Revert to duration ratio for audio

Author: WillyJL

src/createFFmpeg.js

@@ -58,14 +58,23 @@ module.exports = (_options = {}) => {
           readFrames = true;
         }
       } else if (readFrames && message.startsWith('    Stream')) {
-        const fps = parseFloat(message.match(/(\d+) fps/)[1]);
-        frames = duration * fps;
+        const match = message.match(/(\d+) fps/);
+        if (match) {
+          const fps = parseFloat(match[1]);
+          frames = duration * fps;
+        } else {
+          frames = 0;
+        };
         readFrames = false;
       } else if (message.startsWith('frame') || message.startsWith('size')) {
         const ts = message.split('time=')[1].split(' ')[0];
         const t = ts2sec(ts);
         const f = parseFloat(message.match(/frame=\s*(\d+)/)[1]);
-        ratio = Math.min(f / frames, 1);
+        if (frames) {
+          ratio = Math.min(f / frames, 1);
+        } else {
+          ratio = t / duration;
+        };
         prog({ ratio, time: t });
       } else if (message.startsWith('video:')) {
         prog({ ratio: 1 });