Add music

server-plugins/flatten-paths.js

@@ -7,6 +7,10 @@ export class FlattenPathsPlugin extends Plugin {
   }
   async applyPrerender(originalManuscript, jobId) {
     let transcript = originalManuscript.transcript
+
+    if (originalManuscript.bgMusic) {
+      originalManuscript.bgMusic = path.join('public', path.basename(originalManuscript.bgMusic));
+    }
     for (let item of transcript) {
       if (item.mediaAbsPaths && item.mediaAbsPaths.length > 0) {
         item.mediaAbsPaths = item.mediaAbsPaths.map((mediaObj) => {

utils/CaptionRender.js

@@ -103,12 +103,22 @@ export class CaptionRenderer {
       filterComplex += `;[vout0]copy[finalv];[aout0]copy[finala]`;
     }
 
-    // Execute single ffmpeg command
+    // Add background music if present
+    const { bgMusic, bgMusicVolume = 0.25, bgMusicDuration = 3 * 60 } = originalManuscript;
+    let bgMusicInputIndex = null;
+    if (bgMusic) {
+      inputs.push('-i', bgMusic);
+      bgMusicInputIndex = inputIndex;
+      inputIndex++;
+      // Mix bgMusic with finala
+      filterComplex += `;[${bgMusicInputIndex}:a]volume=${bgMusicVolume}[bgmvol];[finala][bgmvol]amix=inputs=2:duration=first:dropout_transition=2[mixeda]`;
+    }
+
     await this.runFFmpeg([
       ...inputs,
       '-filter_complex', filterComplex,
       '-map', '[finalv]',
-      '-map', '[finala]',
+      '-map', bgMusic ? '[mixeda]' : '[finala]',
       '-c:v', 'libx264',
       '-c:a', 'aac',
       '-y',