Added initial parameters

tests/Unit/Format/Video/InitialParametersTest.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Tests\FFMpeg\Unit\Format\Video;
+
+use FFMpeg\Format\Video\X264;
+use Tests\FFMpeg\Unit\TestCase;
+
+class InitialParametersTest extends TestCase
+{
+    public function testApplyInitialParameters()
+    {
+        $format = new X264();
+        $format->setInitialParameters(array('-acodec', 'libopus'));
+        $this->assertEquals(array('-acodec', 'libopus'), $format->getInitialParameters());
+    }
+}