While backing up my collection I came across a disc (Finnish edition of SpongeBob RoundPants) that displayed no errors if converted to MKV straight from the disc, but threw several errors if the same thing was done from an .iso backup made in MakeMKV. I then made an ISO through ddrescue and that one did not display any errors either. Comparing the two dumps in a hex editor, I found entire chunks of data in the ddrescue dump that were simply missing in the MakeMKV one:
There are also a few other DVDs (such as the UK release of SpongeBob The Great Sleigh Race) where the ISO backup completely fails on MakeMKV around RipGuard spots, but works without troubles through ddrescue.
Logs from the MakeMKV RoundPants ISO:
003007:0000 Using direct disc access mode
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 7 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 8 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 9 at "_8Y~gp]N83/.*7Rw:121263199
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137206
003003:0000 Signature is invalid in IFO file
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137252
001003:0020 DEBUG: Code 9 at u*9'>(mDm1Nfak:29393631
001003:0020 DEBUG: Code 0 at +$_A@/HAE>Gu*s(~':121263245
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 10 at "_8Y~gp]N83/.*7Rw:121263199
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137206
003003:0000 Signature is invalid in IFO file
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137252
001003:0020 DEBUG: Code 10 at u*9'>(mDm1Nfak:29393631
001003:0020 DEBUG: Code 0 at +$_A@/HAE>Gu*s(~':121263245
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 11 at "_8Y~gp]N83/.*7Rw:121263199
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137206
003003:0000 Signature is invalid in IFO file
001003:0020 DEBUG: Code 0 at u*9'>(mDm1Nfak:213137252
001003:0020 DEBUG: Code 11 at u*9'>(mDm1Nfak:29393631
001003:0020 DEBUG: Code 0 at +$_A@/HAE>Gu*s(~':121263245
Launching C:\Program Files (x86)\MakeMKV\mmgplsrv64.exe
001003:0020 DEBUG: Code 118095996 at t@0qOpXwqs/,9~q]A&p&nou:29394183
001003:0020 DEBUG: Code 0 at t@0qOpXwqs/,9~q]A&p&nou:121263590
001003:0020 DEBUG: Code 1 at n[Zy%v?9:72#^FwvnV]o:29394689
001003:0020 DEBUG: Code 3221225649 at 6Zll4j:o?e20(+mh?z$:wLD:29394919
001003:0020 DEBUG: Code 3221225649 at t@0qOpXwqs/,9~q]A&p&nou:213130145
001003:0020 DEBUG: Code 3221225480 at 6Zll4j:o?e20(+mh?z$:wLD:121262509
001003:0020 DEBUG: Code 3221225480 at t@0qOpXwqs/,9~q]A&p&nou:29394183
001003:0020 DEBUG: Code 0 at t@0qOpXwqs/,9~q]A&p&nou:121263590
001003:0020 DEBUG: Code 0 at 3alQd2hOf!%UQ+:29397104
003038:0000 Cells 9-12 were removed from title end
003028:0000 Title #1 was added (8 cell(s), 1:17:17)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #2 was added (4 cell(s), 0:12:37)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #3 was added (4 cell(s), 0:12:32)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #4 was added (4 cell(s), 0:12:24)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #5 was added (4 cell(s), 0:12:31)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #6 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #7 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #8 was added (4 cell(s), 0:12:39)
003038:0000 Cells 3-5 were removed from title end
003028:0000 Title #9 was added (2 cell(s), 0:11:38)
003038:0000 Cells 9-12 were removed from title end
003028:0000 Title #10 was added (8 cell(s), 1:17:17)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #11 was added (4 cell(s), 0:12:37)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #12 was added (4 cell(s), 0:12:32)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #13 was added (4 cell(s), 0:12:24)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #14 was added (4 cell(s), 0:12:31)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #15 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #16 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #17 was added (4 cell(s), 0:12:39)
003038:0000 Cells 3-5 were removed from title end
003028:0000 Title #18 was added (2 cell(s), 0:11:38)
003038:0000 Cells 9-12 were removed from title end
003028:0000 Title #19 was added (8 cell(s), 1:17:17)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #20 was added (4 cell(s), 0:12:37)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #21 was added (4 cell(s), 0:12:32)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #22 was added (4 cell(s), 0:12:24)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #23 was added (4 cell(s), 0:12:31)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #24 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #25 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #26 was added (4 cell(s), 0:12:39)
003038:0000 Cells 3-5 were removed from title end
003028:0000 Title #27 was added (2 cell(s), 0:11:38)
003038:0000 Cells 9-12 were removed from title end
003028:0000 Title #28 was added (8 cell(s), 1:17:17)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #29 was added (4 cell(s), 0:12:37)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #30 was added (4 cell(s), 0:12:32)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #31 was added (4 cell(s), 0:12:24)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #32 was added (4 cell(s), 0:12:31)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #33 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #34 was added (4 cell(s), 0:12:38)
003038:0000 Cells 5-5 were removed from title end
003028:0000 Title #35 was added (4 cell(s), 0:12:39)
003038:0000 Cells 3-5 were removed from title end
003028:0000 Title #36 was added (2 cell(s), 0:11:38)
003038:0000 Cells 2-2 were removed from title end
003028:0000 Title #37 was added (1 cell(s), 0:04:50)
003038:0000 Cells 2-2 were removed from title end
003028:0000 Title #38 was added (1 cell(s), 0:06:35)
003038:0000 Cells 2-2 were removed from title end
003028:0000 Title #39 was added (1 cell(s), 0:00:15)
003038:0000 Cells 2-2 were removed from title end
003028:0000 Title #40 was added (1 cell(s), 0:03:37)
003038:0000 Cells 2-2 were removed from title end
003028:0000 Title #41 was added (1 cell(s), 0:14:11)
003028:0000 Title #42 was added (1 cell(s), 0:00:04)
Title skip vts=8 pgcn=1
003014:0000 Title #44 in broken titleset was skipped
003014:0000 Title #45 in broken titleset was skipped
003014:0000 Title #46 in broken titleset was skipped
003027:0000 Title #10 in VTS 1 is equal to title #01 and was skipped
003027:0000 Title #19 in VTS 1 is equal to title #01 and was skipped
003027:0000 Title #28 in VTS 1 is equal to title #01 and was skipped
003027:0000 Title #18 in VTS 1 is equal to title #09 and was skipped
003027:0000 Title #27 in VTS 1 is equal to title #09 and was skipped
003027:0000 Title #36 in VTS 1 is equal to title #09 and was skipped
003034:0000 Audio stream #0 in title #42 looks empty and was skipped
003034:0000 Audio stream #1 in title #42 looks empty and was skipped
003034:0000 Audio stream #2 in title #42 looks empty and was skipped
003034:0000 Audio stream #3 in title #42 looks empty and was skipped
005011:0000 Operation successfully completed
Logs from the ddrescue RoundPants ISO:
003007:0000 Using direct disc access mode
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 7 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 8 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 9 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 10 at "_8Y~gp]N83/.*7Rw:121263199
DEBUG: Code 0 at `.5&w{UQ9+(B={!RmP?:121261704
DEBUG: Code 11 at "_8Y~gp]N83/.*7Rw:121263199
Launching C:\Program Files (x86)\MakeMKV\mmgplsrv64.exe
003028:0000 Title #1 was added (12 cell(s), 1:29:05)
003028:0000 Title #2 was added (5 cell(s), 0:12:37)
003028:0000 Title #3 was added (5 cell(s), 0:12:32)
003028:0000 Title #4 was added (5 cell(s), 0:12:24)
003028:0000 Title #5 was added (5 cell(s), 0:12:31)
003028:0000 Title #6 was added (5 cell(s), 0:12:38)
003028:0000 Title #7 was added (5 cell(s), 0:12:38)
003028:0000 Title #8 was added (5 cell(s), 0:12:39)
003028:0000 Title #9 was added (5 cell(s), 0:12:32)
003028:0000 Title #10 was added (12 cell(s), 1:29:05)
003028:0000 Title #11 was added (5 cell(s), 0:12:37)
003028:0000 Title #12 was added (5 cell(s), 0:12:32)
003028:0000 Title #13 was added (5 cell(s), 0:12:24)
003028:0000 Title #14 was added (5 cell(s), 0:12:31)
003028:0000 Title #15 was added (5 cell(s), 0:12:38)
003028:0000 Title #16 was added (5 cell(s), 0:12:38)
003028:0000 Title #17 was added (5 cell(s), 0:12:39)
003028:0000 Title #18 was added (5 cell(s), 0:12:32)
003028:0000 Title #19 was added (12 cell(s), 1:29:05)
003028:0000 Title #20 was added (5 cell(s), 0:12:37)
003028:0000 Title #21 was added (5 cell(s), 0:12:32)
003028:0000 Title #22 was added (5 cell(s), 0:12:24)
003028:0000 Title #23 was added (5 cell(s), 0:12:31)
003028:0000 Title #24 was added (5 cell(s), 0:12:38)
003028:0000 Title #25 was added (5 cell(s), 0:12:38)
003028:0000 Title #26 was added (5 cell(s), 0:12:39)
003028:0000 Title #27 was added (5 cell(s), 0:12:32)
003028:0000 Title #28 was added (12 cell(s), 1:29:05)
003028:0000 Title #29 was added (5 cell(s), 0:12:37)
003028:0000 Title #30 was added (5 cell(s), 0:12:32)
003028:0000 Title #31 was added (5 cell(s), 0:12:24)
003028:0000 Title #32 was added (5 cell(s), 0:12:31)
003028:0000 Title #33 was added (5 cell(s), 0:12:38)
003028:0000 Title #34 was added (5 cell(s), 0:12:38)
003028:0000 Title #35 was added (5 cell(s), 0:12:39)
003028:0000 Title #36 was added (5 cell(s), 0:12:32)
003028:0000 Title #37 was added (2 cell(s), 0:04:50)
003028:0000 Title #38 was added (2 cell(s), 0:06:35)
003028:0000 Title #39 was added (2 cell(s), 0:00:15)
003028:0000 Title #40 was added (2 cell(s), 0:03:37)
003028:0000 Title #41 was added (2 cell(s), 0:14:11)
005011:0000 Operation successfully completed
This makes me believe MakeMKV's RipGuard implementation may be slightly flawed. In addition to this, all ripguard spots are filled in with "EF" and occassionally a string saying "READ ERROR" which is honestly quite strange.