The state of blu-ray burning in linux is terrible

Thomas Schmitt scdbackup at gmx.net
Tue Jul 30 06:52:11 UTC 2013


Hi,

sorry for breaking the thread. I was not subscribed up to now
and did not yet find an archive that exposes message ids.

--------------------------------------------------------------

It is not that bad with Blu-ray. At least with the backends.
(I am the developer of libburn and use BD-R and BD-RE media daily.)

But wodim (or "cdrecord") out of cdrkit should really be used
only for CD.

The slowliness of BD media comes from their Defect Management
which checkreads the written blocks while they are still present
in the drive's buffer. In case of poor read quality the blocks
get written again or redirected to the Spare Area where the data
get stored in replacement blocks.
This checkreading reduces write speed to at most half of the
nominal speed of drive and BD medium. 

BD-R do Defect Management by default if they are formatted.
BD-RE can only be used formatted and do Defect Management by default.

--------------------------------------------------------------

Original cdrecord out of cdrtools was already discussed in the this
thread. To my knowledge it is fast with BD-R, because it does not
format them. It is not fast with BD-RE, because it uses SCSI command
WRITE(10) which does not allow to override the slow Defect Management.

--------------------------------------------------------------

growisofs out of dvd+rw-tools has a little bug with BD-R.
  https://bugzilla.redhat.com/show_bug.cgi?id=858029
  https://bugzilla.redhat.com/show_bug.cgi?id=868527
It is supposed to be fixed in
  dvd+rw-tools-7.1-13.fc19
The tiny patch is shown in
  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=713016
Workaround is to explicitely format the BD-R before use by
  dvd+rw-format /dev/sr0
or to use option
  -use-the-force-luke=spare:none
when giving an unformatted BD-R to growisofs.

growisofs formats BD-R by default and then uses slow Defect
Management. This can be prevented by option
   -use-the-force-luke=spare:none
growisofs has no means to prevent Defect Management on BD-RE media.

--------------------------------------------------------------

My own programs, libburn based cdrskin and xorriso, do not format
BD-R by default. So they are as fast as with cdrecord.
Other than with cdrecord it is possible to format BD-R on request
  cdrskin -v dev=/dev/sr0 blank=format_if_needed
  xorriso -outdev /dev/sr0 -format as_needed
which makes them capable of slow Defect Management.
Other than growisofs and cdrecord, cdrskin and xorriso offer the
opportunity to disable Defect Management on formatted BD-R and
on BD-RE
  cdrskin stream_recording=on ...cdrecord-like-burn-options...
  xorriso -stream_recording on ...xorriso-burn-commands...
This is especially helpful with 2x BD-RE, which elsewise need
an awfully long time to write their capacity of 22.5 GiB.


Have a nice day :)

Thomas



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