When skipping ahead while playing WMV file, DownloadProgressOffset stays at 0 and entire file is downloaded

Sep 19, 2012 at 12:54 AM

We have observed that in some configurations, when playing WMV videos using ProgressiveDownload plugin, if video position cursor is dragged ahead of current position (or if current position is set via [player].Position = ...), the entire video is downloaded before the video playback resumes.


This happens on Windows with Chrome and Opera as well as on Mac with Safari (and Silveright 5/SMF2.7), whereas same Silverlight application works fine with MSIE or Firefox on Windows and Firefox on Mac.

This problem seems to be caused by the fact that the mediaElement ignores the new playback position while doing the progressive download of the WMV file. This is confirmed by the fact that the DownloadProgressOffset stays at 0 even after the skip ahead.

This may be related to https://smf.codeplex.com/workitem/21380 or other issues with failing <MediaElement>.Position


Any suggestion is welcome, as this is causing trouble on MacOS.

Nov 5, 2012 at 3:52 PM

I've seen this same behaviour using Chrome on XP.

When a user skips ahead it will buffer and seems to download the file up to that point before beginning to play again.

IE & Firefox on same machine work fine.

Any thoughts?