Help needed in recovering the video of a surgery

The following is a duplicate of a posting I have made on the ubuntu forums. However I feel that here, it would be better addressed and I really hope you can help me:

I am in need of immediate assistance to recover some data from a DVD. To make a long story short:
My wife had surgery a couple of days ago, and it was recorded on a DVD recorder in the OR (Operating Room) kinda like the way footage is recorded from a security camera. Hence I don’t have the file to burn it again, I cannot choose the DVD writing speed, or apply any technique regarding RECORDING the data.

The problem is that the DVD which is the MASTER DVD (no other backup and no other alternative for having the video files exists, short of putting my wife in surgery again) is unreadable on anything except the machine that recorded it (which rules out physical damage to the disk). Tried it on 4 different computers, and nothing. On the windows machine (yeah I know, God forbid, but I was desperate ) I’ve tried ISO Buster and CDRoller. ISO Buster "pretends to work very hard, it produces images of the tracks, but the ISOs are empty. CDRoller… doesn’t even bother.

In Linux (Kubuntu 9.04) I get the following output when inserting the DVD into the drive (dmesg |tail -n20)

[569918.067561] cdrom: This disc doesn’t have any tracks I recognize!
[569925.354157] sr 5:0:0:0: [sr0] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[569925.354166] sr 5:0:0:0: [sr0] Sense Key : Medium Error [current]
[569925.354173] Info fld=0x0
[569925.354176] sr 5:0:0:0: [sr0] Add. Sense: L-EC uncorrectable error
[569925.354184] end_request: I/O error, dev sr0, sector 0
[569925.354192] Buffer I/O error on device sr0, logical block 0
[569932.353076] sr 5:0:0:0: [sr0] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[569932.353084] sr 5:0:0:0: [sr0] Sense Key : Medium Error [current]
[569932.353092] Info fld=0x0
[569932.353094] sr 5:0:0:0: [sr0] Add. Sense: L-EC uncorrectable error
[569932.353102] end_request: I/O error, dev sr0, sector 0
[569932.353110] Buffer I/O error on device sr0, logical block 0

I’ve tried to copy the content with dd even using the noerror option, but again failure.

When using dvdisaster I get a “Reading aborted Invalid or damaged ecc file” error at the very beginning when I try to read the DVD. (Even after editing the preferences to ignore fatal errors). Upon further tweaking I have ONCE managed to read the disk, but it reports 100% Unreadable / skipped sectors, and when I try to create the image it aborts with “unrecoverable error” and we’re back at square one.

I have tried dares, dares_qt, dd_rescue and all of them are reporting only 2Kb of working data.

Dares-qt:

dares 0.6.5 started at Tue May 19 08:54:43 2009
opening image /dev/cdrom: ok
Could not load file magic database file ‘magic’, using default database
, 0: Warning: using regular magic file `/etc/magic’
finished: scanned 0 2K blocks, found 0 files

dd_rescue

dd_rescue -v /dev/cdrom /media/Storage/project/operatie.iso
dd_rescue: (info): about to transfer 0.0 kBytes from /dev/cdrom to /media/Storage/project/operatie.iso
dd_rescue: (info): blocksizes: soft 65536, hard 512
dd_rescue: (info): starting positions: in 0.0k, out 0.0k
dd_rescue: (info): Logfile: (none), Maxerr: 0
dd_rescue: (info): Reverse: no , Trunc: no , interactive: no
dd_rescue: (info): abort on Write errs: no , spArse write: if err
dd_rescue: (info): ipos: 0.0k, opos: 0.0k, xferd: 0.0k
errs: 0, errxfer: 0.0k, succxfer: 0.0k
+curr.rate: 0kB/s, avg.rate: 0kB/s, avg.load: 0.0%
dd_rescue: (info): /dev/cdrom (0.0k): EOF

I have tried to view the content of the first few sectors, and the only intelligible thing I’ve managed to extract is a line that says “Sonata DVD-R”, which upon further reading seems to be a kind of tamper proof format used in sensitive areas to prevent altering the video content.

Moreover, I cannot mount the disk. Here is the output of the mount command:

sudo mount -t iso9660 /dev/scd0 /media/cdrom

mount: block device /dev/sr0 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sr0,
missing codepage or helper program, or other error
(could this be the IDE device where you in fact use
ide-scsi so that sr0 or sda or so is needed?)
In some cases useful info is found in syslog - try
dmesg | tail or so

and here’s once more the output of dmesg | tail, this time from the failed mount attempt:

[ 55.042894] cdrom: This disc doesn’t have any tracks I recognize!
[ 61.672172] Marking TSC unstable due to cpufreq changes
[ 62.144028] Clocksource tsc unstable (delta = -211176557 ns)
[ 402.289395] sr 5:0:0:0: [sr0] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[ 402.289404] sr 5:0:0:0: [sr0] Sense Key : Medium Error [current]
[ 402.289411] Info fld=0x10
[ 402.289414] sr 5:0:0:0: [sr0] Add. Sense: L-EC uncorrectable error
[ 402.289422] end_request: I/O error, dev sr0, sector 64
[ 402.289459] isofs_fill_super: bread failed, dev=sr0, iso_blknum=16, block=16

I get the same errors when attempting to mount it as a udf filesystem.

In ISO Buster I have managed to view the structure of the DVD: It consists of 6 tracks, on track 4 which is about 600 MB, there is a folder which looks like a regular DVD (with VideoTS and AudioTS and a couple of tracks that are a couple of hundred MB each). There is also Track 6, which has 2 GB but there is no subdirectory or file in its structure.

I have also tried viewing it “as is” in VLC Media Player, but no luck there too.

So, to sum it up: the disk I have is the MASTER disk, the only one that gets to be recorded “LIVE”, in the operating room, with video feed from the miniature camera that captures the procedure itself. No way am I asking my wife to repeat surgery all over again. I have tried beginner and intermediate methods of recovering the data from the disk, which, I say again, CAN BE VIEWED on the master recorder (the one in the OR), which rules out physical damage to the disk, or loss of data due to faulty recording. I suspect one of two things: either Track 0 of the disk is written in an unorthodox way, to prevent tampering or duplication, or the file format is a bit strange altogether.

Thank you in advance for your assistance.

Wydarr,

I have no easy answer for you, but since no one else has responded in three days, I thought I’d at least share how I investigate uncommmon disc structures. I rely on Easy Media Creator 7’s Disc and Device Utility. This utility will usually come up with the track structure of the disc and allow me to create an image of each track. After that I go in with a hex editor and try to make heads or tails out of what’s there.

The first thing I would check is the first track to see if it looks anything like a normal ISO/UDF track. Failing that I would try to determine whether the disc has a UDF Virtual Allocation Table.

The fact that you found a folder on track 4 “which looks like a regular DVD (with VideoTS and AudioTS and a couple of tracks that are a couple of hundred MB each)” is a very good sign. I would go in and decipher that “folder” section and look for start addresses and lengths for the key DVD files. If nothing else, you might be able to extract the data into individual files, give the files appropriate names and see if your DVD player software will play them.

If you can create image files of the individual tracks, but find that trying to interpret them is over your head, I’d be willing to take a look at them if you sent them to me.

Dr. Joe