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DVD number of sectors off by one?

markfilipak

markfilipak

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Kindly excuse me if this has been addressed -- my search was rejected, words too common...
It appears that AnyDVD HD is reporting number of sectors off by one. For a particular DVD,
Windows Explorer reports 7,939,278,848 bytes (i.e., 3876601 sectors),
AnyDVD HD reports 3876602 sectors.
 
Maybe just a rounding issue? Don't even know how to calculate sectors lol
 
Hi. There is no rounding.

There's 2048 bytes/sector. Windows reports 7,939,278,848 bytes. That's 3876601 sectors.
AnyDVD HD reports 3876602 sectors. That's off by one.

"Off by one" is a common programming error.
 
markfilipak said:
Hi. There is no rounding.

There's 2048 bytes/sector. Windows reports 7,939,278,848 bytes. That's 3876601 sectors.
AnyDVD HD reports 3876602 sectors. That's off by one.

"Off by one" is a common programming error.
Click to expand...
Either in Windows or AnyDVD. It is all so confusing. "ReadCapacity" lets the drive report the LBA of the last sector. To get the number of sectors, you need to add 1 (LBA starts with 0).
But it doesn't matter, nobody cares (except you :) )
 
Hey James!
James said:
Either in Windows or AnyDVD. It is all so confusing. "ReadCapacity" lets the drive report the LBA of the last sector. To get the number of sectors, you need to add 1 (LBA starts with 0).
But it doesn't matter, nobody cares (except you :) )
Click to expand...
Hahaha... You're right, there! However, 1, 'off by one' may be a lead to other errors (...or not), and 2, it's not confusing: Your LBA 'count' is really an index into serial data, so it begins at zero. LBs (logical blocks) are not numbered, they just exist as a serial sequence.

PS: A total count is always ending_index+1.
 
Last edited:
markfilipak said:
Hi. There is no rounding.

There's 2048 bytes/sector. Windows reports 7,939,278,848 bytes. That's 3876601 sectors.
AnyDVD HD reports 3876602 sectors. That's off by one.

"Off by one" is a common programming error.
Click to expand...
It's 2048 user data but the RAW sectors of a DVD are different. I can't recall for CD it's 2352. Not sure that is relevant for this as not many drives can even read raw sectors (I have a few that do).

If it's a common programming error what does that mean for ripping DVDs to an ISO? Does it make any difference?
 
I have ripped thousands too. Except maybe for the occasional "can't rip" situation, off-by-one seems to make no difference. I noticed it because I write reviews and the number of bytes can be important for differentiating between releases of the same title.

The only people to whom it's important is me and James. Now that I know about it, I'm ignoring it. ...:)
 
TubeBar said:
It's 2048 user data but the RAW sectors of a DVD are different. I can't recall for CD it's 2352. Not sure that is relevant for this as not many drives can even read raw sectors (I have a few that do).

If it's a common programming error what does that mean for ripping DVDs to an ISO? Does it make any difference?
Click to expand...
So, underneath UDF there's another file system with it's own sector architecture? I find that extremely hard to believe.
 
Thanks for the explanation. I'll leave it to you and James since you're the DVD experts ;)
 
Well, I know a bit. I'm a scientist-engineer with video experience, also. But you should consider James to be the only expert here.
 
markfilipak said:
Kindly excuse me if this has been addressed -- my search was rejected, words too common...
It appears that AnyDVD HD is reporting number of sectors off by one. For a particular DVD,
Windows Explorer reports 7,939,278,848 bytes (i.e., 3876601 sectors),
AnyDVD HD reports 3876602 sectors.
Click to expand...
This is a strange off-by-one. Let me explain...

3876601 sectors would mean that a final sector index is 3876600 (i.e., one less than the number of sectors). AnyDVD HD reports 3876602 (i.e. one greater than the number of sectors). So, James's number of sectors is 2 greater than what would be expected for an off-by-one error.

I just think that's unexplained/unexplainable, and a reason for concern.
 
markfilipak said:
Well, I know a bit. I'm a scientist-engineer with video experience, also. But you should consider James to be the only expert here.
Click to expand...
Vert impressive :)

Sure James knows this software inside and out, he's been working on it for God knows how long. I get it.
 
markfilipak said:
This is a strange off-by-one. Let me explain...

3876601 sectors would mean that a final sector index is 3876600 (i.e., one less than the number of sectors). AnyDVD HD reports 3876602 (i.e. one greater than the number of sectors). So, James's number of sectors is 2 greater than what would be expected for an off-by-one error.

I just think that's unexplained/unexplainable, and a reason for concern.
Click to expand...
Luckily it's adding a sector, so in creating an ISO wouldn't it just have some null zeros at the end instead of being cut off? Not really a big issue if that's the case.

If on the other hand it was cutting off data that's a problem.
 
I doubt any of that is a problem. The actual rip sizes I've encountered have been correct. I think this issue is merely with the report shown when AnyDVD displays what it found prior to ripping. Nothing to fear.
 
markfilipak said:
I doubt any of that is a problem. The actual rip sizes I've encountered have been correct. I think this issue is merely with the report shown when AnyDVD displays what it found prior to ripping. Nothing to fear.
Click to expand...
OK great :)
 
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