Speech truncated when piping output

[steinbro]

When I try to generate speech piped directly to aplay, the audio ends prematurely.

For example, when I generate a .wav file and then play it back, I hear the full input tongue twister:

$ echo "Fuzzy Wuzzy was a bear. Fuzzy Wuzzy had no hair. Fuzzy Wuzzy wasn’t fuzzy, was he?" \
    | piper --model en_US-ryan-low.onnx > test.wav 
WARNING:piper.voice:Missing phoneme from id map: ̩

$ aplay test.wav
Playing WAVE 'foo.wav' : Signed 16 bit Little Endian, Rate 16000 Hz, Mono

But if I try to pipe directly to aplay without generating a .wav, The audio stops after "has no hair", and I get a traceback

$ echo "Fuzzy Wuzzy was a bear. Fuzzy Wuzzy had no hair. Fuzzy Wuzzy wasn’t fuzzy, was he?" \
    | piper --model en_US-ryan-low.onnx \
    | aplay -r 16000 -f S16_LE -t raw -
Playing raw data 'stdin' : Signed 16 bit Little Endian, Rate 16000 Hz, Mono
Traceback (most recent call last):
  File "/home/steinbro/.local/share/uv/tools/piper-tts/lib/python3.11/site-packages/piper/__main__.py", line 151, in main
    voice.synthesize(text, wav_file, **synthesize_args)
  File "/home/steinbro/.local/share/uv/tools/piper-tts/lib/python3.11/site-packages/piper/voice.py", line 103, in synthesize
    wav_file.writeframes(audio_bytes)
  File "/home/steinbro/.local/share/uv/python/cpython-3.11.12-linux-aarch64-gnu/lib/python3.11/wave.py", line 560, in writeframes
    self._patchheader()
  File "/home/steinbro/.local/share/uv/python/cpython-3.11.12-linux-aarch64-gnu/lib/python3.11/wave.py", line 615, in _patchheader
    curpos = self._file.tell()
             ^^^^^^^^^^^^^^^^^
OSError: [Errno 29] Illegal seek

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/steinbro/.local/bin/piper", line 10, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/steinbro/.local/share/uv/tools/piper-tts/lib/python3.11/site-packages/piper/__main__.py", line 150, in main
    with wave.open(sys.stdout.buffer, "wb") as wav_file:
  File "/home/steinbro/.local/share/uv/python/cpython-3.11.12-linux-aarch64-gnu/lib/python3.11/wave.py", line 453, in __exit__
    self.close()
  File "/home/steinbro/.local/share/uv/python/cpython-3.11.12-linux-aarch64-gnu/lib/python3.11/wave.py", line 567, in close
    self._patchheader()
  File "/home/steinbro/.local/share/uv/python/cpython-3.11.12-linux-aarch64-gnu/lib/python3.11/wave.py", line 615, in _patchheader
    curpos = self._file.tell()
             ^^^^^^^^^^^^^^^^^
OSError: [Errno 29] Illegal seek