Cleanup subtitle related code and make it easier to use SubMaker (#329)

Also don't output subtitles to STDERR by default.

Signed-off-by: rany <rany2@riseup.net>

examples/streaming_with_subtitles.py

@@ -26,7 +26,7 @@ async def amain() -> None:
             if chunk["type"] == "audio":
                 file.write(chunk["data"])
             elif chunk["type"] == "WordBoundary":
-                submaker.add_cue((chunk["offset"], chunk["duration"]), chunk["text"])
+                submaker.feed(chunk)
 
     with open(SRT_FILE, "w", encoding="utf-8") as file:
         file.write(submaker.get_srt())

src/edge_tts/submaker.py

@@ -1,9 +1,11 @@
 """SubMaker module is used to generate subtitles from WordBoundary events."""
 
-from typing import List, Tuple
+from typing import List
 
 import srt  # type: ignore
 
+from .typing import TTSChunk
+
 
 class SubMaker:
     """
@@ -13,23 +15,25 @@ class SubMaker:
     def __init__(self) -> None:
         self.cues: List[srt.Subtitle] = []  # type: ignore
 
-    def add_cue(self, timestamp: Tuple[float, float], text: str) -> None:
+    def feed(self, msg: TTSChunk) -> None:
         """
-        Add a cue to the SubMaker object.
+        Feed a WordBoundary message to the SubMaker object.
 
         Args:
-            timestamp (tuple): The offset and duration of the subtitle.
-            text (str): The text of the subtitle.
+            msg (dict): The WordBoundary message.
 
         Returns:
             None
         """
+        if msg["type"] != "WordBoundary":
+            raise ValueError("Invalid message type, expected 'WordBoundary'")
+
         self.cues.append(
             srt.Subtitle(
                 index=len(self.cues) + 1,
-                start=srt.timedelta(microseconds=timestamp[0] / 10),
-                end=srt.timedelta(microseconds=sum(timestamp) / 10),
-                content=text,
+                start=srt.timedelta(microseconds=msg["duration"] / 10),
+                end=srt.timedelta(microseconds=(msg["duration"] + msg["offset"]) / 10),
+                content=msg["text"],
             )
         )
 
@@ -41,3 +45,6 @@ class SubMaker:
             str: The SRT formatted subtitles.
         """
         return srt.compose(self.cues)  # type: ignore
+
+    def __str__(self) -> str:
+        return self.get_srt()

src/edge_tts/util.py

@@ -3,8 +3,7 @@
 import argparse
 import asyncio
 import sys
-from io import TextIOWrapper
-from typing import Any, TextIO, Union
+from typing import Any, Optional, TextIO
 
 from tabulate import tabulate
 
@@ -45,31 +44,42 @@ async def _run_tts(args: Any) -> None:
         print("\nOperation canceled.", file=sys.stderr)
         return
 
-    tts: Communicate = Communicate(
+    communicate = Communicate(
         args.text,
         args.voice,
-        proxy=args.proxy,
         rate=args.rate,
         volume=args.volume,
         pitch=args.pitch,
+        proxy=args.proxy,
     )
-    subs: SubMaker = SubMaker()
-    with (
-        open(args.write_media, "wb") if args.write_media else sys.stdout.buffer
-    ) as audio_file:
-        async for chunk in tts.stream():
+    submaker = SubMaker()
+    try:
+        audio_file = (
+            open(args.write_media, "wb")
+            if args.write_media is not None and args.write_media != "-"
+            else sys.stdout.buffer
+        )
+        sub_file: Optional[TextIO] = (
+            open(args.write_subtitles, "w", encoding="utf-8")
+            if args.write_subtitles is not None and args.write_subtitles != "-"
+            else None
+        )
+        if sub_file is None and args.write_subtitles == "-":
+            sub_file = sys.stderr
+
+        async for chunk in communicate.stream():
             if chunk["type"] == "audio":
                 audio_file.write(chunk["data"])
             elif chunk["type"] == "WordBoundary":
-                subs.add_cue((chunk["offset"], chunk["duration"]), chunk["text"])
+                submaker.feed(chunk)
 
-    sub_file: Union[TextIOWrapper, TextIO] = (
-        open(args.write_subtitles, "w", encoding="utf-8")
-        if args.write_subtitles
-        else sys.stderr
-    )
-    with sub_file:
-        sub_file.write(subs.get_srt())
+        if sub_file is not None:
+            sub_file.write(submaker.get_srt())
+    finally:
+        if audio_file is not sys.stdout.buffer:
+            audio_file.close()
+        if sub_file is not None and sub_file is not sys.stderr:
+            sub_file.close()
 
 
 async def amain() -> None: