Why some videos won't play

[FunDMental]

I've been using flash got for about 6 months,
and something has bothered me for quite a while.

I don't understand why some videos from youtube play just fine, but others don't work,
When I try to play them in SMplayer, the player just shrinks to a black bar where the picture should be, and nothing else happens.

I'm stuck in dialup hell so the only way to enjoy youtube is to dl the videos to watch locally.

I have figured out that if I add .flv to a youtube "videoplayback" file the video should play.

some do, (usually the smaller files) others don't.
It really sucks to spend 3 hours downloading a video, only to find out it refuses to play.

Anyone have any idea why this happens?

Thanks in advance

[Giorgio Maone]

I believe this is a player issue.
Could you try VLC?

[therube]

Probably more correctly a codec issue.
If VLC doesn't do it, give MPlayer a try. Here's one version of it, Kovensky MPlayer.

[Anon]

It could also be because of two other reasons.
1) You entered the wrong extension. Some YT vids use the ".mp4" extension or
2) The download was broken or errored at some point and it incorrectly displayed it as done. This has happened with me before.

[Johnfull]

FLV Player For Free and RealPlayer both work with the .flv extension.
I found that dial-up often timed out before a video would complete.
I have bitten the bullet and begun paying for DSL service and have no
problems now.