Can I fix a VCD?

[Haopengyou]

I have a new promotional vcd that occasionally has "squares of pixelation" randomly throughout the video. Is there any way to repair this?

[tomlee59]

The answer is "maybe." If the cause is a marginal burn, and assuming it's not simply a dirty disc, then you might be able to regenerate a better disc by copying it. A copy sometimes can, surprisingly, be better than the original because during copying the system has time to attempt multiple retries at reading the data. During real-time playback, you don't have as much of an opportunity.

So, if you know that the problem is the disc, and not a dirty lens, this method may help.

Good luck!

[aedipuss]

no you can't fix it, unless you have the original material and can try to encode it to mpeg-1 again. once it's encoded into the video it's toast.

[jman98]

Aedipuss is right. You won't be able to fix this. tomlee59 is talking about something that while possible, there is only about a 1% chance this is your problem. Most likely your problem is typical of VCD - the low bit rate can lead to pixelation. Pixelation can only be stopped before the video is encoded to VCD, so you would have to re-encode from the video source and use a better encoder and better settings for the encode to avoid pixelation as much as possible. Because VCD has a very low video bit rate, it may be impossible to stop all pixelation.

[tomlee59]

One way to narrow down the possibilities in advance of an experiment is to see if the pixelation occurs in regions of high motion/high detail. If so, then the problem is not likely fixable, as the cause is then the fundamental limitations of the VCD standard itself, as suggested by the other posters.

However, if your experience is like mine, where some VCDs are burned on not great media at higher-than-prudent speeds, then you'll be noticing this pixelation (and even audio chirps and such) even when not much is going on (and it'll tend to be bursty). It's for this case where the disc copy/regeneration method has some chance of working.

Of course, since it's not a very time-intensive or expensive experiment just to try it, there's no reason not to go ahead and give it a shot and see. At worst, you'll be out the cost of a blank disc and some CPU cycles.

Btw, I recommend burning at no faster than, say, 8x. The reduced error correction capability of the VCD standard leaves it much more sensitive to imperfect burns, fingerprint smudges, etc. Burning at speeds well below the rated capabilities of the media and drive tend to reduce the reliance on error correction. And it goes without saying that you should use good media.

[lordsmurf]

If you encode the video to 352x480 for DVD, and run MSU Deblock in VirtualDub -- maybe a few other filters, too -- then it can be improved, sure. How much depends on how damaged it is.

Sometimes it's worth it, sometimes not.

[Haopengyou]

Thanks! I will give it a try.