Jul 272016

x264 logoSince I’ve been doing a bit of Anime batch video transcoding with x264 and x265 in the last few months, I thought I’d document this for myself here. My goal was to loop over an arbitrary amount of episodes and just batch-transcode them all at once. And that on three different operating systems: Windows (XP x64), Linux (CentOS 6.8 x86_64) and FreeBSD 10.3 UNIX, x86_64. Since I’ve started to split the work across multiple machines, I lost track of what was where and which machine finished what, and when.

So I thought, why not let the loop send me a small notification email upon completion? And that’s what I did. On Linux and UNIX this relies on the bash shell and the mailx command. Please note that I’m talking about [Heirloom mailx], not some other mail program by the same name! I’m mentioning this, because there is a different default mailx on FreeBSD, that won’t work for this. That’s why I put alias mailx='/usr/local/bin/mailx' in my ~/.bash_profile on that OS after installing the right program to make it the default for my user.

On Windows, my loops depend on my own [colorecho] command (you can replace that with cmds’ ECHO if you want) as well as the command line mailer [blat]. Note that, if you need to use SSL/TLS encryption when mailing, blat can’t do that. A suitable replacement could be [mailsend]. Please note, that mailsend does not work on Windows XP however.

In the x265 case, avconv (from the [libav] package) is required on all platforms. You can get my build for Windows [here]. If you don’t like it, the wide-spread [ffmpeg] can be a suitable drop-in replacement.

Now, when setting up blat on Windows, make sure to run blat -help first, and learn the details about blat -install. You need to run that with certain parameters to set it up for your SMTP mail server. For whatever reason, blat reads some of that data from the registry (ew…), and blat -install will set that up for you.

Typically, when I transcode, I do so on the elementary streams rather than .mkv files directly. So I’d loop through some source files and extract the needed streams. Let’s say we have “A series – episode 01.mkv” and some more, all the way up to “A series – episode 13.mkv”, then, assuming track #0 is the video stream…

On Windows:

FOR %I IN (01,02,03,04,05,06,07,08,09,10,11,12,13) DO mkvextract tracks "A series - episode %I.mkv" ^

On Linux/UNIX:

for i in {01..13}; do mkvextract tracks "A series - episode $i.mkv" 0:$i/video.h264; done

mkvextract will create the non-existing subfolder for us, and a x264 transcoding loop would then look like this on Windows:

expand/collapse source code
 (01,02,03,04,05,06,07,08,09,10,11,12,13) DO "c:\Program Files\VFX\x264cli\x264-10b.exe" --fps ^
 24000/1001 --preset veryslow --tune animation --open-gop -b 16 --b-adapt 2 --b-pyramid normal -f ^
 -2:0 --bitrate 2500 --aq-mode 1 -p 1 --slow-firstpass --stats %I\v.stats -t 2 --no-fast-pskip ^
 --cqm flat --non-deterministic --demuxer lavf %I\video.h264 -o %I\pass1.264 & colorecho "Pass 1 ^
 done for Episode %I/"!EPNUM!" of "!SERIES!"" 10 & ECHO. & ^
 "c:\Program Files\VFX\x264cli\x264-10b.exe" --fps 24000/1001 --preset veryslow --tune animation ^
 --open-gop -b 16 --b-adapt 2 --b-pyramid normal -f -2:0 --bitrate 2500 --aq-mode 1 -p 2 --stats ^
 %I\v.stats -t 2 --no-fast-pskip --cqm flat --non-deterministic --demuxer lavf %I\video.h264 -o ^
 %I\pass2.264 & colorecho "Pass 2 done for Episode %I/"!EPNUM!" of "!SERIES!"" 10) & echo !SERIES! ^
 transcoding complete | blat - -t "myself@another.mailhost.com" -c "myself@mailhost.com" -s "x264 ^
 notification from !MACHINE!" & SET MACHINE= & SET EPNUM= & SET SERIES="

Note that I always write all the iteration out in full here. That’s because cmd can’t do loops with leading zeroes in the iterator. The reason for this is that those source files usually have them in their lower episode numbers. If it wasn’t 01,02, … ,12,13, but 1,2, … ,12,13 instead, you could do FOR /L %I IN (1,1,13) DO. But this isn’t possible in my case. Even if elements need alphanumeric names like here,  FOR %I IN (01,02,03,special1,special2,ova1,ova2) DO, you still won’t need that syntax on Linux/UNIX because the bash can have iterator groups like for i in {{01..13},special1,special2,ova1,ova2}; do. Makes me despise the cmd once more. ;)


Ah, according to [this], you can actually do something like cmd /V /C "FOR /L %I IN (1,1,13) DO (SET "fI=00%I" & echo "!fI!:~-2")", holy shit. It actually works and gives you leading zeroes. :~-2 for 2 digits, :~-3 for three. Expand fI for more in this example. I mean, what is this even? Some number formatting magic? I probably don’t even wanna know… Couldn’t find any way of having several groups for the iterator however. Meh. Still don’t like it.

So, well, it’s like this on Linux/UNIX:

expand/collapse source code
(export MACHINE=BEAST EPNUM=13 SERIES='AnimeX'; for i in {01..13}; do nice -n19 x264 --fps \
24000/1001 --preset veryslow --tune animation --open-gop -b 16 --b-adapt 2 --b-pyramid normal -f \
-2:0 --bitrate 2500 --aq-mode 1 -p 1 --slow-firstpass --stats $i/v.stats -t 2 --no-fast-pskip \
--cqm flat --non-deterministic --demuxer lavf $i/video.h264 -o $i/pass1.264 && echo && echo -e \
"\e[1;31m`date +%H:%M`, pass 1 done for episode $i/$EPNUM of $SERIES\e[0m" && echo && nice -n19 \
x264 --fps 24000/1001 --preset veryslow --tune animation --open-gop -b 16 --b-adapt 2 --b-pyramid \
normal -f -2:0 --bitrate 2500 --aq-mode 1 -p 2 --stats $i/v.stats -t 2 --no-fast-pskip --cqm flat \
--non-deterministic --demuxer lavf $i/video.h264 -o $i/pass2.264 && echo && echo -e \
"\e[1;31m`date +%H:%M`, pass 2 done for episode $i/$EPNUM of $SERIES\e[0m" && echo; done && echo \
"$SERIES transcoding complete" | mailx -s "x264 notification from $MACHINE" -r \
"myself@mailhost.com" -c "myself@another.mailhost.com" -S smtp-auth="login" -S \
smtp="smtp.mailhost.com" -S smtp-auth-user="myuser" -S smtp-auth-password="mysecurepassword" \

The variable $MACHINE or %MACHINE%/!MACHINE! specifies the machines’ host name. This will be noted in the email, so I know which machine just completed something. $EPNUM – or %EPNUM%/!EPNUM! on Windows – is used for periodic updates on the shell. The output would be like “Pass 1 done for Episode 07/13 of AnimeX” in green on Windows and bold red on Linux/UNIX (just change the color to your liking).

Finally, $SERIES aka %SERIES%/!SERIES! would be the series’ name. So say, the UNIX machine named “BEAST” above is done with this loop. The email would come with the subject line “x264 notification from BEAST” and would read “AnimeX transcoding complete” in plain text. That’s all.

Please note, that cmd batch on Windows is extremely creepy. Every whitespace (especially the leading ones when doing multi-line like this for display) needs to be exactly where it is. The same goes for double quotes where you might think they aren’t needed. They are! Also, this needs delayed variable expansion once again, which is why we see variables like !EPNUM! instead of %EPNUM% and why it’s called in a subshell by running cmd /V /C.

On Linux/UNIX we don’t need to rely on some specific API like cmds’ SetConsoleTextAttribute() to print colors, as most terminals understand ANSI color codes.

And this is what it looks like for x265:


expand/collapse source code
 (01,02,03,04,05,06,07,08,09,10,11,12,13) DO avconv -r 24000/1001 -i %I\video.h264 -f yuv4mpegpipe ^
 -pix_fmt yuv420p -r 24000/1001 - 2>NUL | "C:\Program Files\VFX\x265cli-mb\x265.exe" - --y4m -D 10 ^
 --fps 24000/1001 -p veryslow --pmode --pme --open-gop --ref 6 --bframes 16 --b-pyramid --bitrate ^
 2500 --rect --amp --aq-mode 3 --no-sao --qcomp 0.75 --no-strong-intra-smoothing --psy-rd 1.6 ^
 --psy-rdoq 5.0 --rdoq-level 1 --tu-inter-depth 4 --tu-intra-depth 4 --ctu 32 --max-tu-size 16 ^
 --pass 1 --slow-firstpass --stats %I\v.stats --sar 1 --range full -o %I\pass1.h265 & colorecho ^
 "Pass 1 done for Episode %I/"!EPNUM!" of "!SERIES!"" 10 & ECHO. & avconv -r 24000/1001 -i ^
 %I\video.h264 -f yuv4mpegpipe -pix_fmt yuv420p -r 24000/1001 - 2>;NUL | ^
 "C:\Program Files\VFX\x265cli-mb\x265.exe" - --y4m -D 10 --fps 24000/1001 -p veryslow --pmode ^
 --pme --open-gop --ref 6 --bframes 16 --b-pyramid --bitrate 2500 --rect --amp --aq-mode 3 ^
 --no-sao --qcomp 0.75 --no-strong-intra-smoothing --psy-rd 1.6 --psy-rdoq 5.0 --rdoq-level 1 ^
 --tu-inter-depth 4 --tu-intra-depth 4 --ctu 32 --max-tu-size 16 --pass 2 --stats %I\v.stats --sar ^
 1 --range full -o %I\pass2.h265 & colorecho "Pass 2 done for Episode %I/"!EPNUM!" of "!SERIES!"" ^
 10) & echo !SERIES! transcoding complete | blat - -t "myself@another.mailhost.com" -c ^
 "myself@mailhost.com" -s "x265 notification from !MACHINE!" & SET MACHINE= & SET EPNUM= & SET ^


expand/collapse source code
(export MACHINE=BEAST EPNUM=13 SERIES='AnimeX'; for i in {01..13}; do avconv -r 24000/1001 -i \
$i/video.h264 -f yuv4mpegpipe -pix_fmt yuv420p -r 24000/1001 - 2>/dev/null | nice -19 x265 - --y4m \
-D 10 --fps 24000/1001 -p veryslow --open-gop --ref 6 --bframes 16 --b-pyramid --bitrate 2500 \
--rect --amp --aq-mode 3 --no-sao --qcomp 0.75 --no-strong-intra-smoothing --psy-rd 1.6 --psy-rdoq \
5.0 --rdoq-level 1 --tu-inter-depth 4 --tu-intra-depth 4 --ctu 32 --max-tu-size 16 --pass 1 \
--slow-firstpass --stats $i/v.stats --sar 1 --range full -o $i/pass1.h265 && echo && echo -e \
"\e[1;31m`date +%H:%M`, pass 1 done for episode $i/$EPNUM of $SERIES\e[0m" && echo && avconv -r \
24000/1001 -i $i/video.h264 -f yuv4mpegpipe -pix_fmt yuv420p -r 24000/1001 - 2>/dev/null | nice \
-19 x265 - --y4m -D 10 --fps 24000/1001 -p veryslow --open-gop --ref 6 --bframes 16 --b-pyramid \
--bitrate 2500 --rect --amp --aq-mode 3 --no-sao --qcomp 0.75 --no-strong-intra-smoothing --psy-rd \
1.6 --psy-rdoq 5.0 --rdoq-level 1 --tu-inter-depth 4 --tu-intra-depth 4 --ctu 32 --max-tu-size 16 \
--pass 2 --stats $i/v.stats --sar 1 --range full -o $i/pass2.h265 && echo && echo -e \
"\e[1;31m`date +%H:%M`, pass 2 done for episode $i/$EPNUM of $SERIES\e[0m" && echo; done && echo \
"$SERIES transcoding complete" | mailx -s "x265 notification from $MACHINE" -r \
"myself@mailhost.com" -c "myself@another.mailhost.com" -S smtp-auth="login" -S \
smtp="smtp.mailhost.com" -S smtp-auth-user="myuser" -S smtp-auth-password="mysecurepassword" \

And that’s it. The loops for audio transcoding are simpler, as that part is so fast, it doesn’t need email notifications. Runs for minutes rather than days. When all is done, I’d usually fire up the MKVToolnix GUI, and prepare a mux for the first episode. There is a nice “copy command line to clipboard” function there when you click on “Muxing” after everything is set up. With that I can build another loop that muxes everything to final .mkv files. On Windows that part is more complicated if you want Unicode support, so I needed to create input files by using a generator I wrote in Perl for that, but that’s for another day… :)

Oh, and if you wanna ssh into your Linux or UNIX boxes from afar to check on your transcoders, consider launching them on a GNU screen] session. It’s immensely useful! Too bad it won’t work on the Windows cmd. :(

Sep 232014

CD burning logo[1] At work I usually have to burn a ton of heavily modified Knoppix CDs for our lectures every year or so. The Knoppix distribution itself is being built by me and a colleague to get a highly secure read-only, server-controlled environment for exams and lectures. Now, usually I’m burning on both a Windows box with Ahead [Nero], and on Linux with the KDE tool [K3B] (despite being a Gnome 2 user), both GUI tools. My Windows box had 2 burners, my Linux box one. To speed things up and increase disc quality at the same time the idea was to plug more burners into the machines and burn each individual disc slower, but parallelized.

I was shocked to learn that K3B can actually not burn to multiple burners at once! I thought I was just being blind, stumbling through the GUI like an idiot, but it’s actually really not there. Nero on the other hand managed to do this for what I believe is already the better part of a decade!

True disc burning stations are just too expensive, like 500€ for the smaller ones instead of the 80-120€ I had to spend on a bunch of drives, so what now? Was I building this for nothing?

Poor mans disc station

Poor mans disc station. Also a shitty photograph, my apologies for that, but I had no real camera available at work.

Well, where there is a shell, there’s a way, right? Being the lazy ass that I am, I was always reluctant to actually use the backend tools of K3B on the command line myself. CD/DVD burning was something I had just always done on a GUI. But now was the time to script that stuff myself, and for simplicities sake I just used the bash. In addition to the shell, the following core tools were used:

  • cut
  • grep
  • mount
  • sudo (For a dismount operation, might require editing /etc/sudoers)

Also, the following additional tools were used (most Linux distributions should have them, conservative RedHat derivatives like CentOS can get the stuff from [EPEL]):

  • [eject(eject and retract drive trays)
  • [sdparm(read SATA device information)
  • sha512sum (produce and compare high-quality checksums)
  • wodim (burn optical discs)

I know there are already scripts for this purpose, but I just wanted to do this myself. Might not be perfect, or even good, but here we go. The work(-in-progress) is divided into three scripts. The first one is just a helper script generating a set of checksum files from a master source (image file or disc) that you want to burn to multiple discs later on, I call it create-checksumfiles.sh. We need one file for each burner device node later, because sha512sum needs that to verify freshly burned discs, so that’s why this exists:

expand/collapse source code
  1. #!/bin/bash
  3. wrongpath=1 # Path for the source/master image is set to invalid in the
  4.             # beginning.
  6. # Getting path to the master CD or image file from the user. This will be
  7. # used to generate the checksum for later use by multiburn.sh
  8. until [ $wrongpath -eq 0 ]
  9. do
  10.   echo -e "Please enter the file name of the master image or device"
  11.   echo -e "(if it's a physical disc) to create our checksum. Please"
  12.   echo -e 'provide a full path always!'
  13.   echo -e "e.g.: /home/myuser/isos/master.iso"
  14.   echo -e "or"
  15.   echo -e "/dev/sr0\n"
  16.   read -p "> " -e master
  18.   if [ -b $master -o -f $master ] && [ -n "$master" ]; then
  19.     wrongpath=0 # If device or file exists, all ok: Break this loop.
  20.   else
  21.     echo -e "\nI can find neither a file nor a device called $master.\n"
  22.   fi
  23. done
  25. echo -e "\nComputing SHA512 checksum (may take a few minutes)...\n"
  27. checksum=`sha512sum $master | cut -d' ' -f1` # Computing checksum.
  29. # Getting device node name prefix of the users' CD/DVD burners from the
  30. # user.
  31. echo -e "Now please enter the device node prefix of your disc burners."
  32. echo -e "e.g.: \"/dev/sr\" if you have burners called /dev/sr1, /dev/sr2,"
  33. echo -e "etc."
  34. read -p "> " -e devnode
  36. # Getting number of burners in the system from the user.
  37. echo -e "\nNow enter the total number of attached physical CD/DVD burners."
  38. read -p "> " -e burners
  40. ((burners--)) # Decrementing by 1. E.g. 5 burners means 0..4, not 1..5!
  42. echo -e "\nDone, creating the following files with the following contents"
  43. echo -e "for later use by the multiburner for disc verification:"
  45. # Creating the per-burner checksum files for later use by multiburn.sh.
  46. for ((i=0;i<=$burners;i++))
  47. do
  48.   echo -e " * sum$i.txt: $checksum $devnode$i"
  49.   echo "$checksum $devnode$i" > sum$i.txt
  50. done
  52. echo -e ""

As you can see it’s getting its information from the user interactively on the shell. It’s asking the user where the master medium to checksum is to be found, what the users burner / optical drive devices are called, and how many of them there are in the system. When done, it’ll generate a checksum file for each burner device, called e.g. sum0.txt, sum1.txt, … sum<n>.txt.

Now to burn and verify media in a parallel fashion, I’m using an old concept I have used before. There are two more scripts, one is the controller/launcher, which will then spawn an arbitrary amount of the second script, that I call a worker. First the controller script, here called multiburn.sh:

expand/collapse source code
  1. #!/bin/bash
  3. if [ $# -eq 0 ]; then
  4.   echo -e "\nPlease specify the number of rounds you want to use for burning."
  5.   echo -e "Each round produces a set of CDs determined by the number of"
  6.   echo -e "burners specified in $0."
  7.   echo -e "\ne.g.: ./multiburn.sh 3\n"
  8.   exit
  9. fi
  11. #@========================@
  12. #| User-configurable part:|
  13. #@========================@
  15. # Path that the image resides in.
  16. prefix="/home/knoppix/"
  18. # Image to burn to discs.
  19. image="knoppix-2014-09.iso"
  21. # Number of rounds are specified via command line parameter.
  22. copies=$1
  24. # Number of available /dev/sr* devices to be used, starting
  25. # with and including /dev/sr0 always.
  26. burners=3
  28. # Device node name used on your Linux system, like "/dev/sr" for burners
  29. # called /dev/sr0, /dev/sr1, etc.
  30. devnode="/dev/sr"
  32. # Number of blocks per complete disc. You NEED to specify this properly!
  33. # Failing to do so will break the script. You can read the block count 
  34. # from a burnt master disc by running e.g. 
  35. # ´sdparm --command=capacity /dev/sr*´ on it.
  36. blocks=340000
  38. # Burning speed in factors. For CDs, 1 = 150KiB/s, 48x = 7.2MiB/s, etc.
  39. speed=32
  41. #@===========================@
  42. #|NON user-configurable part:|
  43. #@===========================@
  45. # Checking whether all required tools are present first:
  46. # Checking for eject:
  47. if [ ! `which eject 2&gt;/dev/null` ]; then
  48.   echo -e "\e[0;33meject not found. $0 cannot operate without eject, you'll need to install"
  49.   echo -e "the tool before $0 can work. Terminating...\e[0m"
  50.   exit
  51. fi
  52. # Checking for sdparm:
  53. if [ ! `which sdparm 2&gt;/dev/null` ]; then
  54.   echo -e "\e[0;33msdparm not found. $0 cannot operate without sdparm, you'll need to install"
  55.   echo -e "the tool before $0 can work. Terminating...\e[0m"
  56.   exit
  57. fi
  58. # Checking for sha512sum:
  59. if [ ! `which sha512sum 2&gt;/dev/null` ]; then
  60.   echo -e "\e[0;33msha512sum not found. $0 cannot operate without sha512sum, you'll need to install"
  61.   echo -e "the tool before $0 can work. Terminating...\e[0m"
  62.   exit
  63. fi
  64. # Checking for sudo:
  65. if [ ! `which sudo 2&gt;/dev/null` ]; then
  66.   echo -e "\e[0;33msudo not found. $0 cannot operate without sudo, you'll need to install"
  67.   echo -e "the tool before $0 can work. Terminating...\e[0m"
  68.   exit
  69. fi
  70. # Checking for wodim:
  71. if [ ! `which wodim 2&gt;/dev/null` ]; then
  72.   echo -e "\e[0;33mwodim not found. $0 cannot operate without wodim, you'll need to install"
  73.   echo -e "the tool before $0 can work. Terminating...\e[0m\n"
  74.   exit
  75. fi
  77. ((burners--)) # Reducing number of burners by one as we also have a burner "0".
  79. # Initial burner ejection:
  80. echo -e "\nEjecting trays of all burners...\n"
  81. for ((g=0;g&lt;=$burners;g++))
  82. do
  83.   eject $devnode$g &amp;
  84. done
  85. wait
  87. # Ask user for confirmation to start the burning session.
  88. echo -e "Burner trays ejected, please insert the discs and"
  89. echo -e "press any key to start.\n"
  90. read -n1 -s # Wait for key press.
  92. # Retract trays on first round. Waiting for disc will be done in
  93. # the worker script afterwards.
  94. for ((l=0;l&lt;=$burners;l++))
  95. do
  96.   eject -t $devnode$l &amp;
  97. done
  99. for ((i=1;i&lt;=$copies;i++)) # Iterating through burning rounds.
  100. do
  101.   for ((h=0;h&lt;=$burners;h++)) # Iterating through all burners per round.
  102.   do
  103.     echo -e "Burning to $devnode$h, round $i."
  104.     # Burn image to burners in the background:
  105.     ./burn-and-check-worker.sh $h $prefix$image $blocks $i $speed $devnode &amp;
  106.   done
  107.   wait # Wait for background processes to terminate.
  108.   ((j=$i+1));
  109.   if [ $j -le $copies ]; then
  110.     # Ask user for confirmation to start next round:
  111.     echo -e "\nRemove discs and place new discs in the drives, then"
  112.     echo -e "press a key for the next round #$j."
  113.     read -n1 -s # Wait for key press.
  114.     for ((k=0;k&lt;=$burners;k++))
  115.     do
  116.       eject -t $devnode$k &amp;
  117.     done
  118.     wait
  119.   else
  120.     # Ask user for confirmation to terminate script after last round.
  121.     echo -e "\n$i rounds done, remove discs and press a key for termination."
  122.     echo -e "Trays will close automatically."
  123.     read -n1 -s # Wait for key press.
  124.     for ((k=0;k&lt;=$burners;k++))
  125.     do
  126.       eject -t $devnode$k &amp; # Pull remaining empty trays back in.
  127.     done
  128.     wait
  129.   fi
  130. done

This one will take one parameter on the command line which will define the number of “rounds”. Since I have to burn a lot of identical discs this makes my life easier. If you have 5 burners, and you ask the script to go for 5 rounds that would mean you get 5 × 5 = 25 discs, if all goes well. It also needs to know the size of the medium in blocks for a later phase. For now you have to specify that within the script. The documentation inside shows you how to get that number, basically by checking a physical master disc with sdparm –command=capacity.

Other things you need to specify are the path to the image, the image files’ name, the device node name prefix, and the burning speed in factor notation. Also, of course, the number of physical burners available in the system. When run, it’ll eject all trays, prompt the user to put in discs, and launch the burning & checksumming workers in parallel.

The controller script will wait for all background workers within a round to terminate, and only then prompt the user to remove and replace all discs with new blank media. If this is the last round already, it’ll prompt the user to remove the last media set, and will then retract all trays by itself at the press of any key. All tray ejection and retraction is done automatically, so with all your drive trays still empty and closed, you launch the script, it’ll eject all drive trays for you, and retract after a keypress signaling the script all trays have been loaded by the user etc.

Let’s take a look at the worker script, which is actually doing the burning & verifying, I call this burn-and-check-worker.sh:

expand/collapse source code
  1. #!/bin/bash
  3. burner=$1   # Burner number for this process.
  4. image=$2    # Image file to burn.
  5. blocks=$3   # Image size in blocks.
  6. round=$4    # Current round (purely to show the info to the user).
  7. speed=$5    # Burning speed.
  8. devnode=$6  # Device node prefix (devnode+burner = burner device).
  9. bwait=0     # Timeout variable for "blank media ready?" waiting loop.
  10. mwait=0     # Timeout variable for automount waiting loop.
  11. swait=0     # Timeout variable for "disc ready?" waiting loop.
  12. m=0         # Boolean indicating automount failure.
  14. echo -e "Now burning $image to $devnode$burner, round $round."
  16. # The following code will check whether the drive has a blank medium
  17. # loaded ready for writing. Otherwise, the burning might be started too
  18. # early when using drives with slow disc access.
  19. until [ "`sdparm --command=capacity $devnode$burner | grep blocks:\ 1`" ]
  20. do
  21.   ((bwait++))
  22.   if [ $bwait -gt 30 ]; then # Abort if blank disc cannot be detected for 30 seconds.
  23.     echo -e "\n\e[0;31mFAILURE, blank media did not become ready. Ejecting and aborting this thread..."
  24.     echo -e "(Was trying to burn to $devnode$burner in round $round,"
  25.     echo -e "failed to detect any blank medium in the drive.)\e[0m"
  26.     eject $devnode$burner
  27.     exit
  28.   fi
  29.   sleep 1 # Sleep 1 second before next check.
  30. done
  32. wodim -dao speed=$speed dev=$devnode$burner $image # Burning image.
  34. # Notify user if burning failed.
  35. if [[ $? != 0 ]]; then
  36.   echo -e "\n\e[0;31mFAILURE while burning $image to $devnode$burner, burning process ran into trouble."
  37.   echo -e "Ejecting and aborting this thread.\e[0m\n"
  38.   eject $devnode$burner
  39.   exit
  40. fi
  42. # The following code will eject and reload the disc to clear the device
  43. # status and then wait for the drive to become ready and its disc to
  44. # become readable (checking the discs block count as output by sdparm).
  45. eject $devnode$burner &amp;&amp; eject -t $devnode$burner
  46. until [ "`sdparm --command=capacity $devnode$burner | grep $blocks`" = "blocks: $blocks" ]
  47. do
  48.   ((swait++))
  49.   if [ $swait -gt 30 ]; then # Abort if disc cannot be redetected for 30 seconds.
  50.     echo -e "\n\e[0;31mFAILURE, device failed to become ready. Aborting this thread..."
  51.     echo -e "(Was trying to access $devnode$burner in round $round,"
  52.     echo -e "failed to re-read medium for 30 seconds after retraction.)\e[0m\n."
  53.     exit
  54.   fi
  55.   sleep 1 # Sleep 1 second before next check to avoid unnecessary load.
  56. done
  58. # The next part is only necessary if your system auto-mounts optical media.
  59. # This is usually the case, but if your system doesn't do this, you need to
  60. # comment the next block out. This will otherwise wait for the disc to
  61. # become mounted. We need to dismount afterwards for proper checksumming.
  62. until [ -n "`mount | grep $devnode$burner`" ]
  63. do
  64.   ((mwait++))
  65.   if [ $mwait -gt 30 ]; then # Warn user that disc was not automounted.
  66.     echo -e "\n\e[0;33mWARNING, disc did not automount as expected."
  67.     echo -e "Attempting to carry on..."
  68.     echo -e "(Was waiting for disc on $devnode$burner to automount in"
  69.     echo -e "round $round for 30 seconds.)\e[0m\n."
  70.     m=1
  71.     break
  72.   fi
  73.   sleep 1 # Sleep 1 second before next check to avoid unnecessary load.
  74. done
  75. if [ ! $m = 1 ]; then # Only need to dismount if disc was automounted.
  76.   sleep 1 # Give the mounter a bit of time to lose the "busy" state.
  77.   sudo umount $devnode$burner # Dismount burner as root/superuser.
  78. fi
  80. # On to the checksumming.
  81. echo -e "Now comparing checksums for $devnode$burner, round $round."
  82. sha512sum -c sum$burner.txt # Comparing checksums.
  83. if [[ $? != 0 ]]; then # If checksumming produced errors, notify user. 
  84.   echo -e "\n\e[0;31mFAILURE while burning $image to $devnode$burner, checksum mismatch.\e[0m\n"
  85. fi
  87. eject $devnode$burner # Ejecting disc after completion.

So as you can probably see, this is not very polished, scripts aren’t using configuration files yet (would be a nice to have), and it’s still a bit chaotic when it comes to actual usability and smoothness. It does work quite well however, with the device/disc readiness checking as well as the anti-automount workaround having been the major challenges (now I know why K3B ejects the disc before starting its checksumming, it’s simply impossible to read from the disc after burning finishes).

When run, it looks like this (user names have been removed and paths altered for the screenshot):


“multiburner.sh” at work. I was lucky enough to hit a bad disc, so we can see the checksumming at work here. The disc actually became unreadable near its end. Verification is really important for reliable disc deployment.

When using a poor mans disc burning station like this, I would actually recommend putting stickers on the trays like I did. That way, you’ll immediately know which disc to throw into the garbage bin.

This could still use a lot of polishing, and it’s quite sad, that the “big” GUI tools can’t do parallel burning, but I think I can now make due. Oh, and I actually also tried Gnomes “brasero” burning tool, and that one is far too minimalistic and can also not burn to multiple devices at the same time. They may be other GUI fatsos that can do it, but I didn’t want to try and get any of those installed on my older CentOS 6 Linux, so I just did it the UNIX way, even if not very elegantly. ;)

Maybe this can help someone out there, even though I think there might be better scripts than mine to get it done, but still. Otherwise, it’s just documentation for myself again. :)

Edit: Updated the scripts to implement a proper blank media detection to avoid burning starting prematurely in rare cases. In addition to that, I added some code to detect burning errors (where the burning process itself would fail) and notify the user about it. Also applied some cosmetic changes.

Edit 2: Added tool detection to multiburn.sh, and removed redundant color codes in warning & error messages in burn-and-check-worker.sh.

[1] Article logo based on the works of Lorian and Marcin Sochacki, “DVD.png” licensed under the CC BY-SA 3.0.

Mar 202012

config.mak with ldflagsJust recently a colleague of mine asked me to analyze a bunch of “secure” log files to extract the logins of key-based OpenSSHD login sessions of certain users. Actually these are users which are accessing our Subversion server through SSH tunnels from the Eclipse IDE. To see how intensively certain users are working with the system I was asked to create an output showing login sessions grouped by user and then sorted by month, then day. Since our “secure” logs date back 1 month it’s possible to collect enough data to get an idea of the general usage for each person accessing the system. To do this, a simple bash script and a few classic Unix tools can be used as shown:

users=(user1 user2 user3)
months=(Feb Mar Apr May Jun)
for i in "${users[@]}"
do {
  echo "Stats for user $i:";
  for j in "${months[@]}"
  do {
    cat /var/log/secure* | grep -e "Accepted publickey" -e $i -e $j | awk '{printf "logins on " $1 " "; printf $2 " by "; print $9}' | uniq -c | sort -n -k5
  }; done;
}; done;

So you need to add users that you want to look for to the “users” array on top of the script. Just add as many as you need. The script greps for “Accepted publickey”, so it collects successful key-based login attempts. You can of course easily change this to look for failed logins (detecting break-in attempts) or other lines as well. Equally you may change what you want to group it by, just change the fields of the “users” array to do that. When running the script, output might look somewhat like this (users without any logins are still shown, but with no login lines):

Stats for user user1:
      3 logins on Feb 27 by user1
      2 logins on Feb 29 by user1
     10 logins on Mar 1 by user1
      1 logins on Mar 2 by user1
      1 logins on Mar 6 by user1
      1 logins on Mar 8 by user1
      2 logins on Mar 13 by user1
Stats for user user2:
Stats for user user3:
      3 logins on Mar 4 by user3
      2 logins on Mar 5 by user3
      1 logins on Mar 11 by user3
      4 logins on Mar 12 by user3
      3 logins on Mar 17 by user3
      7 logins on Feb 27 by user3

That’s it. It’s not the most efficient way to do this, because the entire bunch of log files gets read again and again for each “user times months”, but that’s the trade off for the obvious simplicity of the code. Reading the log files only once and doing the analysis in one shot would require more complex code. But for a few megabytes worth of logs and around 10-20 users this should work reasonably fast. In my case as shown above, it does the processing for around 10 users and 5 months in less than 5 seconds.