fix: Change ffmpeg to post process at priority 20 (#21587)

Co-authored-by: Matt Henkes <mjhenkes@gmail.com>

Author: rrauenza

packages/server/lib/video_capture.ts

@@ -284,7 +284,9 @@ export async function process (name, cname, videoCompression, ffmpegchaptersConf
     debug('processing video from %s to %s video compression %o',
       name, cname, videoCompression)
 
-    const command = ffmpeg()
+    const command = ffmpeg({
+      priority: 20,
+    })
     .addOptions([
       // These flags all serve to reduce initial buffering, especially important
       // when dealing with very short videos (such as during component tests).