Mailinglist Archive: opensuse-factory (269 mails)

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[opensuse-factory] Re: Problems reading Video DVDs
Jan Engelhardt <jengelh@xxxxxxx> writes:

On Thursday 2019-09-05 22:37, Berthold Höllmann wrote:

Jan Engelhardt <jengelh@xxxxxxx> writes:

On Wednesday 2019-09-04 23:16, Berthold Höllmann wrote:

Jan Engelhardt <jengelh@xxxxxxx> writes:

On Wednesday 2019-09-04 18:17, Berthold Höllmann wrote:

I did replace the cable now, but that did not fix the problem. I guess
it has to do with libdvdread4 or libdvdcss2, I can burn DVD+RW and
successfully read the burned data with the same drive.

Well if that is your guess, then you can just copy the DVD
with /usr/bin/readcd or /usr/bin/ddrescue to a file,
and then the same problem should occur with said file.

Good point. So it is not the libraries, I can open images of DVD Video
disks and view the content using vlc and mplayer.

Trying to generate the images on this machine aborts dd_rescue finds
only 1073 MBytes, but I can read 4.3GB from DVD+RW disks. What else
could be wrong here?

1073741824 = 1024^3

This value does not appear in the CHS and LBA limitations of bygone
generations
of computer hardware.

But it is a value that .VOB files on DVDs generally do not exceed.
In other words, it does not appear you are copying the disc as a whole
entity;
instead, you are erroneously copying just one file that contains only part
of
the entire feature.

OK, this is somehow consistent with the fact that libdvdcss2 is only
able to determine keys for the first, or first few VOB(s), and fails for
the remaining. The DVD player software (or dd*) are only able to read the
unlocked VOB(s).

That must simply be untrue. dd* does not care whether the files are locked or
not. Unless you have a serious hardware defect (but I more think of it as a
layer-7 problem), there is more than 1 GB to be extracted. If the tools are
used, properly.

But I think the DVD drive does. I insert a video DVD in the drive and
call

LC_ALL=C dd if=/dev/sr0 of=out.iso
dd: error reading '/dev/sr0': Input/output error
2352+0 records in
2352+0 records out
1204224 bytes (1.2 MB, 1.1 MiB) copied, 0.384053 s, 3.1 MB/s
mplayer dvd://
...
(lots of keys on this DVD found, lots more of them not found using libdvdcss2)
...
dd if=/dev/sr0 of=~/ISOs/Hanna.iso
2097151+0 Datensätze ein
2097151+0 Datensätze aus
1073741312 bytes (1,1 GB, 1,0 GiB) copied, 127,892 s, 8,4 MB/s
sudo readcd f=test.iso
No target specified, trying to find one...
Using dev=4,0,0.
Read speed: 16620 kB/s (CD 94x, DVD 12x, BD 3x).
Write speed: 4234 kB/s (CD 24x, DVD 3x, BD 0x).
Capacity: 3005491 Blocks = 6010982 kBytes = 5870 MBytes = 6155 prMB
Sectorsize: 2048 Bytes
Copy from SCSI (4,0,0) disk to file 'test.iso'
end: 3005491
addr: 3005491 cnt: 51
Time total: 549.278sec
Read 6010982,00 kB at 10943,4 kB/sec.
ls -lh test.iso
-rw-r--r-- 1 root root 5,8G 6. Sep 00:57 test.iso

This is the actual sequence of the commands. So in some way libdvdcss2
unlocked the DVD drive in some way, and dd did not read the whole disk.
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