diff --git a/backend/test/tests.js b/backend/test/tests.js
index ec18dd5..0a05f6b 100644
--- a/backend/test/tests.js
+++ b/backend/test/tests.js
@@ -388,10 +388,18 @@ describe('Downloader', function() {
     });
 
     it('Inject args', async function() {
-        const original_args = ['--no-resize-buffer', '-o', '%(title)s', '--no-mtime'];
-        const new_args = ['--age-limit', '25', '--yes-playlist', '--abort-on-error', '-o', '%(id)s'];
-        const updated_args = utils.injectArgs(original_args, new_args);
-        assert(updated_args, ['--no-resize-buffer', '--no-mtime', '--age-limit', '25', '--yes-playlist', '--abort-on-error', '-o', '%(id)s']);
+        const original_args1 = ['--no-resize-buffer', '-o', '%(title)s', '--no-mtime'];
+        const new_args1 = ['--age-limit', '25', '--yes-playlist', '--abort-on-error', '-o', '%(id)s'];
+        const updated_args1 = utils.injectArgs(original_args1, new_args1);
+        const expected_args1 = ['--no-resize-buffer', '--no-mtime', '--age-limit', '25', '--yes-playlist', '--abort-on-error', '-o', '%(id)s'];
+        assert(JSON.stringify(updated_args1), JSON.stringify(expected_args1));
+
+        const original_args2 = ['-o', '%(title)s.%(ext)s', '--write-info-json', '--print-json', '--audio-quality', '0', '-x', '--audio-format', 'mp3'];
+        const new_args2 =  ['--add-metadata', '--embed-thumbnail', '--convert-thumbnails', 'jpg'];
+        const updated_args2 = utils.injectArgs(original_args2, new_args2);
+        const expected_args2 =  ['-o', '%(title)s.%(ext)s', '--write-info-json', '--print-json', '--audio-quality', '0', '-x', '--audio-format', 'mp3', '--add-metadata', '--embed-thumbnail', '--convert_thumbnails', 'jpg'];
+        console.log(updated_args2);
+        assert(JSON.stringify(updated_args2), JSON.stringify(expected_args2));
     });
 });
 
diff --git a/backend/utils.js b/backend/utils.js
index b456659..e12fc03 100644
--- a/backend/utils.js
+++ b/backend/utils.js
@@ -421,10 +421,11 @@ async function fetchFile(url, path, file_label) {
 //  - if it doesn't exist and has value, add both arg and value
 //  - if it doesn't exist and doesn't have value, add arg
 function injectArgs(original_args, new_args) {
+    const updated_args = original_args.slice();
     try {
         for (let i = 0; i < new_args.length; i++) {
             const new_arg = new_args[i];
-            if (!new_arg.startsWith('-') && !new_arg.startsWith('--')) continue;
+            if (!new_arg.startsWith('-') && !new_arg.startsWith('--') && i > 0 && original_args.includes(new_args[i - 1])) continue;
             
             if (CONSTS.YTDL_ARGS_WITH_VALUES.has(new_arg)) {
                 if (original_args.includes(new_arg)) {
@@ -432,10 +433,10 @@ function injectArgs(original_args, new_args) {
                     original_args.splice(original_index, 2);
                 }
 
-                original_args.push(new_arg, new_args[i + 1]);
+                updated_args.push(new_arg, new_args[i + 1]);
             } else {
                 if (!original_args.includes(new_arg)) {
-                    original_args.push(new_arg);
+                    updated_args.push(new_arg);
                 }
             }
         }
@@ -444,7 +445,7 @@ function injectArgs(original_args, new_args) {
         logger.warn(`Failed to inject args (${new_args}) into (${original_args})`);
     }
 
-    return original_args;
+    return updated_args;
 }
 
 // objects