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I tried DVD-ISO burn compilation to burn some files which finished with warnings on data verification

#34 SectorVerify 11 File Cdrdrv.cpp, Line 11816
Sector 1080125 on disc has different content to source

SectorVerify 11 File Cdrdrv.cpp, Line 11816
Sector 1332468 on disc has different content to source

How much information am i losing here?

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up vote 2 down vote accepted

Since it's a video, and only two sectors in total, not much. However, if it were up to me, I would re-burn the image to a different disk. Write errors do occur depending on the quality of the media (1 in 10 for cheap discs, 1 in 100 for quality ones). If that was text, encrypted data, or other data, I would not risk it.

For your information, a sector on a DVD is only 2048 bytes, or 2 kilobytes. Since the verification only tells you the sectors do not match, but doesn't tell you which bytes are different, then assume that the whole 2 kB is different (it could only be a single bit that doesn't match, but you don't know).

However, let's put that into perspective. You have two bad sectors (so 4 kB total) on a DVD with a capacity of just over 4 GB. So, let's make things simple (and assume 1 kB = 1000 bytes), and assume that your DVD has 4 GB of data, which equals 4,000 MB, which equals 4,000,000 kB. So, you lost 1/1000000 of your data.

For a 2 hour video, this would equate to 0.0072 seconds, or 7.2 ms of lost information (assuming a constant bit rate). If your movie is at 30 frames per second, then in total you only lost 0.216 of a single frame in total. So for both of those bad sectors, you lost 1/10 of the video information for a single frame - and that's a worst-case scenario.

You can easily see why a few corrupted sectors really doesn't matter for video information. If we're talking about raw text, however, and you just lost two sectors, that could be very detrimental. If 1 character takes up a single byte, then you just lost 4000 characters of text - and that is almost always a big deal.

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