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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:
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.
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?".
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.
