add text chunking for long-form generation (Fixes #4)

web/README.md

@@ -2,6 +2,10 @@
 
 This example demonstrates how to use Supertonic in a web browser using ONNX Runtime Web.
 
+## 📰 Update News
+
+**2025.11.19** - Added automatic text chunking for long-form inference. Long texts are split into chunks and synthesized with natural pauses.
+
 ## Features
 
 - 🌐 Runs entirely in the browser (no server required for inference)

web/helper.js

@@ -72,7 +72,7 @@ export class TextToSpeech {
         this.sampleRate = cfgs.ae.sample_rate;
     }
 
-    async call(textList, style, totalStep, progressCallback = null) {
+    async _infer(textList, style, totalStep, progressCallback = null) {
         const bsz = textList.length;
         
         // Process text
@@ -176,6 +176,35 @@ export class TextToSpeech {
         return { wav, duration };
     }
 
+    async call(text, style, totalStep, silenceDuration = 0.3, progressCallback = null) {
+        if (style.ttl.dims[0] !== 1) {
+            throw new Error('Single speaker text to speech only supports single style');
+        }
+        const textList = chunkText(text);
+        let wavCat = [];
+        let durCat = 0;
+        
+        for (const chunk of textList) {
+            const { wav, duration } = await this._infer([chunk], style, totalStep, progressCallback);
+            
+            if (wavCat.length === 0) {
+                wavCat = wav;
+                durCat = duration[0];
+            } else {
+                const silenceLen = Math.floor(silenceDuration * this.sampleRate);
+                const silence = new Array(silenceLen).fill(0);
+                wavCat = [...wavCat, ...silence, ...wav];
+                durCat += duration[0] + silenceDuration;
+            }
+        }
+        
+        return { wav: wavCat, duration: [durCat] };
+    }
+
+    async batch(textList, style, totalStep, progressCallback = null) {
+        return await this._infer(textList, style, totalStep, progressCallback);
+    }
+
     sampleNoisyLatent(duration, sampleRate, baseChunkSize, chunkCompress, latentDim) {
         const bsz = duration.length;
         const maxDur = Math.max(...duration);
@@ -347,6 +376,48 @@ export async function loadTextToSpeech(onnxDir, sessionOptions = {}, progressCal
     return { textToSpeech, cfgs };
 }
 
+/**
+ * Chunk text into manageable segments
+ */
+function chunkText(text, maxLen = 300) {
+    if (typeof text !== 'string') {
+        throw new Error(`chunkText expects a string, got ${typeof text}`);
+    }
+    
+    // Split by paragraph (two or more newlines)
+    const paragraphs = text.trim().split(/\n\s*\n+/).filter(p => p.trim());
+    
+    const chunks = [];
+    
+    for (let paragraph of paragraphs) {
+        paragraph = paragraph.trim();
+        if (!paragraph) continue;
+        
+        // Split by sentence boundaries (period, question mark, exclamation mark followed by space)
+        // But exclude common abbreviations like Mr., Mrs., Dr., etc. and single capital letters like F.
+        const sentences = paragraph.split(/(?<!Mr\.|Mrs\.|Ms\.|Dr\.|Prof\.|Sr\.|Jr\.|Ph\.D\.|etc\.|e\.g\.|i\.e\.|vs\.|Inc\.|Ltd\.|Co\.|Corp\.|St\.|Ave\.|Blvd\.)(?<!\b[A-Z]\.)(?<=[.!?])\s+/);
+        
+        let currentChunk = "";
+        
+        for (let sentence of sentences) {
+            if (currentChunk.length + sentence.length + 1 <= maxLen) {
+                currentChunk += (currentChunk ? " " : "") + sentence;
+            } else {
+                if (currentChunk) {
+                    chunks.push(currentChunk.trim());
+                }
+                currentChunk = sentence;
+            }
+        }
+        
+        if (currentChunk) {
+            chunks.push(currentChunk.trim());
+        }
+    }
+    
+    return chunks;
+}
+
 /**
  * Write WAV file to ArrayBuffer
  */

web/main.js

@@ -186,15 +186,15 @@ async function generateSpeech() {
         `;
         
         const totalStep = parseInt(totalStepInput.value);
-        const textList = [text];
         
         showStatus('ℹ️ <strong>Generating speech from text...</strong>');
         const tic = Date.now();
         
         const { wav, duration } = await textToSpeech.call(
-            textList, 
+            text, 
             currentStyle, 
-            totalStep, 
+            totalStep,
+            0.3,
             (step, total) => {
                 showStatus(`ℹ️ <strong>Denoising (${step}/${total})...</strong>`);
             }