Strange blurry square small spots in Video Studio Editor 11

project mayhem · Post by **project mayhem** » Wed Dec 19, 2007 8:18 pm

I keep getting some strange blurry square spots in my video preview screen on some of my video files in "Video Studio Editor" and the same spots that are square shape also end up in the final rendered video file. The were not there when i first started editing my clips, the just came out of the blue.

All clips are in MPEG-1 format and i know it is not my computer or hardware issue, because ive ran the same project on 2 differnt computers and 2 differnt windows XP and Vista, and i still get the same problem.

I have been using Distort clip and some video filters in my project and think it is a bug in VS11.

DVDDoug · Post by **DVDDoug** » Thu Dec 20, 2007 1:21 am

All clips are in MPEG-1 format... I have been using Distort clip and some video filters in my project..

This may just be unavoidable artifacts caused by de-coding and re-coding the MPEG. When you apply a filter or effect to an MPEG, the data has to be de-compresed in order to process the video. After processing, the video has to be re-compressed. Since MPEG is lossy compression, the quality is degraded with the 2nd lossy-compression step .

You can't avoid the recoding loss, but you may have better luck with a special-purpose MPEG editor (assuming your stuck with MPEGs). I use Womble. Of course, every video editor has different effects & filters, and you may not be able to duplicate the effects with a different one.

Ideally, you would do all of your editing in an uncompressed (or less compressed) format, and then the file would be compressed to it's final format once, as a final step. AVI/DV (from a MiniDV camcorder) is a very popular format. At 13GB per hour, it is less compressed than most formats, and it's one of the best formats to work with.

sjj1805 · Post by **sjj1805** » Thu Dec 20, 2007 1:22 am

MPEG1 is a low quality video format that was designed for use with standard CD discs allowing you to get up to 74 minutes of VHS quality video onto a standard CD.

We now use MPEG2 and DVD Discs - in fact the next generation is now out - High Definition / Blue Ray where you still use MPEG2 but with higher bit rates and discs that hold 25 Gigabytes of data.

Those spots you mention are termed blockiness.
Take a small low quality jpg and enlarge it and you will see a similar result.

project mayhem · Post by **project mayhem** » Thu Dec 20, 2007 3:32 pm

Thanks both. I will just have to use a better video format in future.