[pitivi/wip-speed-control: 2/2] pipeline: Use GES frame APIs to do frame stepping

[Alexandru Băluț <alexbalut src gnome org>]

commit 043e5ead40e320671c8b8b65df2bf64a6ad39e70
Author: Thibault Saunier <tsaunier igalia com>
Date:   Wed May 27 18:42:56 2020 -0400

    pipeline: Use GES frame APIs to do frame stepping

 pitivi/timeline/timeline.py |  4 ++--
 pitivi/utils/pipeline.py    | 18 ++++++------------
 2 files changed, 8 insertions(+), 14 deletions(-)
---
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index 930474ad1..e22d5e5d2 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -2174,12 +2174,12 @@ class TimelineContainer(Gtk.Grid, Zoomable, Loggable):
         self.timeline.scroll_to_playhead(align=Gtk.Align.CENTER, when_not_in_view=True)
 
     def _seek_backward_one_frame_cb(self, unused_action, unused_parameter):
-        self._project.pipeline.step_frame(self._project.videorate, -1)
+        self._project.pipeline.step_frame(-1)
         self.timeline.scroll_to_playhead(align=Gtk.Align.CENTER, when_not_in_view=True)
 
     def _seek_forward_one_frame_cb(self, unused_action, unused_parameter):
 
-        self._project.pipeline.step_frame(self._project.videorate, 1)
+        self._project.pipeline.step_frame(1)
         self.timeline.scroll_to_playhead(align=Gtk.Align.CENTER, when_not_in_view=True)
 
     def do_focus_in_event(self, unused_event):
diff --git a/pitivi/utils/pipeline.py b/pitivi/utils/pipeline.py
index d389ba906..08078ed39 100644
--- a/pitivi/utils/pipeline.py
+++ b/pitivi/utils/pipeline.py
@@ -577,13 +577,12 @@ class Pipeline(GES.Pipeline, SimplePipeline):
 
         return GES.Pipeline.do_change_state(self, state)
 
-    def step_frame(self, framerate, frames_offset):
+    def step_frame(self, frames_offset):
         """Seeks backwards or forwards the specified amount of frames.
 
         This clamps the playhead to the project frames.
 
         Args:
-            framerate (Gst.Fraction): The framerate of the project.
             frames_offset (int): The number of frames to step. Negative number
                 for stepping backwards.
         """
@@ -594,16 +593,11 @@ class Pipeline(GES.Pipeline, SimplePipeline):
                 "Couldn't get position (you're framestepping too quickly), ignoring this request")
             return
 
-        cur_frame = int(
-            round(position * framerate.num / float(Gst.SECOND * framerate.denom), 2))
-        new_frame = cur_frame + frames_offset
-        new_pos = int(new_frame * Gst.SECOND * framerate.denom / framerate.num) + \
-            int((Gst.SECOND * framerate.denom / framerate.num) / 2)
-        Loggable.info(self, "From frame %d to %d at %f fps, seek to %s s",
-                      cur_frame,
-                      new_frame,
-                      framerate.num / framerate.denom,
-                      new_pos / float(Gst.SECOND))
+        cur_frame = self.props.timeline.get_frame_at(position)
+        new_frame = max(0, cur_frame + frames_offset)
+        new_pos = self.props.timeline.get_frame_time(new_frame)
+        self.info("From frame %d to %d - seek to %s",
+                  cur_frame, new_frame, new_pos)
         self.simple_seek(new_pos)
 
     def simple_seek(self, position):