I just discovered what was causing the issue in the video playback: it was my driver.
I'd notice, at the moment that I played a video, showing the issue and I recorded it a few hours ago. And the video that I recorded using a software (like some videos played on opera browser) was having the same problem with stretched images. Since I noticed that, I downloaded another drive version for my video card and now the problem is finally over.

I just discovered what was causing the issue in the video playback: it was my driver.
I'd notice, at the moment that I played a video, showing the issue and I recorded it a few hours ago. And the video that I recorded using a software (like some videos played on opera browser) was having the same problem with stretched images. Since I noticed that, I downloaded another drive version for my video card and now the problem is finally over.

Can't you help me, right?

I just confirm that videos on dailymotion are with the same issue.

@leocg Yes, it is. Zooming in and out, the issue continues.

@leocg I am sorry. We are talking about Opera for Windows.

@leocg I did all the steps correctly, but the issue in the videos continues... I can garantee that this issue is only happening in Opera. I am using the last version of Opera Mini and I have installed in my hd the windows 7 ultimate x64 sp 1.

The problem is about video playback (especifically from the sites I mention in the title) and consists in stretched images, as they were zoomed by some kind of option. This problem persists in Vimeo videos always when I click to play some video, however in Facebook this problem happens sometimes in random moments as in youtube videos.
A long time has passed by, since this problem has apeared, I already uninstalled the browser, cleaned all the registry keys with the "Ccleaner" software and deleted folders and archives related with Opera Mini, but without sucess.
[On firefox brower]

[The same video at the time open on Opera Mini browser]