Drop words_in_cue code for SubMaker and switch to SRT (#323)

WebVTT isn't a very common format in the first place
and attempting to make WordBoundary play nice with
input text is very hard.

Instead we now just display the word that the TTS
is saying at a given time. In the future, we could
try to enable SentenceBoundary but there is a risk
that it will be banned by Microsoft as it is not used
by Microsoft Edge itself.

Closes: https://github.com/rany2/edge-tts/issues/118
Closes: https://github.com/rany2/edge-tts/issues/171
Closes: https://github.com/rany2/edge-tts/issues/229
Closes: https://github.com/rany2/edge-tts/issues/234

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

src/edge_tts/util.py

@@ -61,7 +61,7 @@ async def _run_tts(args: Any) -> None:
             if chunk["type"] == "audio":
                 audio_file.write(chunk["data"])
             elif chunk["type"] == "WordBoundary":
-                subs.create_sub((chunk["offset"], chunk["duration"]), chunk["text"])
+                subs.add_cue((chunk["offset"], chunk["duration"]), chunk["text"])
 
     sub_file: Union[TextIOWrapper, TextIO] = (
         open(args.write_subtitles, "w", encoding="utf-8")
@@ -69,7 +69,7 @@ async def _run_tts(args: Any) -> None:
         else sys.stderr
     )
     with sub_file:
-        sub_file.write(subs.generate_subs(args.words_in_cue))
+        sub_file.write(subs.get_srt())
 
 
 async def amain() -> None:
@@ -93,12 +93,6 @@ async def amain() -> None:
     parser.add_argument("--rate", help="set TTS rate. Default +0%%.", default="+0%")
     parser.add_argument("--volume", help="set TTS volume. Default +0%%.", default="+0%")
     parser.add_argument("--pitch", help="set TTS pitch. Default +0Hz.", default="+0Hz")
-    parser.add_argument(
-        "--words-in-cue",
-        help="number of words in a subtitle cue. Default: 10.",
-        default=10,
-        type=float,
-    )
     parser.add_argument(
         "--write-media", help="send media output to file instead of stdout"
     )