSim plugin can not work with a video format", "The GstValidate ssim plugin was not able to work" " with a video format that flowed in the pipeline." " Make sure you properly configured the plugin", GST_VALIDATE_REPORT_LEVEL_CRITICAL)); gst_validate_issue_register (gst_validate_issue_new (SSIM_CONVERSION_ERROR, "The ValidateSSim plugin could not convert a frame in the needed format", "The GstValidate ssim plugin needs to convert the frame in a colorspace" " it can handle, but it was not possible.", GST_VALIDATE_REPORT_LEVEL_CRITICAL)); gst_validate_issue_register (gst_validate_issue_new (SSIM_SAVING_ERROR, "The ValidateSSim plugin could not save PNG file", "The ValidateSSim plugin could not save PNG file", GST_VALIDATE_REPORT_LEVEL_CRITICAL)); gst_validate_issue_register (gst_validate_issue_new (NOT_ATTACHED, "The ssim override was never attached.", "The ssim override was never attached.", GST_VALIDATE_REPORT_LEVEL_CRITICAL)); } static void validate_ssim_override_init (ValidateSsimOverride * self) { self->priv = validate_ssim_override_get_instance_private (self); self->priv->needs_reconfigure = TRUE; self->priv->frames = g_array_new (TRUE, TRUE, sizeof (Frame)); g_array_set_clear_func (self->priv->frames, (GDestroyNotify) free_frame); } static gboolean _set_videoconvert (ValidateSsimOverride * o, GstValidatePadMonitor * pad_monitor) { GstCaps *caps; GstVideoFormat format; ValidateSsimOverridePrivate *priv = o->priv; GstPad *pad = GST_PAD (gst_validate_monitor_get_target (GST_VALIDATE_MONITOR (pad_monitor))); caps = gst_pad_get_current_caps (pad); gst_object_unref (pad); gst_caps_replace (&priv->last_caps, caps); gst_video_info_init (&priv->in_info); gst_video_info_init (&priv->out_info); if (priv->converter) { gst_video_converter_free (priv->converter); priv->converter = NULL; } if (!gst_video_info_from_caps (&priv->in_info, priv->last_caps)) { GST_VALIDATE_REPORT (o, SSIM_WRONG_FORMAT, "The format %" GST_PTR_FORMAT " is not supported" " by the plugin", pad_monitor->last_caps); return FALSE; } if (GST_VIDEO_INFO_HAS_ALPHA (&priv->in_info)) format = GST_VIDEO_FORMAT_BGRA; else format = GST_VIDEO_FORMAT_BGRx; if (priv->in_info.finfo->format == format) { GST_INFO_OBJECT (o, "No conversion needed"); return TRUE; } if (priv->save_format != GST_VIDEO_FORMAT_ENCODED) format = priv->save_format; gst_video_info_set_format (&priv->out_info, format, priv->in_info.width, priv->in_info.height); priv->out_info.fps_d = priv->in_info.fps_d; priv->out_info.fps_n = priv->in_info.fps_n; priv->converter = gst_video_converter_new (&priv->in_info, &priv->out_info, NULL); return TRUE; } static gboolean has_frame (ValidateSsimOverride * self, gchar * name) { guint i; GArray *frames = self->priv->frames; for (i = 0; i < frames->len; ++i) { if (g_strcmp0 (g_array_index (frames, Frame, i).path, name) == 0) return TRUE; } return FALSE; } static gchar * _get_filename (ValidateSsimOverride * self, GstValidatePadMonitor * monitor, GstClockTime position) { gint i = 0; gchar *outname = NULL, *s; if (self->priv->save_format == GST_VIDEO_FORMAT_ENCODED) s = g_strdup_printf ("%" GST_VALIDATE_SSIM_TIME_FORMAT ".%s", GST_TIME_ARGS (position), self->priv->ext); else s = g_strdup_printf ("%" GST_VALIDATE_SSIM_TIME_FORMAT ".%dx%d.%s", GST_TIME_ARGS (position), self->priv->out_info.width, self->priv->out_info.height, self->priv->ext); outname = g_build_path (G_DIR_SEPARATOR_S, self->priv->outdir, s, NULL); g_free (s); while (has_frame (self, outname)) { g_free (outname); if (self->priv->save_format == GST_VIDEO_FORMAT_ENCODED) s = g_strdup_printf ("%" GST_VALIDATE_SSIM_TIME_FORMAT "-%d.%s", GST_TIME_ARGS (position), i++, self->priv->ext); else s = g_strdup_printf ("%" GST_VALIDATE_SSIM_TIME_FORMAT "-%d.%dx%d.%s", GST_TIME_ARGS (position), i++, self->priv->out_info.width, self->priv->out_info.height, self->priv->ext); outname = g_build_path (G_DIR_SEPARATOR_S, self->priv->outdir, s, NULL); g_free (s); } return outname; } static gboolean _should_dump_buffer (ValidateSsimOverride * self, GstValidatePadMonitor * pad_monitor, GstClockTime position) { ValidateSsimOverridePrivate *priv = self->priv; if (!GST_CLOCK_TIME_IS_VALID (priv->recurrence)) return TRUE; if (priv->needs_reconfigure) return TRUE; /* recurence 0 means, dump exclusively on reconfiguration */ if (priv->recurrence == 0) return FALSE; if (GST_CLOCK_DIFF (priv->last_dump_position, position) >= priv->recurrence) return TRUE; return FALSE; } static gboolean _save_frame (ValidateSsimOverride * self, GstVideoFrame * frame, const gchar * outname) { gboolean res = TRUE; cairo_status_t status; cairo_surface_t *surface; GError *error = NULL; if (self->priv->save_format == GST_VIDEO_FORMAT_ENCODED) { surface = cairo_image_surface_create_for_data (GST_VIDEO_FRAME_PLANE_DATA (frame, 0), CAIRO_FORMAT_RGB24, GST_VIDEO_FRAME_WIDTH (frame), GST_VIDEO_FRAME_HEIGHT (frame), GST_VIDEO_FRAME_PLANE_STRIDE (frame, 0)); if ((status = cairo_surface_write_to_png (surface, outname)) != CAIRO_STATUS_SUCCESS) { GST_VALIDATE_REPORT (self, SSIM_SAVING_ERROR, "Could not save '%s', cairo status is '%s'", outname, cairo_status_to_string (status)); res = FALSE; } cairo_surface_destroy (surface); return res; } if (!g_file_set_contents (outname, GST_VIDEO_FRAME_PLANE_DATA (frame, 0), GST_VIDEO_FRAME_SIZE (frame), &error)) { GST_VALIDATE_REPORT (self, SSIM_SAVING_ERROR, "Could not save %s error: %s", outname, error->message); res = FALSE; } return res; } static void _handle_buffer (GstValidateOverride * override, GstValidatePadMonitor * pad_monitor, GstBuffer * buffer) { gchar *outname = NULL; GstVideoFrame frame; Frame iframe; ValidateSsimOverride *o = VALIDATE_SSIM_OVERRIDE (override); ValidateSsimOverridePrivate *priv = o->priv; GstClockTime position; position = gst_segment_to_stream_time (&pad_monitor->segment, GST_FORMAT_TIME, GST_BUFFER_PTS (buffer)); if (!_should_dump_buffer (o, pad_monitor, position)) { GST_LOG_OBJECT (override, "Not dumping buffer: %" GST_TIME_FORMAT, GST_TIME_ARGS (position)); return; } if (priv->needs_reconfigure) { priv->needs_reconfigure = !_set_videoconvert (o, pad_monitor); } if (priv->converter) { GstVideoFrame inframe; GstBuffer *outbuf; if (!gst_video_frame_map (&inframe, &priv->in_info, buffer, GST_MAP_READ)) { GST_VALIDATE_REPORT (o, SSIM_CONVERSION_ERROR, "Could not map the videoframe %p", buffer); return; } outbuf = gst_buffer_new_allocate (NULL, priv->out_info.size, NULL); if (!gst_video_frame_map (&frame, &priv->out_info, outbuf, GST_MAP_WRITE)) { GST_VALIDATE_REPORT (o, SSIM_CONVERSION_ERROR, "Could not map the outbuffer %p", outbuf); gst_buffer_unref (outbuf); return; } gst_buffer_unref (outbuf); gst_video_converter_frame (priv->converter, &inframe, &frame); gst_video_frame_unmap (&inframe); } else { if (!gst_video_frame_map (&frame, &priv->in_info, buffer, GST_MAP_WRITE)) { GST_VALIDATE_REPORT (o, SSIM_CONVERSION_ERROR, "Could not map the buffer %p", buffer); return; } } outname = _get_filename (o, pad_monitor, position); if (_save_frame (o, &frame, outname)) { priv->last_dump_position = position; iframe.position = position; iframe.path = outname; iframe.width = priv->in_info.width; iframe.height = priv->in_info.height; g_array_append_val (priv->frames, iframe); } gst_video_frame_unmap (&frame); } static void _handle_event (GstValidateOverride * override, GstValidateMonitor * pad_monitor, GstEvent * event) { ValidateSsimOverride *self = VALIDATE_SSIM_OVERRIDE (override); switch (GST_EVENT_TYPE (event)) { case GST_EVENT_FLUSH_STOP: self->priv->needs_reconfigure = TRUE; break; case GST_EVENT_CAPS: self->priv->needs_reconfigure = TRUE; break; default: break; } } static gboolean _map_confg (const GstIdStr * fieldname, GValue * value, GstStructure * structure) { if (!gst_structure_id_str_has_field (structure, fieldname)) gst_structure_id_str_set_value (structure, fieldname, value); return TRUE; } static gboolean gst_validate_ssim_init (GstPlugin * plugin) { GList *tmp, *config; GstStructure *config_structure = NULL; if (!gst_validate_is_initialized ()) return FALSE; config = gst_validate_plugin_get_config (plugin); for (tmp = config; tmp; tmp = tmp->next) { gboolean is_config; if (gst_structure_get_boolean (tmp->data, "is-config", &is_config)) { if (is_config) { config_structure = tmp->data; break; } } } for (tmp = config; tmp; tmp = tmp->next) { const gchar *name = gst_structure_get_string (tmp->data, "element-name"); const gchar *target_element_classification = gst_structure_get_string (tmp->data, "element-classification"); if (tmp->data == config_structure) continue; if (config_structure) { gst_structure_map_in_place_id_str (config_structure, (GstStructureMapIdStrFunc) _map_confg, tmp->data); } if ((name || target_element_classification)) { GstValidateOverride *override = GST_VALIDATE_OVERRIDE (validate_ssim_override_new (tmp->data)); if (override == NULL) { GST_ERROR ("Could not create override with config %" GST_PTR_FORMAT, tmp->data); continue; } override->buffer_probe_handler = (GstValidateOverrideBufferHandler) _handle_buffer; override->buffer_handler = (GstValidateOverrideBufferHandler) _handle_buffer; override->event_handler = (GstValidateOverrideEventHandler) _handle_event; if (target_element_classification) gst_validate_override_register_by_klass (target_element_classification, override); else if (name) gst_validate_override_register_by_name (name, override); else g_assert_not_reached (); g_object_unref (override); } else { GST_ERROR ("Wrong configuration '%" GST_PTR_FORMAT "'element-classification' and output-dir are mandatory fields", tmp->data); g_assert_not_reached (); } } return TRUE; } GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR, validatessim, "GstValidate plugin to run the ssim algorithm on raw" " video buffers. It allows you to generate png files" "\n " " and then check them against pre generated, reference images." "\n " " The following parameters can be passed in the configuration file:" "\n " " 'element-classification': The target element classification as define in gst_element_class_set_metadata" "\n " " 'output-dir': The directory in which the image files will be saved'" "\n", gst_validate_ssim_init, VERSION, "LGPL", GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)