Use libopus and speed up VP9 encoding

tubesync/sync/youtube.py

@@ -279,9 +279,11 @@ def download_media(
     codec_options = list()
     ofn = ytopts['outtmpl']
     if 'av1-' in ofn:
-        codec_options = ['-c:v', 'libsvtav1', '-preset', '8', '-crf', '35']
+        codec_options.extend(['-c:v', 'libsvtav1', '-preset', '8', '-crf', '35'])
     elif 'vp9-' in ofn:
-        codec_options = ['-c:v', 'libvpx-vp9', '-b:v', '0', '-crf', '31']
+        codec_options.extend(['-c:v', 'libvpx-vp9', '-b:v', '0', '-crf', '31', '-row-mt', '1'])
+    if '-opus' in ofn:
+        codec_options.extend(['-c:a', 'libopus'])
     set_ffmpeg_codec = not (
         ytopts['postprocessor_args'] and
         ytopts['postprocessor_args']['modifychapters+ffmpeg']