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Closed Captions Fail After First Media in Playlist


I'm experiencing an issue with Closed Captioning. I have been able to reproduce this with the most simple implementation of SMF I can think of. The issue happens when there's a playlist of more than one item, let's say two items, and they both have marker resources for Closed Captioning. When playback begins on the first item, I click the CC button and the captions display as expected. Then the player moves on to the next item and the captions won't display. If I come back to the first item and play that again, the captions don't work even though they were there at the start. I try to toggle the CC button on/off but it doesn't help.
Below is my very simple repro that I put into a basic Silverlight project template. I'm attaching my sample captions file. (The second caption file is just a copy of the first, I wanted to see if referencing a different file helped but it didn't.)
            <Media:PlaylistItem MediaSource="">
                    <Media:MarkerResource Format="TTAF1-DFXP" Source="SampleCaptionFile.xml" />
            <Media:PlaylistItem MediaSource="">
                    <Media:MarkerResource Format="TTAF1-DFXP" Source="SampleCaptionFile2.xml" />

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krohling wrote Sep 23, 2010 at 8:55 PM

Hi DarKow, thanks for reporting this issue. We have fixed it in our main branch and it will be generally available in our next release. In the meantime you can fix it in the SMF source code by adding a single line of code to the Unload() method on Microsoft.SilverlightMediaFramework.Plugins.TimedText.MarkerProvider.

public void Unload()
        IsLoaded = false;
        Source = null;
        _previousMarkers.Clear();  //<-- Add this line
        PluginUnloaded.IfNotNull(i => i(this));
        SendLogEntry(KnownLogEntryTypes.TimedTextMarkerProviderUnloaded, message: TimedTextMediaPluginResources.TimedTextMediaPluginUnloadedLogMessage);

DarKow wrote Sep 24, 2010 at 9:05 PM

Thanks. I was in a hurry and ended up tracking it down and fixing it on my own in a very similar way, though your way is even simpler. :o) In either case, glad to help!

wrote Jul 14, 2011 at 3:54 PM

wrote Feb 22, 2013 at 1:33 AM

wrote May 16, 2013 at 12:48 PM

wrote May 16, 2013 at 12:48 PM

wrote Jun 14, 2013 at 8:32 AM

shanawazpasha wrote Aug 21, 2014 at 8:02 PM


We are experiencing the same issue. We're seeing the Closed Caption for the very first stream and then later switching to other stream displays no Closed Caption.

We're referring to v2.6 libraries of SMFPlayer since ours is a Silverlight 4 streaming application.

Any help is highly appreciated.

Thanks & Regards