# MPEG question

**URL:** <https://boards.straightdope.com/t/mpeg-question/181775>\
**Category:** Factual Questions\
**Created:** [June 14, 2003, 9:21am UTC](https://boards.straightdope.com/t/mpeg-question/181775 "2003-06-14T09:21:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Vlad\_M.Paler](https://avatars.discourse-cdn.com/v4/letter/v/d26b3c/32.png) [@Vlad\_M.Paler](https://boards.straightdope.com/u/Vlad_M.Paler)\
**Post date:** [June 14, 2003, 9:21am UTC](https://boards.straightdope.com/t/mpeg-question/181775/1 "2003-06-14T09:21:35Z")

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I sometimes download certain, uh…educational videos off the internet, and often I run into a problem: The length of the video is short, say 60 seconds, but the file itself is much larger than that. If I “fast forward” it with that awful control thing in WMP and QT, it’ll jump ahead several minutes, but still only play for the remaining 50 seconds or so.

Boy, this is hard to describe. Anyone know what I’m talking about and what I can do about it?

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**Author:** ![GuanoLad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guanolad/32/42_2.png) [@GuanoLad](https://boards.straightdope.com/u/GuanoLad)\
**Post date:** [June 14, 2003, 12:26pm UTC](https://boards.straightdope.com/t/mpeg-question/181775/2 "2003-06-14T12:26:05Z")

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Usually that’s because it’s a partially downloaded file.

I believe information such as file length and compression ratio etc are hardcoded at the beginning of the file, so when the player plays it, it believes those stats, even if the whole file is not present.

However, I could be wrong. This is my guess from limited experience in playing and making mpeg files.