Merge pull request #235 from seminelee/master

Add `mainName` option，the main function name of custom ffmpeg-core.js script. And catch the exit Error.

Author: jeromewu

src/createFFmpeg.js

@@ -88,7 +88,7 @@ module.exports = (_options = {}) => {
           return prefix + path;
         },
       });
-      ffmpeg = Core.cwrap('proxy_main', 'number', ['number', 'number']);
+      ffmpeg = Core.cwrap(options.mainName || 'proxy_main', 'number', ['number', 'number']);
       log('info', 'ffmpeg-core loaded');
     } else {
       throw Error('ffmpeg.wasm was loaded, you should not load it again, use ffmpeg.isLoaded() to check next time.');
@@ -178,7 +178,11 @@ module.exports = (_options = {}) => {
       throw NO_LOAD;
     } else {
       running = false;
-      Core.exit(1);
+      try {
+        Core.exit(1);
+      } catch(e) {
+        console.log('catch core exit error', e);
+      }
       Core = null;
       ffmpeg = null;
       runResolve = null;