fix: Originalsprache bei Videos mit KI-synchronisierten Tonspuren

Gefunden mit einem englischen Video (0LmCveTM788): ohne -l wurde Arabisch
gewählt, denn jede der 20 Synchron-Tonspuren hat eine eigene „-orig“-Spur.
- original_language(): aus „language“, sonst Tonspur mit „original“, sonst
  die einzige „-orig“-Spur
- Automatische Untertitel nur in der Originalsprache (keine Synchronisation)
- Sprachen auch mit Region: „en“ findet manuelle Untertitel „en-US“

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -87,6 +87,12 @@ Automatische Untertitel ohne `-orig` sind Maschinenübersetzungen aus einer ande
 Sprache und werden nie genommen. Gibt es keine passende Spur, nennt das Skript die
 vorhandenen Sprachen.
 
+Videos mit KI-synchronisierten Tonspuren haben für *jede* Synchronsprache eine
+`-orig`-Spur. Die Originalsprache kommt deshalb aus den Video-Infos (`language`, sonst
+die Tonspur mit dem Vermerk „original“); automatische Untertitel anderer Sprachen
+gehören zur Synchronisation und werden nicht genommen. Sprachen werden auch mit
+Region gefunden: `-l en` findet manuelle Untertitel `en-US`.
+
 ```bash
 ./yt_untertitel.py -u URL                          # → <Video-ID>.de-orig.vtt
 ./yt_untertitel.py -u URL -n Lahnstein -d testdaten # → testdaten/Lahnstein.de-orig.vtt

tests/test_extract_text.py

@@ -46,6 +46,19 @@ def test_default_language_is_original_audio(fake_yt_dlp, tmp_path, monkeypatch,
     assert [p.name for p in tmp_path.iterdir()] == ["output.txt"]
 
 
+def test_default_language_ignores_dubbed_tracks(fake_yt_dlp, tmp_path, monkeypatch):
+    info = {
+        "id": "dub", "language": "en-US", "subtitles": {"en-US": []},
+        "automatic_captions": {"ar-orig": [], "en-orig": []},
+    }
+    run = fake_yt_dlp(info, vtt=VTT)
+    monkeypatch.setattr(yt.subprocess, "run", run)
+    run_main(monkeypatch, "-u", URL, "-o", tmp_path / "out.txt")
+    download = run.calls[1]
+    assert download[download.index("--sub-langs") + 1] == "en-US"
+    assert "--write-subs" in download
+
+
 def test_fliesstext(fake_yt_dlp, tmp_path, monkeypatch, capsys):
     long_vtt = "WEBVTT\n\n" + "".join(
         f"00:00:{i:02d}.000 --> 00:00:{i + 1:02d}.000\nSatz Nummer {i} zum EU-Gipfel.\n\n"

tests/test_yt_untertitel.py

@@ -47,6 +47,49 @@ def test_original_language(info, expected):
     assert yt.original_language(info) == expected
 
 
+# English original with AI-dubbed audio tracks: every dub has its own "-orig"
+DUBBED = {
+    "id": "dub",
+    "language": "en-US",
+    "subtitles": {"en-US": []},
+    "automatic_captions": {"ar-orig": [], "en-orig": [], "de-DE-orig": [], "de": []},
+}
+DUBBED_NO_METADATA = {
+    "formats": [
+        {"format_note": "Arabic, low", "language": "ar"},
+        {"format_note": "English (US) original (default), low", "language": "en-US"},
+    ],
+    "subtitles": {},
+    "automatic_captions": {"ar-orig": [], "en-orig": [], "de-DE-orig": []},
+}
+
+
+@pytest.mark.parametrize("info, lang, expected", [
+    (DUBBED, "en", ("en-US", False)),          # region variant of a manual track
+    (DUBBED, "en-US", ("en-US", False)),
+    (DUBBED, "de", None),                      # only the German AI dub
+    (DUBBED, "ar", None),
+    (DUBBED_NO_METADATA, "en-US", ("en-orig", True)),
+    (DUBBED_NO_METADATA, "en", ("en-orig", True)),
+    (DUBBED_NO_METADATA, "de", None),
+])
+def test_choose_track_with_dubbed_audio(info, lang, expected):
+    assert yt.choose_track(info, lang) == expected
+
+
+@pytest.mark.parametrize("info, expected", [
+    (DUBBED, "en-US"),
+    (DUBBED_NO_METADATA, "en-US"),             # from the audio track marked original
+    ({"automatic_captions": {"ar-orig": [], "en-orig": []}}, None),
+])
+def test_original_language_with_dubbed_audio(info, expected):
+    assert yt.original_language(info) == expected
+
+
+def test_available_tracks_hides_dubs():
+    assert yt.available_tracks(DUBBED) == (["en-US"], ["en"])
+
+
 def test_available_tracks():
     info = {"subtitles": {"fr": []}, "automatic_captions": {"de-orig": [], "de": []}}
     assert yt.available_tracks(info) == (["fr"], ["de"])

yt_untertitel.py

@@ -31,39 +31,66 @@ def fetch_info(url):
     return json.loads(result.stdout)
 
 
-def choose_track(info, lang):
-    """Pick the subtitle track for `lang`: (track name, is_auto) or None.
-
-    Manual subtitles come first. Of the automatic captions only the original
-    language ("<lang>-orig") is used: plain "<lang>" there is a machine
-    translation whenever the video is in another language.
-    """
-    if lang in (info.get("subtitles") or {}):
-        return lang, False
-    if f"{lang}-orig" in (info.get("automatic_captions") or {}):
-        return f"{lang}-orig", True
-    return None
+def base_language(code):
+    """"en-US" -> "en", "de-orig" -> "de"."""
+    return code.removesuffix("-orig").split("-")[0].lower()
 
 
 def original_language(info):
-    """Language of the video's audio, or None if yt-dlp does not know it.
+    """Language of the video's original audio, or None if unknown.
 
-    YouTube marks the automatic captions in the spoken language with "-orig".
+    Not simply the first "<lang>-orig" caption track: videos with AI-dubbed
+    audio tracks have such a track for every dubbed language.
     """
-    for name in info.get("automatic_captions") or {}:
-        if name.endswith("-orig"):
-            return name.removesuffix("-orig")
-    return info.get("language")
+    if info.get("language"):
+        return info["language"]
+    for fmt in info.get("formats") or []:
+        if "original" in (fmt.get("format_note") or "") and fmt.get("language"):
+            return fmt["language"]
+    originals = [n for n in info.get("automatic_captions") or {} if n.endswith("-orig")]
+    return originals[0].removesuffix("-orig") if len(originals) == 1 else None
+
+
+def choose_track(info, lang):
+    """Pick the subtitle track for `lang`: (track name, is_auto) or None.
+
+    Manual subtitles come first, also with a region ("en" finds "en-US").
+    Automatic captions are used only in the language of the original audio
+    ("<lang>-orig"): plain "<lang>" is a machine translation, and "-orig"
+    tracks of other languages belong to AI-dubbed audio tracks.
+    """
+    manual = info.get("subtitles") or {}
+    if lang in manual:
+        return lang, False
+    same_language = sorted(n for n in manual if base_language(n) == base_language(lang))
+    if same_language:
+        return same_language[0], False
+
+    original = original_language(info)
+    if original and base_language(original) != base_language(lang):
+        return None
+    auto = info.get("automatic_captions") or {}
+    candidates = [f"{lang}-orig", f"{base_language(lang)}-orig"] + sorted(
+        n for n in auto
+        if n.endswith("-orig") and base_language(n) == base_language(lang)
+    )
+    for name in candidates:
+        if name in auto:
+            return name, True
+    return None
 
 
 def available_tracks(info):
+    """Manual tracks and the automatic ones usable for this program."""
     manual = sorted((info.get("subtitles") or {}).keys())
-    original = sorted(
+    original = original_language(info)
+    automatic = sorted(
         name.removesuffix("-orig")
         for name in (info.get("automatic_captions") or {})
         if name.endswith("-orig")
+        and (original is None or base_language(name) == base_language(original))
     )
-    return manual, original
+    return manual, automatic
 
 
 def no_track_message(info, lang):