Fix the pytorch tts streaming example. (#84)

* Fix the pytorch tts streaming example.

* Edit the readme too.

README.md

@@ -237,6 +237,14 @@ echo "Hey, how are you?" | python scripts/tts_pytorch.py - -
 python scripts/tts_pytorch.py text_to_say.txt audio_output.wav
 ```
 
+The `tts_pytorch.py` script waits for all the text to be available before
+starting the audio generation. A fully streaming implementation is available in
+the `tts_pytorch_streaming.py` script, which can be used as follows:
+
+```bash
+echo "Hey, how are you?" | python scripts/tts_pytorch_streaming.py audio_output.wav
+```
+
 This requires the [moshi package](https://pypi.org/project/moshi/), which can be installed via pip.
 If you have [uv](https://docs.astral.sh/uv/) installed, you can skip the installation step
 and just prefix the command above with `uvx --with moshi`.

scripts/tts_pytorch_streaming.py

@@ -21,10 +21,24 @@ from moshi.models.loaders import CheckpointInfo
 from moshi.conditioners import dropout_all_conditions
 from moshi.models.lm import LMGen
 from moshi.models.tts import (
+    Entry,
     DEFAULT_DSM_TTS_REPO,
     DEFAULT_DSM_TTS_VOICE_REPO,
     TTSModel,
     ConditionAttributes,
+    script_to_entries,
+)
+
+
+def prepare_script(model: TTSModel, script: str, first_turn: bool) -> list[Entry]:
+    multi_speaker = first_turn and model.multi_speaker
+    return script_to_entries(
+        model.tokenizer,
+        model.machine.token_ids,
+        model.mimi.frame_rate,
+        [script],
+        multi_speaker=multi_speaker,
+        padding_between=1,
     )
 
 
@@ -206,9 +220,10 @@ def main():
             channels=1,
             callback=audio_callback,
         ) and tts_model.mimi.streaming(1):
+            first_turn = True
             for line in sys.stdin:
-                # TODO: Fix the following to only include bos on the first line.
-                entries = tts_model.prepare_script([line.strip()], padding_between=1)
+                entries = prepare_script(tts_model, line.strip(), first_turn=first_turn)
+                first_turn = False
                 for entry in entries:
                     gen.append_entry(entry)
                     gen.process()
@@ -227,9 +242,10 @@ def main():
 
         gen = TTSGen(tts_model, [condition_attributes], on_frame=_on_frame)
         with tts_model.mimi.streaming(1):
+            first_turn = True
             for line in sys.stdin:
-                # TODO: Fix the following to only include bos on the first line.
-                entries = tts_model.prepare_script([line.strip()], padding_between=1)
+                entries = prepare_script(tts_model, line.strip(), first_turn=first_turn)
+                first_turn = False
                 for entry in entries:
                     gen.append_entry(entry)
                     gen.process()