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I have downloaded a few videos from the web, and overall they have a pretty good quality. But there are a lot of broken pieces in the video's and I am wondering if I can restore them back to the original.

Here is an example of what I am talking about:

alt text

I am pretty sure the quality loss is because of the compression the person used, something went wrong.

Can I bring these clips back to a better state, because some parts are blurry/pixelated for minutes.

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2  
This looks like either porn or reality tv. Neither is worth restoring. –  Josh K Jun 22 '10 at 3:37
1  
Dear Josh, don't be afraid to add information as well as opinion. –  Xavierjazz Jun 22 '10 at 5:07
    
This is Dutch reality tv, your right. And the restoration is not only to view the clip, but also on expanding my general knowledge on video editing. –  Saif Bechan Jun 22 '10 at 14:03

2 Answers 2

up vote 4 down vote accepted

This seems to be data corruption along the video stream - sometimes it could be due to the player or hard disk trashing. Have you tried switching to another player or computer to playback?

If the video file truly has corrupted data in the video stream, it is quite hard to do an auto-recovery. What you can do is to open the video file up in a video editor, and copy-replace the bad frames with the nearest good ones.

It won't be smooth, it is not a complete restore, but it sure is better than seeing pixellated junk. Alternatively, replace those corrupted frames with a picture of something really cute, like a lolcat, and in big Comic Sans type "I CAN HAZ KORRUPTED FLAMES?".

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Thank you for the suggestion. I have tried the clips is windows media player, and GOM player. Same mess in both of them, at the same times. Could this be a codec problem? –  Saif Bechan Jun 22 '10 at 2:54
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@Saif It looks like the video has corrupted keyframes - This isn't a problem with the codec per se (unless you want to argue it as a design flaw), but rather the encoder writing bad keyframes or the video file becoming corrupt. –  Darth Android Jun 22 '10 at 3:01
1  
Try VLC as Darth Android suggested, as it has self-contained codecs that works quite well. However don't keep your hopes up, usually the data stream is corrupted. –  caliban Jun 22 '10 at 3:02

Probably not. It looks like the stream or video has a few corrupted key frames. Try using an application called VLC to play the video. It will do it's best to produce the best possible video, but with missing keyframes there's not much you can do.

Most video codecs make use of a key frame (full video frame), and then make "changes" to it (lighten this block by x amount, move this block y pixels to the left, change this block to z imagedata) until the next keyframe arrives, usually every couple of seconds. If the scene stays relatively the same, it could be quite some time before the next keyframe is encoded however. When a keyframe becomes corrupt, the video player has no choice but to apply the edits to the last known image - often quite different from what the keyframe was, since keyframes occur often in association with a scene change or otherwise when more than x% of the screen needs to be redrawn. When the edits begin to be made to the wrong original image, you wind up with the artifacts as shown on the right-hand images. These edits also build upon themselves, which only compounds the problem until the next keyframe is available.

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Still no luck with VLC player. How did these keyframes become corrupted. Did it happen during the compression, or is there another explanation. –  Saif Bechan Jun 22 '10 at 3:23
    
If you freshly encoded the video yourself and saved it to a file, I would have to blame the encoder. Otherwise, any time the file was transferred, there was an opportunity for it to corrupt. This isn't an uncommon situation if you streamed the video in real time, as frames get dropped if available bandwidth dips. If it was downloaded or otherwise only copied around, I would suspect the encoder. Are you sure the person you got it from didn't stream it from a 3rd party? –  Darth Android Jun 22 '10 at 5:19
    
I have no idea what the original owner did with it, I should ask him. Thanks for all help, I definitely learned something. –  Saif Bechan Jun 22 '10 at 14:05

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