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Question regarding blockiness at outer fringe of video frame

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Mike Konstan
Question regarding blockiness at outer fringe of video frame
on Aug 27, 2008 at 10:53:19 pm

Here's another question that came up, different project...

I am seeing what appears to be flickering square blocks which are appearing randomly in a single column or row at the outer edge of a Windows Media file as it is played in PowerPoint. The video file plays fine by itself when viewed in Windows Media Player. It's just when it runs within a PowerPoint presentation that we see this problem. 2 files have the issue-- one gets the problem on the outer right edge, and the other shows it at the bottom of the screen. Both files are approximately 856x480. PowerPoint is 2003 version.

By the way, the presentation works fine on other computers running PowerPoint2003. Info about the files shows the data rate running about 988 kbps... seems a bit too high... We're wondering if it's just too high a bitrate for the particular computer having the problem, or perhaps a graphics card issue...?

Thanks!

-Mike





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Daniel Low
Re: Question regarding blockiness at outer fringe of video frame
on Aug 28, 2008 at 1:38:12 pm

It could be anything. I don't think the data rate is too high though, unless the PC is ancient. I'd try reducing the video frame size to something like 640x360 or less.

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Mike Konstan
Re: Question regarding blockiness at outer fringe of video frame
on Aug 29, 2008 at 1:29:57 pm

They tried re-encoding the file using ProCoder on the PC, and got rid of the problem. Of course, they just cranked up the bit rate super high and that's apparently what did the trick.

My file was encoded at around 1000 kbps because they originally wanted to keep the quality up but the file size small since there were many videos to include in the presentation. The settings I used seemed to be the best compromise, it's just that we started getting the blockiness on the edge on that particular PC. That file was also difficult to do since it involved slowly sweeping lighting effects that revealed product features in black limbo.

I checked their re-encoded file and the bit rate was all the way up to 16,000kbps! The guys just used the "High Quality VBR" setting in ProCoder and cranked up the Quality setting to 100% as well. So the resulting file looked great, the bit rate is super high and the file size nearly doubled to about 52 mb.

I think they could have increased the quality without taking the bit rate up quite so high-- seems like overkill on the data rate. But it works for them...

Thanks again for your help with decyphering these issues, Daniel!

-Mike


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Daniel Low
Re: Question regarding blockiness at outer fringe of video frame
on Aug 29, 2008 at 2:30:38 pm

Yup, 16Mb/s is crazy. You can do 1920x1080 (H.264 or WMV) at around 10-12Mb/s and it'll look fantastic (given the right source, of course).

I hope you don't run in to more problems as a result!

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Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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