To synchronize/sync wmv, please install the latest Windows Media Player which contains the latest wmv codec first.  

Download Audio Video Synchronizer which can synchronize audio/video of a wmv file. Click the Options button, select  Output Format as WMV in the following dialog box.

1. The default Resolution is original size of the clip. If you want to change the resolution of the clip, you can choose other resolutions or Custom size.

2. Resize mode:

    Preserve aspect ratio: The video is resized to fit the target frame along one dimension, while preserving the aspect ratio. If the ratio of width to height in the image does not match the ratio in the target frame, it creates a letterbox.

    Stretch: The video is stretched to fit the target frame size in both dimensions, without preserving the aspect ratio.

    If you want to adjust the aspect ratio of the output clip, please choose the Stretch mode and change a new resolution.

3. If you want to change the size of output file, Please change the Video encoding bitrate or Audio encoding bitrate.  The Encoding bitrate is bigger, the picture or sound is clearer, but the output file is bigger.

RealMedia is created by RealNetworks Inc. RV stands for Real Video.

To synchronize/sync rv or realmedia, please install the latest RealPlayer if your Windows has not installed it. Download RealMedia Splitter, use the command line "regsvr32 RealMediaSplitter.ax" to register it.

There is not rv muxer based on DirectShow at present. It is better to select wmv as output format.