sample player bad buffering and eventual "crash"

Aug 24, 2009 at 3:15 PM
Edited Aug 24, 2009 at 3:59 PM

Folks,

using the sample starlight player (unmodified) to play vc-1 multicast streams via WMS, in IE using the active X plugin.   No encoder involved at this point, just a 24 hour recording pulled from the encoder earlier on a loop straight out of WMS.   Player and WMS are on the same LAN which has no issues with multicast.

 

First, playback seems to buffer frequently.  Watching the buffer level indicator, it will drop down to .5 frequently, and sometimes exhausts the buffer completely (at which point the video playback is affected).    Playback of the same stream on the same computer using WMP is smooth with no buffering issues.  

 

The next problem is that after the stream has been playing for some time (hour+ maybe?), the browser that the player is in will stop being responsive.  CPU for the process goes to 99%, trying to interact with the browser window takes multiple minutes for anything to respond.     When I am able to get it to respond, the player is stuck with the buffer bar up, but not doing anything.

I've been avoiding this one for a week or two, so my details may be a bit fuzzy.  I'm working on reproducing it again today and will update with anything else I can discover.

 

Looks like there's a video/audio sync issue as well.  The same multicast stream in WMP doesn't have the problem, but there's a ~~half second delay in the audio in the SL player.

 

When playback isn't buffering or being broken, things are smooth. :)   Playback of unicast (http and mms) is fine.

Any thoughts?   Is this just a problem with the sample build, perhaps?

Coordinator
Aug 24, 2009 at 4:55 PM

The buffering in a loop is a known issue, unfortunately there's no simple solution.  The problem is that when we are feeding media samples to the MediaElement playback will hang under some conditions if the audio stream loops significantly before the video stream.  As a workaround for this, we aggressively flush the buffer when we detect that any stream in the feed has looped.  This can lead to excessive buffering when playing streams in a loop, but should only happen at the loop points (or close to them).  Are you seeing buffering problems at other points in the video?

As far as the audio sync and CPU usage issues:  we will be releasing a new build in the near future that may address both of these issues.  

Aug 24, 2009 at 6:48 PM

This can lead to excessive buffering when playing streams in a loop, but should only happen at the loop points (or close to them).  Are you seeing buffering problems at other points in the video?

 

Gotcha.  Unfortunately, these don't seem to be happening on the loop (my source file is 96 hours long).   I'll note that the "position" indicator does seem to roll over a lot (somewhere north of 400k when it resets), but that doesn't always occur at the same time the buffering issue occurs.

As far as the audio sync and CPU usage issues:  we will be releasing a new build in the near future that may address both of these issues. 

Thanks.  I just recreated the hang after about 2 hours or so this time.  IE is entirely "Not Responding" and holding 50% CPU steady.  I'll have to kill the iexplore process to recover.

Does this match up to what you've been seeing?


Coordinator
Aug 29, 2009 at 5:40 AM

I just uploaded a new beta release.  No real new features, but lots of work under the hood.  Give it a whirl and see if it helps with the buffering and CPU usage issues.

Aug 31, 2009 at 2:16 PM

thanks.  any chance you could update the StarlightPlayer.zip with the new build, or tell me which files to replace from the source tree (projectstartlight-26871.zip) ?   Rebuilding anything with VS is a bit outside my scope (and available software...;)

 

tthanks.

Coordinator
Sep 1, 2009 at 6:59 PM

It should be there in the 2.0b1 release page.