Merge pull request #4475 from pipecat-ai/mb/cartesia-korean-fix

Fix Cartesia CJK timestamp spacing

tests/test_cartesia_tts.py

@@ -0,0 +1,111 @@
+#
+# Copyright (c) 2024-2026, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+from pipecat.services.cartesia.tts import CartesiaTTSService
+from pipecat.services.settings import TTSSettings
+from pipecat.utils.string import TextPartForConcatenation, concatenate_aggregated_text
+
+
+def _service(language: str) -> CartesiaTTSService:
+    service = CartesiaTTSService.__new__(CartesiaTTSService)
+    service._settings = TTSSettings(language=language)
+    return service
+
+
+def _process_word_timestamps(
+    words: list[str], starts: list[float], language: str
+) -> list[tuple[str, float]]:
+    return _service(language)._process_word_timestamps_for_language(words, starts)
+
+
+def _concatenate_processed_timestamps(
+    timestamp_groups: list[tuple[list[str], list[float]]], language: str
+) -> str:
+    service = _service(language)
+    text_parts = []
+    for words, starts in timestamp_groups:
+        processed_timestamps = service._process_word_timestamps_for_language(words, starts)
+        includes_inter_frame_spaces = service._word_timestamps_include_inter_frame_spaces()
+        text_parts.extend(
+            TextPartForConcatenation(
+                word,
+                includes_inter_part_spaces=includes_inter_frame_spaces,
+            )
+            for word, _timestamp in processed_timestamps
+        )
+    return concatenate_aggregated_text(text_parts)
+
+
+def test_cartesia_chinese_word_timestamps_join_without_spaces():
+    assert _process_word_timestamps(
+        words=["你", "好", "。"],
+        starts=[0.0, 0.1, 0.2],
+        language="zh",
+    ) == [("你好。", 0.0)]
+
+
+def test_cartesia_japanese_word_timestamps_join_without_spaces():
+    assert _process_word_timestamps(
+        words=["こ", "ん", "に", "ち", "は", "。"],
+        starts=[0.0, 0.1, 0.2, 0.3, 0.4, 0.5],
+        language="ja",
+    ) == [("こんにちは。", 0.0)]
+
+
+def test_cartesia_korean_word_timestamps_preserve_words_and_timestamps():
+    assert _process_word_timestamps(
+        words=["안녕하세요", "반갑습니다"],
+        starts=[0.0, 0.2],
+        language="ko",
+    ) == [("안녕하세요", 0.0), ("반갑습니다", 0.2)]
+
+
+def test_cartesia_korean_word_timestamps_do_not_join_latin_and_hangul():
+    assert _process_word_timestamps(
+        words=["AI", "어시스턴트입니다."],
+        starts=[3.7026982, 4.1999383],
+        language="ko",
+    ) == [("AI", 3.7026982), ("어시스턴트입니다.", 4.1999383)]
+
+
+def test_cartesia_japanese_timestamp_groups_reassemble_without_spaces():
+    assert (
+        _concatenate_processed_timestamps(
+            [
+                (["こ", "ん", "に", "ち", "は", "、", "私"], [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7]),
+                (["は", "あ", "な", "た", "の"], [1.0, 1.1, 1.2, 1.3, 1.4]),
+            ],
+            language="ja",
+        )
+        == "こんにちは、私はあなたの"
+    )
+
+
+def test_cartesia_chinese_timestamp_groups_reassemble_without_spaces():
+    assert (
+        _concatenate_processed_timestamps(
+            [
+                (["你", "好", "，", "我", "是"], [0.1, 0.2, 0.3, 0.4, 0.5]),
+                (["你", "的", "智", "能"], [1.0, 1.1, 1.2, 1.3]),
+            ],
+            language="zh",
+        )
+        == "你好，我是你的智能"
+    )
+
+
+def test_cartesia_korean_timestamp_groups_reassemble_with_spaces():
+    assert (
+        _concatenate_processed_timestamps(
+            [
+                (["저는"], [1.6]),
+                (["여러분의"], [1.8]),
+                (["AI", "어시스턴트입니다."], [3.7, 4.2]),
+            ],
+            language="ko",
+        )
+        == "저는 여러분의 AI 어시스턴트입니다."
+    )