🐞 Fix slides scaling (#1)

bbbdl/__main__.py

@@ -30,13 +30,13 @@ def download(input_url, output_file, overwrite=False, verbose_ffmpeg=False, debu
     meeting = Meeting.from_url(input_url)
 
     click.secho(f"Downloading: {input_url} -> {output_file}", err=True, fg="green")
-    streams = compose_lesson(meeting)
+    tracks = compose_lesson(meeting, 1280, 720)
 
-    output = ffmpeg.output(*streams, output_file)
+    output = ffmpeg.output(tracks.video, tracks.audio, output_file)
 
     if debug:
         click.echo(" ".join(output.compile()))
-    else:
+
     output.run(quiet=not verbose_ffmpeg, overwrite_output=True)
 
 

bbbdl/composer.py

@@ -1,24 +1,30 @@
 from typing import *
 import ffmpeg
 from .resources import Meeting
+from .tracks import Tracks
 
 
-def compose_screensharing(meeting: Meeting) -> Tuple[ffmpeg.Stream, ffmpeg.Stream]:
-    """Keep the deskshare video and the webcam audio, while discarding the rest."""
+def compose_screensharing(meeting: Meeting, width: int, height: int) -> Tracks:
+    tracks = Tracks()
 
-    return (
-        meeting.deskshare.as_stream().video,
-        meeting.webcams.as_stream().audio,
-    )
+    if meeting.webcams:
+        tracks.overlay(meeting.webcams.get_video().filter("scale", width, height).filter("setsar", 1, 1))
+        tracks.amerge(meeting.webcams.get_audio())
+
+    if meeting.deskshare:
+        tracks.overlay(meeting.deskshare.get_video().filter("scale", width, height).filter("setsar", 1, 1))
+
+    return tracks
 
 
-def compose_lesson(meeting: Meeting) -> Tuple[ffmpeg.Stream, ffmpeg.Stream]:
-    """Keep slides, deskshare video and webcam audio, while discarding the rest."""
-
-    video_stream, audio_stream = compose_screensharing(meeting)
+def compose_lesson(meeting: Meeting, width: int, height: int) -> Tracks:
+    tracks = compose_screensharing(meeting, width, height)
 
     for shape in meeting.shapes:
-        video_stream = ffmpeg.overlay(video_stream, shape.resource.as_stream().video.filter("scale", 1280, 720),
-                                      enable=f"between(t, {shape.start}, {shape.end})")
+        scaled_split_shape = shape.resource.get_video().filter("scale", width, height).filter("setsar", 1, 1).split()
+        count = 0
+        for enable in shape.enables:
+            count += 1
+            tracks.overlay(scaled_split_shape.stream(count), enable=f"between(t, {enable[0]}, {enable[1]})")
 
-    return video_stream, audio_stream
+    return tracks

bbbdl/resources.py

@@ -7,35 +7,42 @@ import ffmpeg
 from .urlhandler import playback_to_data
 
 
-@dataclasses.dataclass()
 class Resource:
-    href: str
+    def __init__(self, href: str):
+        self.href: str = href
+        self._video: Optional[ffmpeg.Stream] = None
+        self._video_count: int = 0
+        self._audio: Optional[ffmpeg.Stream] = None
+        self._audio_count: int = 0
 
-    def as_stream(self, **kwargs) -> ffmpeg.Stream:
-        return ffmpeg.input(self.href, **kwargs)
+    def __repr__(self):
+        return f"<{self.__class__.__qualname__} href={self.href}>"
+
+    @classmethod
+    def check_and_create(cls, href: str) -> Optional[Resource]:
+        """Check if the resource exists, and create it if it does."""
+        r = requests.head(href)
+        if not (200 <= r.status_code < 400):
+            return None
+        return cls(href=href)
+
+    def get_audio(self) -> ffmpeg.nodes.FilterableStream:
+        if self._audio is None:
+            self._audio = ffmpeg.input(self.href).audio.asplit()
+        self._audio_count += 1
+        return self._audio.stream(self._audio_count)
+
+    def get_video(self) -> ffmpeg.nodes.FilterableStream:
+        if self._video is None:
+            self._video = ffmpeg.input(self.href).video.split()
+        self._video_count += 1
+        return self._video.stream(self._video_count)
 
 
 @dataclasses.dataclass()
 class Shape:
     resource: Resource
-    start: float
-    end: float
-
-    @classmethod
-    def from_tag(cls, tag: bs4.Tag, *, base_url: str) -> Shape:
-        # No, `"in" not in tag` does not work
-        if not tag["in"]:
-            raise ValueError("Tag has no 'in' parameter")
-        if not tag["out"]:
-            raise ValueError("Tag has no 'out' parameter")
-        if not tag["xlink:href"]:
-            raise ValueError("Tag has no 'xlink:href' parameter")
-
-        return cls(
-            resource=Resource(href=f"{base_url}/{tag['xlink:href']}"),
-            start=float(tag["in"]),
-            end=float(tag["out"]),
-        )
+    enables: List[Tuple[float, float]]
 
 
 @dataclasses.dataclass()
@@ -49,22 +56,30 @@ class Meeting:
         r = requests.get(f"{base_url}/presentation/{meeting_id}/metadata.xml")
         r.raise_for_status()
 
-        deskshare = Resource(href=f"{base_url}/presentation/{meeting_id}/deskshare/deskshare.webm")
-        webcams = Resource(href=f"{base_url}/presentation/{meeting_id}/video/webcams.mp4")
+        deskshare = Resource.check_and_create(href=f"{base_url}/presentation/{meeting_id}/deskshare/deskshare.mp4")
+        webcams = Resource.check_and_create(href=f"{base_url}/presentation/{meeting_id}/video/webcams.mp4")
 
         shape_soup = bs4.BeautifulSoup(requests.get(f"{base_url}/presentation/{meeting_id}/shapes.svg").text,
                                        "lxml")
-        shapes: List[Shape] = []
+
+        shapes: Dict[str, Shape] = {}
         for tag in shape_soup.find_all("image"):
-            try:
-                shapes.append(Shape.from_tag(tag, base_url=f"{base_url}/presentation/{meeting_id}"))
-            except ValueError:
-                continue
+            if not tag["in"]:
+                raise ValueError("Tag has no 'in' parameter")
+            if not tag["out"]:
+                raise ValueError("Tag has no 'out' parameter")
+            if not tag["xlink:href"]:
+                raise ValueError("Tag has no 'xlink:href' parameter")
+
+            url = tag["xlink:href"]
+            if url not in shapes:
+                shapes[url] = Shape(resource=Resource(f"{base_url}/presentation/{meeting_id}/{url}"), enables=[])
+            shapes[url].enables.append((tag["in"], tag["out"]))
 
         return cls(
             deskshare=deskshare,
             webcams=webcams,
-            shapes=shapes
+            shapes=list(shapes.values())
         )
 
     @classmethod

bbbdl/tracks.py

@@ -0,0 +1,20 @@
+from typing import Optional
+import ffmpeg.nodes
+
+
+class Tracks:
+    def __init__(self):
+        self.video: Optional[ffmpeg.nodes.FilterableStream] = None
+        self.audio: Optional[ffmpeg.nodes.FilterableStream] = None
+
+    def overlay(self, other: ffmpeg.nodes.FilterableStream, **kwargs):
+        if self.video is None:
+            self.video = other
+        else:
+            self.video = self.video.overlay(other, **kwargs)
+
+    def amerge(self, other: ffmpeg.nodes.FilterableStream, **kwargs):
+        if self.audio is None:
+            self.audio = other
+        else:
+            self.audio = ffmpeg.filter((self.audio, other), "amerge", **kwargs)