Replace torchaudio.save with soundfile.write; add EPUB loader node

- nodes/generator.py: swap torchaudio.save for soundfile.write to avoid
  torchcodec/FFmpeg dependency crash in environments without FFmpeg shared libs
- nodes/epub_loader.py: new OmniVoiceEpubLoader node for loading EPUB chapters
- tests/test_epub_loader.py: 8 tests for the EPUB loader
- install.py: add beautifulsoup4 to runtime deps
- __init__.py, nodes/__init__.py: register OmniVoiceEpubLoader

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nodes/__init__.py

@@ -1,4 +1,5 @@
 from .loader import OmniVoiceModelLoader
 from .generator import OmniVoiceGenerate
+from .epub_loader import OmniVoiceEpubLoader
 
-__all__ = ["OmniVoiceModelLoader", "OmniVoiceGenerate"]
+__all__ = ["OmniVoiceModelLoader", "OmniVoiceGenerate", "OmniVoiceEpubLoader"]

nodes/epub_loader.py

@@ -0,0 +1,109 @@
+import zipfile
+import io
+import xml.etree.ElementTree as ET
+from bs4 import BeautifulSoup
+
+
+def _local(tag):
+    """Strip XML namespace prefix, return local tag name."""
+    return tag.split('}')[-1]
+
+
+def _extract_chapters(epub_path):
+    """Parse EPUB and return list of {"title": str|None, "text": str}."""
+    chapters = []
+    with zipfile.ZipFile(epub_path, 'r') as zf:
+        # 1. Find OPF path from container.xml
+        container = ET.fromstring(zf.read('META-INF/container.xml'))
+        rootfile = next(
+            el for el in container.iter()
+            if _local(el.tag) == 'rootfile'
+        )
+        opf_path = rootfile.attrib['full-path']
+        opf_dir = opf_path.rsplit('/', 1)[0] + '/' if '/' in opf_path else ''
+
+        # 2. Parse OPF: build manifest and spine
+        opf = ET.fromstring(zf.read(opf_path))
+        manifest = {
+            el.attrib['id']: el.attrib['href']
+            for el in opf.iter()
+            if _local(el.tag) == 'item'
+            and 'xhtml' in el.attrib.get('media-type', '')
+        }
+        spine = [
+            el.attrib['idref']
+            for el in opf.iter()
+            if _local(el.tag) == 'itemref'
+        ]
+
+        # 3. Extract text from each chapter XHTML
+        for idref in spine:
+            href = manifest.get(idref)
+            if href is None:
+                continue
+            xhtml = zf.read(opf_dir + href).decode('utf-8', errors='replace')
+            soup = BeautifulSoup(xhtml, 'html.parser')
+            for tag in soup(['script', 'style']):
+                tag.decompose()
+            # Title: <title> → <h1/h2/h3> → None
+            title = None
+            if soup.title and soup.title.string:
+                title = soup.title.string.strip()
+            if not title:
+                for hn in ['h1', 'h2', 'h3']:
+                    tag = soup.find(hn)
+                    if tag:
+                        title = tag.get_text(strip=True)
+                        break
+            text = soup.get_text(separator=' ', strip=True)
+            chapters.append({"title": title, "text": text})
+
+    return chapters
+
+
+class OmniVoiceEpubLoader:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "epub_path": ("STRING", {
+                    "default": "",
+                    "tooltip": "Absolute path to the .epub file to load.",
+                }),
+                "chapter_start": ("INT", {
+                    "default": 1, "min": 1, "max": 9999, "step": 1,
+                    "tooltip": "First chapter to include (1-indexed). Clamped to valid range automatically.",
+                }),
+                "chapter_end": ("INT", {
+                    "default": 1, "min": 1, "max": 9999, "step": 1,
+                    "tooltip": "Last chapter to include (1-indexed, inclusive). Clamped automatically. If less than chapter_start, set to chapter_start.",
+                }),
+            },
+        }
+
+    RETURN_TYPES = ("STRING", "STRING")
+    RETURN_NAMES = ("text", "chapter_list")
+    FUNCTION = "load_epub"
+    CATEGORY = "OmniVoice"
+
+    def load_epub(self, epub_path, chapter_start, chapter_end):
+        chapters = _extract_chapters(epub_path)
+        n = len(chapters)
+
+        if n == 0:
+            return ("", "")
+
+        start = max(1, min(chapter_start, n))
+        end   = max(start, min(chapter_end, n))
+
+        # chapter_list: all chapters regardless of selection
+        chapter_list = "\n".join(
+            f"{i}. {ch['title'] if ch['title'] else f'Chapter {i}'}"
+            for i, ch in enumerate(chapters, 1)
+        )
+
+        # text: selected range joined by delimiter
+        selected = chapters[start - 1 : end]
+        text = "\n\n---\n\n".join(ch["text"] for ch in selected)
+
+        return (text, chapter_list)

nodes/generator.py

@@ -1,7 +1,7 @@
 import tempfile
 import os
 import torch
-import torchaudio
+import soundfile as sf
 
 
 class OmniVoiceGenerate:
@@ -109,7 +109,9 @@ class OmniVoiceGenerate:
             tmp.close()
             try:
                 ref_waveform = ref_audio["waveform"].squeeze(0).cpu()  # (channels, samples)
-                torchaudio.save(tmp_path, ref_waveform, int(ref_audio["sample_rate"]))
+                audio_np = ref_waveform.numpy()
+                # soundfile expects (samples,) for mono or (samples, channels) for multi-channel
+                sf.write(tmp_path, audio_np[0] if audio_np.shape[0] == 1 else audio_np.T, int(ref_audio["sample_rate"]))
                 kwargs["ref_audio"] = tmp_path
                 if ref_text:
                     kwargs["ref_text"] = ref_text