initial commit and version 1.0

moviepy/video/io/ffplay_previewer.py

@@ -0,0 +1,137 @@
+"""
+On the long term this will implement several methods to make videos
+out of VideoClips
+"""
+
+import subprocess as sp
+
+from moviepy.config import FFPLAY_BINARY
+from moviepy.tools import cross_platform_popen_params
+
+
+class FFPLAY_VideoPreviewer:
+    """A class for FFPLAY-based video preview.
+
+    Parameters
+    ----------
+
+    size : tuple or list
+      Size of the output video in pixels (width, height).
+
+    fps : int
+      Frames per second in the output video file.
+
+    pixel_format : str
+      Pixel format for the output video file, ``rgb24`` for normal video, ``rgba``
+      if video with mask.
+    """
+
+    def __init__(
+        self,
+        size,
+        fps,
+        pixel_format,
+    ):
+        # order is important
+        cmd = [
+            FFPLAY_BINARY,
+            "-autoexit",  # If you don't precise, ffplay won't stop at end
+            "-f",
+            "rawvideo",
+            "-pixel_format",
+            pixel_format,
+            "-video_size",
+            "%dx%d" % (size[0], size[1]),
+            "-framerate",
+            "%.02f" % fps,
+            "-",
+        ]
+
+        popen_params = cross_platform_popen_params(
+            {"stdout": sp.DEVNULL, "stderr": sp.STDOUT, "stdin": sp.PIPE}
+        )
+
+        self.proc = sp.Popen(cmd, **popen_params)
+
+    def show_frame(self, img_array):
+        """Writes one frame in the file."""
+        try:
+            self.proc.stdin.write(img_array.tobytes())
+        except IOError as err:
+            _, ffplay_error = self.proc.communicate()
+            if ffplay_error is not None:
+                ffplay_error = ffplay_error.decode()
+
+            error = (
+                f"{err}\n\nMoviePy error: FFPLAY encountered the following error while "
+                f"previewing clip :\n\n {ffplay_error}"
+            )
+
+            raise IOError(error)
+
+    def close(self):
+        """Closes the writer, terminating the subprocess if is still alive."""
+        if self.proc:
+            self.proc.stdin.close()
+            if self.proc.stderr is not None:
+                self.proc.stderr.close()
+            self.proc.wait()
+
+            self.proc = None
+
+    # Support the Context Manager protocol, to ensure that resources are cleaned up.
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.close()
+
+
+def ffplay_preview_video(
+    clip, fps, pixel_format="rgb24", audio_flag=None, video_flag=None
+):
+    """Preview the clip using ffplay. See VideoClip.preview for details
+    on the parameters.
+
+    Parameters
+    ----------
+
+    clip : VideoClip
+      The clip to preview
+
+    fps : int
+      Number of frames per seconds in the displayed video.
+
+    pixel_format : str, optional
+      Warning: This is not used anywhere in the code and should probably
+      be removed.
+      It is believed pixel format rgb24 does not work properly for now because
+      it requires applying a mask on CompositeVideoClip and that is believed to
+      not be working.
+
+      Pixel format for the output video file, ``rgb24`` for normal video, ``rgba``
+      if video with mask
+
+    audio_flag : Thread.Event, optional
+      A thread event that video will wait for. If not provided we ignore audio
+
+    video_flag : Thread.Event, optional
+      A thread event that video will set after first frame has been shown. If not
+      provided, we simply ignore
+    """
+    with FFPLAY_VideoPreviewer(clip.size, fps, pixel_format) as previewer:
+        first_frame = True
+        for t, frame in clip.iter_frames(with_times=True, fps=fps, dtype="uint8"):
+            previewer.show_frame(frame)
+
+            # After first frame is shown, if we have audio/video flag, set video ready
+            # and wait for audio
+            if first_frame:
+                first_frame = False
+
+                if video_flag:
+                    video_flag.set()  # say to the audio: video is ready
+
+                if audio_flag:
+                    audio_flag.wait()  # wait for the audio to be ready