validate: Add a scrub_backward_seeking scenario

+ Make use of it in ges-launch and do not try to seek while playing in
GES as it is not supported yet

validate/data/Makefile.am

@@ -9,6 +9,7 @@ scenarios_DATA = simple_seeks.scenario \
                  alternate_fast_backward_forward.scenario \
                  pause_resume.scenario \
                  scrub_forward_seeking.scenario \
+                 scrub_backward_seeking.scenario \
                  adaptive_video_size.scenario \
                  adaptive_video_framerate.scenario \
                  adaptive_video_framerate_size.scenario\
@@ -31,6 +32,7 @@ EXTRA_DIST = simple_seeks.scenario \
              alternate_fast_backward_forward.scenario \
              pause_resume.scenario \
              scrub_forward_seeking.scenario \
+             scrub_backward_seeking.scenario \
              adaptive_video_size.scenario \
              adaptive_video_framerate.scenario \
              adaptive_video_framerate_size.scenario\

validate/data/scrub_backward_seeking.scenario

@@ -0,0 +1,7 @@
+description, seek=true
+pause, playback_time=0.0
+seek, playback_time=0.0, start="duration - 0.5", flags=accurate+flush
+seek, playback_time=0.0, start=position-0.1, repeat="min(10, (duration - 0.6))/0.1", flags=accurate+flush
+play, playback_time=0.0
+stop, playback_time=1.0
+

validate/tools/launcher/apps/ges-launch.py

@@ -225,9 +225,8 @@ Available options:""")
                     projects.append(proj)
 
         SCENARIOS = ["play_15s",
-                     "seek_forward",
-                     "seek_backward",
-                     "scrub_forward_seeking"]
+                     "scrub_forward_seeking",
+                     "scrub_backward_seeking"]
         for proj in projects:
             # First playback casses
             for scenario_name in SCENARIOS: