diff --git a/src/calibre/gui2/tts/download.py b/src/calibre/gui2/tts/download.py
index 0778351c0e..55ac5b5c41 100644
--- a/src/calibre/gui2/tts/download.py
+++ b/src/calibre/gui2/tts/download.py
@@ -171,9 +171,9 @@ def download_resources(
     from calibre import browser
     print(title)
     print(message)
+    br = browser()
     for url, (path, name) in urls.items():
         print(_('Downloading {}...').format(name))
-        br = browser()
         data = br.open_novisit(url).read()
         with open(path, 'wb') as f:
             f.write(data)
diff --git a/src/calibre/gui2/tts/piper.py b/src/calibre/gui2/tts/piper.py
index 09291e8075..50d67e1104 100644
--- a/src/calibre/gui2/tts/piper.py
+++ b/src/calibre/gui2/tts/piper.py
@@ -9,11 +9,14 @@ import sys
 from collections import deque
 from contextlib import suppress
 from dataclasses import dataclass
+from functools import lru_cache
 from itertools import count
+from queue import Empty, Queue
+from threading import Event
 from time import monotonic
+from typing import BinaryIO, Iterable, Iterator
 
 from qt.core import (
-    QApplication,
     QAudio,
     QAudioFormat,
     QAudioSink,
@@ -32,7 +35,7 @@ from qt.core import (
 
 from calibre.constants import cache_dir, is_debugging, piper_cmdline
 from calibre.gui2 import error_dialog
-from calibre.gui2.tts.types import EngineSpecificSettings, Quality, TTSBackend, Voice, widget_parent
+from calibre.gui2.tts.types import TTS_EMBEDED_CONFIG, EngineSpecificSettings, Quality, TTSBackend, Voice, widget_parent
 from calibre.spell.break_iterator import PARAGRAPH_SEPARATOR, split_into_sentences_for_tts
 from calibre.utils.localization import canonicalize_lang, get_lang
 from calibre.utils.resources import get_path as P
@@ -46,6 +49,97 @@ def debug(*a, **kw):
         print(f'[{monotonic() - debug.first:.2f}]', *a, **kw)
 
 
+def audio_format(audio_rate: int = 22050) -> QAudioFormat:
+    fmt = QAudioFormat()
+    fmt.setSampleFormat(QAudioFormat.SampleFormat.Int16)
+    fmt.setSampleRate(audio_rate)
+    fmt.setChannelConfig(QAudioFormat.ChannelConfig.ChannelConfigMono)
+    return fmt
+
+
+def piper_process_metadata(model_path, config_path, s: EngineSpecificSettings, voice: Voice) -> tuple[int, list[str]]:
+    if not model_path:
+        raise Exception('Could not download voice data')
+    if 'metadata' not in voice.engine_data:
+        with open(config_path) as f:
+            voice.engine_data['metadata'] = json.load(f)
+    audio_rate = voice.engine_data['metadata']['audio']['sample_rate']
+    length_scale = max(0.1, 1 + -1 * s.rate)  # maps -1 to 1 to 2 to 0.1
+    cmdline = list(piper_cmdline()) + [
+        '--model', model_path, '--config', config_path, '--output-raw', '--json-input',
+        '--sentence-silence', str(s.sentence_delay), '--length_scale', str(length_scale)]
+    if is_debugging():
+        cmdline.append('--debug')
+    return audio_rate, cmdline
+
+
+def piper_cache_dir() -> str:
+    return os.path.join(cache_dir(), 'piper-voices')
+
+
+def paths_for_voice(voice: Voice) -> tuple[str, str]:
+    fname = voice.engine_data['model_filename']
+    model_path = os.path.join(piper_cache_dir(), fname)
+    config_path = os.path.join(os.path.dirname(model_path), fname + '.json')
+    return model_path, config_path
+
+
+def load_voice_metadata() -> tuple[dict[str, Voice], tuple[Voice, ...], dict[str, Voice]]:
+    d = json.loads(P('piper-voices.json', data=True))
+    ans = []
+    lang_voices_map = {}
+    _voice_name_map = {}
+    downloaded = set()
+    with suppress(OSError):
+        downloaded = set(os.listdir(piper_cache_dir()))
+    for bcp_code, voice_map in d['lang_map'].items():
+        lang, sep, country = bcp_code.partition('_')
+        lang = canonicalize_lang(lang) or lang
+        voices_for_lang = lang_voices_map.setdefault(lang, [])
+        for voice_name, qual_map in voice_map.items():
+            best_qual = voice = None
+            for qual, e in qual_map.items():
+                q = Quality.from_piper_quality(qual)
+                if best_qual is None or q.value < best_qual.value:
+                    best_qual = q
+                    mf = f'{bcp_code}-{voice_name}-{qual}.onnx'
+                    voice = Voice(bcp_code + ':' + voice_name, lang, country, human_name=voice_name, quality=q, engine_data={
+                        'model_url': e['model'], 'config_url': e['config'],
+                        'model_filename': mf, 'is_downloaded': mf in downloaded,
+                    })
+            if voice:
+                ans.append(voice)
+                _voice_name_map[voice.name] = voice
+                voices_for_lang.append(voice)
+    _voices = tuple(ans)
+    _voice_for_lang = {}
+    for lang, voices in lang_voices_map.items():
+        voices.sort(key=lambda v: v.quality.value)
+        _voice_for_lang[lang] = voices[0]
+        if lang == 'eng':
+            for v in voices:
+                if v.human_name == 'libritts':
+                    _voice_for_lang[lang] = v
+                    break
+    return _voice_name_map, _voices, _voice_for_lang
+
+
+def download_voice(voice: Voice, download_even_if_exists: bool = False, parent: QObject | None = None, headless: bool = False) -> tuple[str, str]:
+    model_path, config_path = paths_for_voice(voice)
+    if os.path.exists(model_path) and os.path.exists(config_path):
+        if not download_even_if_exists:
+            return model_path, config_path
+    os.makedirs(os.path.dirname(model_path), exist_ok=True)
+    from calibre.gui2.tts.download import download_resources
+    ok = download_resources(_('Downloading voice for Read aloud'), _('Downloading neural network for the {} voice').format(voice.human_name), {
+            voice.engine_data['model_url']: (model_path, _('Neural network data')),
+            voice.engine_data['config_url']: (config_path, _('Neural network metadata')),
+        }, parent=widget_parent(parent), headless=headless,
+    )
+    voice.engine_data['is_downloaded'] = bool(ok)
+    return (model_path, config_path) if ok else ('', '')
+
+
 @dataclass
 class Utterance:
     id: int
@@ -156,13 +250,34 @@ def split_into_utterances(text: str, counter: count, lang: str = 'en'):
         yield u
 
 
+@lru_cache(2)
+def stderr_pat():
+    return re.compile(rb'\[piper\] \[([a-zA-Z0-9_]+?)\] (.+)')
+
+
+def detect_end_of_data(data: bytes, callback):
+    lines = data.split(b'\n')
+    for line in lines[:-1]:
+        if m := stderr_pat().search(line):
+            which, payload = m.group(1), m.group(2)
+            if which == b'info':
+                debug(f'[piper-info] {payload.decode("utf-8", "replace")}')
+                if payload.startswith(b'Real-time factor:'):
+                    callback(True, None)
+            elif which == b'error':
+                callback(False, payload.decode('utf-8', 'replace'))
+            elif which == b'debug':
+                debug(f'[piper-debug] {payload.decode("utf-8", "replace")}')
+    return lines[-1]
+
+
 class Piper(TTSBackend):
 
     engine_name: str = 'piper'
     filler_char: str = PARAGRAPH_SEPARATOR
     _synthesis_done = pyqtSignal()
 
-    def __init__(self, engine_name: str = '', parent: QObject|None = None):
+    def __init__(self, engine_name: str = '', parent: QObject | None = None):
         super().__init__(parent)
         self._process: QProcess | None = None
         self._audio_sink: QAudioSink | None = None
@@ -179,7 +294,6 @@ class Piper(TTSBackend):
         self._errors_from_piper: list[str] = []
         self._pending_stderr_data = b''
 
-        self._stderr_pat = re.compile(rb'\[piper\] \[([a-zA-Z0-9_]+?)\] (.+)')
         self._synthesis_done.connect(self._utterance_synthesized, type=Qt.ConnectionType.QueuedConnection)
         atexit.register(self.shutdown)
 
@@ -188,16 +302,21 @@ class Piper(TTSBackend):
         self._load_voice_metadata()
         return {'': self._voices}
 
-    def say(self, text: str) -> None:
-        if self._last_error:
-            return
-        self.stop()
+    def _wait_for_process_to_start(self) -> bool:
         if not self.process.waitForStarted():
             cmdline = [self.process.program()] + self.process.arguments()
             if self.process.error() is QProcess.ProcessError.TimedOut:
                 self._set_error(f'Timed out waiting for piper process {cmdline} to start')
             else:
                 self._set_error(f'Failed to start piper process: {cmdline}')
+            return False
+        return True
+
+    def say(self, text: str) -> None:
+        if self._last_error:
+            return
+        self.stop()
+        if not self._wait_for_process_to_start():
             return
         lang = 'en'
         if self._current_voice and self._current_voice.language_code:
@@ -265,17 +384,10 @@ class Piper(TTSBackend):
             try:
                 self._load_voice_metadata()
                 s = EngineSpecificSettings.create_from_config(self.engine_name)
-                length_scale = max(0.1, 1 + -1 * s.rate)  # maps -1 to 1 to 2 to 0.1
                 voice = self._voice_name_map.get(s.voice_name) or self._default_voice
                 model_path, config_path = self._ensure_voice_is_downloaded(voice)
             except AttributeError as e:
                 raise Exception(str(e)) from e
-            if not model_path:
-                raise Exception('Could not download voice data')
-            if 'metadata' not in voice.engine_data:
-                with open(config_path) as f:
-                    voice.engine_data['metadata'] = json.load(f)
-            audio_rate = voice.engine_data['metadata']['audio']['sample_rate']
             self._current_voice = voice
             self._utterances_being_spoken.clear()
             self._utterances_being_synthesized.clear()
@@ -284,11 +396,7 @@ class Piper(TTSBackend):
             self._pending_stderr_data = b''
             self._set_state(QTextToSpeech.State.Ready)
 
-            cmdline = list(piper_cmdline()) + [
-                '--model', model_path, '--config', config_path, '--output-raw', '--json-input',
-                '--sentence-silence', str(s.sentence_delay), '--length_scale', str(length_scale)]
-            if is_debugging():
-                cmdline.append('--debug')
+            audio_rate, cmdline = piper_process_metadata(model_path, config_path, s, voice)
             self._process.setProgram(cmdline[0])
             self._process.setArguments(cmdline[1:])
             debug('Running piper:', cmdline)
@@ -296,10 +404,7 @@ class Piper(TTSBackend):
             self._process.readyReadStandardOutput.connect(self.piper_stdout_available)
             self._process.bytesWritten.connect(self.bytes_written)
             self._process.stateChanged.connect(self._update_status)
-            fmt = QAudioFormat()
-            fmt.setSampleFormat(QAudioFormat.SampleFormat.Int16)
-            fmt.setSampleRate(audio_rate)
-            fmt.setChannelConfig(QAudioFormat.ChannelConfig.ChannelConfigMono)
+            fmt = audio_format(audio_rate)
             dev = None
             if s.audio_device_id:
                 for q in QMediaDevices.audioOutputs():
@@ -332,20 +437,14 @@ class Piper(TTSBackend):
 
     def piper_stderr_available(self) -> None:
         if self._process is not None:
+            def callback(ok, payload):
+                if ok:
+                    if self._utterances_being_synthesized:
+                        self._synthesis_done.emit()
+                else:
+                    self._errors_from_piper.append(payload.decode('utf-8', 'replace'))
             data = self._pending_stderr_data + bytes(self._process.readAllStandardError())
-            lines = data.split(b'\n')
-            for line in lines[:-1]:
-                if m := self._stderr_pat.search(line):
-                    which, payload = m.group(1), m.group(2)
-                    if which == b'info':
-                        debug(f'[piper-info] {payload.decode("utf-8", "replace")}')
-                        if payload.startswith(b'Real-time factor:') and self._utterances_being_synthesized:
-                            self._synthesis_done.emit()
-                    elif which == b'error':
-                        self._errors_from_piper.append(payload.decode('utf-8', 'replace'))
-                    elif which == b'debug':
-                        debug(f'[piper-debug] {payload.decode("utf-8", "replace")}')
-            self._pending_stderr_data = lines[-1]
+            self._pending_stderr_data = detect_end_of_data(data, callback)
 
     def _utterance_synthesized(self):
         self.piper_stdout_available()  # just in case
@@ -402,42 +501,7 @@ class Piper(TTSBackend):
     def _load_voice_metadata(self) -> None:
         if self._voices is not None:
             return
-        d = json.loads(P('piper-voices.json', data=True))
-        ans = []
-        lang_voices_map = {}
-        self._voice_name_map = {}
-        downloaded = set()
-        with suppress(OSError):
-            downloaded = set(os.listdir(self.cache_dir))
-        for bcp_code, voice_map in d['lang_map'].items():
-            lang, sep, country = bcp_code.partition('_')
-            lang = canonicalize_lang(lang) or lang
-            voices_for_lang = lang_voices_map.setdefault(lang, [])
-            for voice_name, qual_map in voice_map.items():
-                best_qual = voice = None
-                for qual, e in qual_map.items():
-                    q = Quality.from_piper_quality(qual)
-                    if best_qual is None or q.value < best_qual.value:
-                        best_qual = q
-                        mf = f'{bcp_code}-{voice_name}-{qual}.onnx'
-                        voice = Voice(bcp_code + ':' + voice_name, lang, country, human_name=voice_name, quality=q, engine_data={
-                            'model_url': e['model'], 'config_url': e['config'],
-                            'model_filename': mf, 'is_downloaded': mf in downloaded,
-                        })
-                if voice:
-                    ans.append(voice)
-                    self._voice_name_map[voice.name] = voice
-                    voices_for_lang.append(voice)
-        self._voices = tuple(ans)
-        self._voice_for_lang = {}
-        for lang, voices in lang_voices_map.items():
-            voices.sort(key=lambda v: v.quality.value)
-            self._voice_for_lang[lang] = voices[0]
-            if lang == 'eng':
-                for v in voices:
-                    if v.human_name == 'libritts':
-                        self._voice_for_lang[lang] = v
-                        break
+        self._voice_name_map, self._voices, self._voice_for_lang = load_voice_metadata()
 
     @property
     def _default_voice(self) -> Voice:
@@ -448,18 +512,12 @@ class Piper(TTSBackend):
 
     @property
     def cache_dir(self) -> str:
-        return os.path.join(cache_dir(), 'piper-voices')
-
-    def _paths_for_voice(self, voice: Voice) -> tuple[str, str]:
-        fname = voice.engine_data['model_filename']
-        model_path = os.path.join(self.cache_dir, fname)
-        config_path = os.path.join(os.path.dirname(model_path), fname + '.json')
-        return model_path, config_path
+        return piper_cache_dir()
 
     def is_voice_downloaded(self, v: Voice) -> bool:
         if not v or not v.name:
             v = self._default_voice
-        for path in self._paths_for_voice(v):
+        for path in paths_for_voice(v):
             if not os.path.exists(path):
                 return False
         return True
@@ -467,25 +525,13 @@ class Piper(TTSBackend):
     def delete_voice(self, v: Voice) -> None:
         if not v.name:
             v = self._default_voice
-        for path in self._paths_for_voice(v):
+        for path in paths_for_voice(v):
             with suppress(FileNotFoundError):
                 os.remove(path)
         v.engine_data['is_downloaded'] = False
 
     def _download_voice(self, voice: Voice, download_even_if_exists: bool = False) -> tuple[str, str]:
-        model_path, config_path = self._paths_for_voice(voice)
-        if os.path.exists(model_path) and os.path.exists(config_path):
-            if not download_even_if_exists:
-                return model_path, config_path
-        os.makedirs(os.path.dirname(model_path), exist_ok=True)
-        from calibre.gui2.tts.download import download_resources
-        ok = download_resources(_('Downloading voice for Read aloud'), _('Downloading neural network for the {} voice').format(voice.human_name), {
-                voice.engine_data['model_url']: (model_path, _('Neural network data')),
-                voice.engine_data['config_url']: (config_path, _('Neural network metadata')),
-            }, parent=widget_parent(self), headless=getattr(QApplication.instance(), 'headless', False)
-        )
-        voice.engine_data['is_downloaded'] = bool(ok)
-        return (model_path, config_path) if ok else ('', '')
+        return download_voice(voice, download_even_if_exists, parent=self, headless=False)
 
     def download_voice(self, v: Voice) -> None:
         if not v.name:
@@ -511,6 +557,122 @@ class Piper(TTSBackend):
         return True
 
 
+class PiperEmbedded:
+
+    def __init__(self):
+        self._embedded_settings = EngineSpecificSettings.create_from_config(self.engine_name, TTS_EMBEDED_CONFIG)
+        self._voice_name_map, self._voices, self._voice_for_lang = load_voice_metadata()
+        lang = get_lang()
+        lang = canonicalize_lang(lang) or lang
+        self._default_voice = self._voice_for_lang.get(lang) or self._voice_for_lang['eng']
+        self._current_voice = self._process = self._process_shutdown_event = None
+        self._current_audio_format = QAudioFormat()
+
+    def resolve_voice(self, lang: str, voice_name: str) -> Voice:
+        from calibre.utils.localization import canonicalize_lang, get_lang
+        lang = canonicalize_lang(lang or get_lang() or 'en')
+        if voice_name and voice_name in self._voice_name_map:
+            voice = self._voice_name_map[voice_name]
+        elif (voice_name := self._embedded_settings.preferred_voices.get(lang, '')) and voice_name in self._voice_name_map:
+            voice = self._voice_name_map[voice_name]
+        else:
+            voice = self._voice_for_lang.get(lang) or self._default_voice
+        return voice
+
+    def text_to_raw_audio_data(
+        self, texts: Iterable[str], lang: str = '', voice_name: str = '', format: QAudioFormat | None = None, timeout: float = 10.,
+    ) -> Iterator[bytes]:
+        if format is None:
+            format = audio_format()
+        voice = self.resolve_voice(lang, voice_name)
+        if voice is not self._current_voice:
+            self._current_voice = voice
+            self.shutdown()
+        self.ensure_process_started()
+        piper_done, errors_from_piper = [], []
+        last_output_at = monotonic()
+
+        def callback(ok, payload):
+            nonlocal last_output_at
+            if ok:
+                piper_done.append(True)
+                last_output_at = monotonic()
+            else:
+                errors_from_piper.append(payload.decode('utf-8', 'replace'))
+
+        for text in texts:
+            if not text:
+                yield b''
+            self._process.stdin.write(text.encode('utf-8', 'replace'))
+            stderr_data = b''
+            buf, piper_done, errors_from_piper = [], [], []
+            last_output_at = monotonic()
+            while not piper_done:
+                try:
+                    is_stdout, exception, data = self._from_process_queue.get(True, 1.0)
+                except Empty:
+                    if self._process.poll() is not None:
+                        raise Exception(f'piper process died with error code: {self._process.poll()} and stderr: {"".join(errors_from_piper)}')
+                    if monotonic() - last_output_at > timeout:
+                        raise TimeoutError(f'piper process produced no output for {timeout} seconds. stderr: {"".join(errors_from_piper)}')
+                else:
+                    if exception is not None:
+                        raise exception
+                    if is_stdout:
+                        buf.append(data)
+                    else:
+                        stderr_data = detect_end_of_data(stderr_data + data, callback)
+        needs_conversion = format != self._current_audio_format
+        needs_conversion
+
+    def ensure_voices_downloaded(self, specs: Iterable[tuple[str, str]], parent: QObject = None) -> None:
+        for lang, voice_name in specs:
+            voice = self.resolve_voice(lang, voice_name)
+            download_voice(voice, parent=parent, headless=parent is None)
+
+    def shutdown(self):
+        if self._process is not None:
+            self._process_shutdown_event.set()
+            self._to_process_queue.put(None)
+            self._process_shutdown_event = None
+            self._process.stdin.close()
+            self._process.kill()
+            self._process.wait()
+            self._process.stdout.close()
+            self._process.stderr.close()
+            self._process = None
+            self._stdout_reader.join()
+            self._stderr_reader.join()
+    __del__ = shutdown
+
+    def ensure_process_started(self):
+        if self._process is not None:
+            return
+        model_path, config_path = download_voice(self._current_voice, headless=True)
+        audio_rate, cmdline = piper_process_metadata(model_path, config_path, self._embedded_settings, self._current_voice)
+        self._current_audio_format = audio_format(audio_rate)
+        import subprocess
+        from threading import Thread
+        self._process_shutdown_event = Event()
+        self._stdout_reader = Thread(target=self.reader, args=(self._process_shutdown_event, self._process.stdout, True), daemon=True)
+        self._stderr_reader = Thread(target=self.reader, args=(self._process_shutdown_event, self._process.stderr, False), daemon=True)
+        self._from_process_queue = Queue()
+        self._process = subprocess.Popen(cmdline, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
+        self._stdout_reader.start()
+        self._stderr_reader.start()
+
+    def reader(self, shutdown_event: Event, pipe: BinaryIO, is_stdout: bool = False) -> None:
+        while not shutdown_event.is_set():
+            try:
+                data = pipe.read()
+            except Exception as e:
+                if not shutdown_event.is_set():
+                    self._from_process_queue.put((is_stdout, e, b''))
+                break
+            else:
+                self._from_process_queue.put((is_stdout, None, data))
+
+
 def develop():  # {{{
 
     from qt.core import QSocketNotifier