[SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

lonsdaleite · 2020-12-17 19:32:13

Recently I got a DVD writer/player which I am attempting to use to playback DVDs.

When using VLC I found that for the first DVD I tried I could only play one of several episodes - if I tried another then VLC would return to the cone screen.

I set an output directory for VLC's logs and read them to find this output from libdvdnav:

dvdnav debug: Get key for /VIDEO_TS/VIDEO_TS.VOB at 0x0000aae1
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_01_0.VOB at 0x0000ab19
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_01_1.VOB at 0x0000ac74
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_02_0.VOB at 0x0000b195
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_02_1.VOB at 0x0000b199
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_03_0.VOB at 0x0000cd93
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_03_1.VOB at 0x0000cd97
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_04_0.VOB at 0x0005249a
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_04_1.VOB at 0x0005249e
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_05_0.VOB at 0x00097555
dvdnav warning: Error cracking CSS key for /VIDEO_TS/VTS_05_0.VOB (0x00097555)
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_05_1.VOB at 0x00097559
dvdnav warning: Error cracking CSS key for /VIDEO_TS/VTS_05_1.VOB (0x00097559)
dvdnav debug: Elapsed time 0
dvdnav debug: Get key for /VIDEO_TS/VTS_06_0.VOB at 0x000dc650
dvdnav warning: Error cracking CSS key for /VIDEO_TS/VTS_06_0.VOB (0x000dc650)
...

It goes on for quite a while, but every key following this fails to be cracked.

I tried a few other DVDs and found again that only some keys were cracked but most failed.

I tried using the DVD player on a Macbook to play back the same DVDs I tried here, and the playback worked fine.

I then tried to use MPlayer and ran into the same errors, though this time from libdvdread, saying that they could not read the titles which corresponded to those whose keys were not cracked:

libdvdread: Can't seek to block 541777
libdvdread: Can't seek to block 541777
libdvdread: Can't seek to block 541777
libdvdread: Invalid IFO for title 4 (VTS_04_0.IFO)

I have installed (and reinstalled) through pacman libdvdcss, libdvdread, and libdvdnav.
I have done a full system update (pacman -Syu).
I have also deleted ~/.dvdcss each time I try something new.

Last edited by lonsdaleite (2020-12-21 19:42:50)

seth · 2020-12-17 21:38:25

Check dmesg whether there're I/O errors (ie. the drive has simply problems to read the disc)
Do always the same vobs fail or always the ones you try to play "later"?

lonsdaleite · 2020-12-17 22:00:23

For a given DVD, which vobs work and which fail are consistent. Generally the first few work, though not always - for one of the DVDs, only one of the episodes halfway through works.

I could not find anything in the output of dmesg which looked like an error. I did a case sensitive search for lines with "ROM" on the output of dmesg with a DVD in; it yielded:

pci 0000:28:00.0: Video device with shadowed ROM at [mem 0x000c0000-0x000dffff]
scsi 10:0:0:0: CD-ROM            HL-DT-ST DVDRAM SP80NB80  RC00 PQ: 0 ANSI: 0
cdrom: Uniform CD-ROM driver Revision: 3.20
amdgpu 0000:28:00.0: No more image in the PCI ROM
sr 10:0:0:0: Attached scsi CD-ROM sr0

I'm not familiar reading the output of dmesg, so is there anything in it besides this I ought to look for?

seth · 2020-12-17 22:10:36

dmesg | grep sense

Sounds as if the inner rings work and stuff starts to fail on outer rings - do you have problems w/ unencrypted DVDs?

lonsdaleite · 2020-12-18 00:32:45

Running:

dmesg | grep sense

yields nothing.

I don't believe I have any unencrypted DVDs that aren't blank.

seth · 2020-12-18 07:24:52

Ah, blast. Was too late (the actual token is "Sense")

dmesg | grep -iC5 sense

lonsdaleite · 2020-12-18 17:00:59

Unfortunately, running

dmesg | grep -iC5 sense

with a DVD in also yielded nothing.

Last edited by lonsdaleite (2020-12-18 17:01:59)

seth · 2020-12-18 23:03:08

After trying to play it? (this would reveal mode sense errors like DRDY)
Run "dmesg -w" and try to play a dvd (until it fails) and check whether you get some messages from that.

I don't like™ that the first chapters work since that smells like the inner rings are good but when the drive spins faster for the outer rings, you end up w/ errors.

lonsdaleite · 2020-12-19 02:22:07

dmesg -w

does not spit out any errors (just audits of the network daemon) after trying unsuccessfully to play certain parts of the DVD.

I'm less inclined to think hardware issue given that these DVDs and player work perfectly well on the Macbook I used as a test, that dmesg outputs no errors, and that the first errors which occur are related to errors in cracking CSS keys and seem to originate in libdvdcss. Though I really have no understanding of how optical media works, so I will defer to whatever suggestions you have.

lonsdaleite · 2020-12-19 04:58:24

Ok, so I tried playing one of the DVDs using my same DVD reader on a machine running Ubuntu and... same issue as encountered here. However, that machine has a native DVD player - when I use that, the DVD runs fine. I guess the issue is with the player itself. Though I have no clue why that would be given that dmesg outputs no errors and the discrete player worked on a Macbook.

seth · 2020-12-19 07:43:10

What is " a native DVD player"?

Lone_Wolf · 2020-12-19 15:38:02

What connection does the portable one use ?
If unsure, post brand and model .

lonsdaleite · 2020-12-19 19:20:47

By "native DVD player," I just meant a different DVD player connected by SATA and not USB integrated into the case.

The portable player I was using is connected via USB, it's the "LG Ultra Slim Portable DVD Writer," and its model number is sp80nb80.

seth · 2020-12-20 20:35:05

Wild guess, try to disable USB autosuspend (the drive might stumble when it wakes up)
https://wiki.archlinux.org/index.php/Po … utosuspend
"usbcore.autosuspend=-1" will globally disable it but nb. that userspace powermanagement tools can and will alter this at runtime.

lonsdaleite · 2020-12-21 19:41:48

So, bizarrely, I think the issue was specific to the DVD player. A person had a spare Apple Superdrive that they were not going to use, and with a quick hack, it worked perfectly. I will probably return the malfunctioning DVD player.

Thanks for the help!

Arch Linux

#1 2020-12-17 19:32:13

[SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#2 2020-12-17 21:38:25

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#3 2020-12-17 22:00:23

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#4 2020-12-17 22:10:36

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#5 2020-12-18 00:32:45

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#6 2020-12-18 07:24:52

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#7 2020-12-18 17:00:59

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#8 2020-12-18 23:03:08

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#9 2020-12-19 02:22:07

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#10 2020-12-19 04:58:24

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#11 2020-12-19 07:43:10

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#12 2020-12-19 15:38:02

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#13 2020-12-19 19:20:47

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#14 2020-12-20 20:35:05

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

#15 2020-12-21 19:41:48

Re: [SOLVED] libdvdcss can crack some but not all CSS keys for all DVDs I

Board footer