Why only audio was converted, the video seems black after converting?
Before version 5.5, the product depends on corresponding ACM compatible video codec installed on your system to decoding video. although the video may be playable on your system, you can’t got the video in converting result since the video is only playable with DirectX. You must find and install a corresponding codec first. You can find the codec name in the “Video Source” dialog. Version 5.5 depends on DirectShow Video codec to decoding video, we strongly recommendate you install ffdshow codec first.