Video_ts compare wonkiness

[devonx]

I have searched these fine forums using many appropriate keywords that I can think of and can find no mention of my issue.

 

I am using Imgburn 2.1.0.0.

 

Whenever I use the Build mode to burn a Video_ts and Audio_ts folders of a dvd they complete without issue. The resulting dvds play in my stand alones and in my computer. When I do a byte to byte comparison of all the files on the dvd and in the Video_ts folder they all match except the VIDEO_TS.IFO and VIDEO_TS.BUP files.

 

For example:

Comparing files VIDEO_TS.BUP and E:\VIDEO_TS\VIDEO_TS.BUP

0000000F: 24 29

00000813: 25 2A

0000081F: 25 2A

0000082B: 7D 82

00000837: DB E0

00000843: 97 9C

0000084F: AE B3

0000085B: 80 85

00000867: 2C 31

00000873: 43 48

0000087F: BD C2

0000088B: 80 85

00000897: E1 E6

000008A3: 9C A1

000008AF: 85 8A

000008BB: E1 E6

000008C7: F5 FA

000008D3: 96 9B

 

Comparing files VIDEO_TS.IFO and E:\VIDEO_TS\VIDEO_TS.IFO

0000000F: 24 29

00000813: 25 2A

0000081F: 25 2A

0000082B: 7D 82

00000837: DB E0

00000843: 97 9C

0000084F: AE B3

0000085B: 80 85

00000867: 2C 31

00000873: 43 48

0000087F: BD C2

0000088B: 80 85

00000897: E1 E6

000008A3: 9C A1

000008AF: 85 8A

000008BB: E1 E6

000008C7: F5 FA

000008D3: 96 9B

I am curious as to what is being changed in those files and why? This doesn't happen to every dvd I burn this way. Just a few. All are DVD-5 and it doesnt matter if 32k padding is on or off. I have had this same thing done by Nero on occasion. So I switched to Imgburn. Since everything seems to be working I have just kept the unedited files for the future (just in case) and gone about my business. I just want to know what is happenning.

 

[devonx]

I just noticed they are all having 5 added to them. So it seems. I didn't do the math on them all.

[devonx]

Just a visual rep of what has changed.

 

 

[LIGHTNING UK!]

32k padding has nothing to do with if it's dvd5 or not, it applies to both (dvd5 + dvd9).

 

If they're all now off by 5 then that's because the program has had to do some padding and now all the title sectors offsets have to be corrected.

[blutach]

In VIDEO_TS.IFO/BUP for example, the first byte that is off is 0x0f. This is the last sector of VMG in the IFO. It is exactly as LUK says. 5 sectors of padding have been added to ensure things end at 32k boundaries.

 

Regards

[devonx]

I guess I do not understand padding then. The files are still the same size. 32k of data has not been appended to anything. Also this happens regardless of the 32k padding option being on or off.

[devonx]

By shifting all of these bytes forward 5 in the ifo and bup what is being accomplished. Is something going to break something? This is mainly what information I am after. I have burned these same dvds over again with a dumb program (nero in iso+udf mode) that just burns the files I want with ISO9660+UDF in their respective VIDEO_TS folder. It does not alter any file though of course I am not guaranteed proper physical locations for the files or order by doing this.

[LIGHTNING UK!]

If it didn't shift the bytes, the offsets in the IFO file (which is what these bytes represent) would then point to the wrong LBA on the disc / within the image.

 

So no it's not breaking anything, it's a MUST or it WOULD be broken - hence it's actually a fix.

[devonx]

Thank you kind sir. I greatly appreciate your time and effort. Going to back that up with some cash as well.

[blutach]

Actually, the files don't grow as you have observed - they are just placed at slightly different places on the DVD (gaps are introduced).

 

This is opposed to packing them in tightly together.

 

Using gaps makes for a safer output.

 

Regards