Unfortunately I was too rushed to place attribution in the filenames, and so it is not obvious who took each photo.  Luckily we all used different camera models, and that information is still present in the exif metadata.  I used this to split the photos into directories and embed the photographer in both metadata and filename.

I was shooting on my Nikon D200, and so was able to separate my photos by:

for ii in *.jpg; do if grep -q "NIKON D200" $ii ; then mv $ii lachlan/ ; fi ; done

This says: for each jpg file, check if it contains “NIKON D200″ in the exif metadata and if it does then move it to the subdirectory lachlan/

All you need to do is find the camera model string to search for (my friends with Canons had things like “Canon EOS 30D”).  Now I’m going to append photographer names to the filenames, and then return them to their original chronological directories.

[For Facebook Notes readers: this post is redirected from my personal website lachlan.rogers.name]

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The Beamer class for LaTeX is a great way to produce very nice presentation slides with useful features such as automatic progress markers and internal hyperlinks. Being LaTeX, it is also possible to completely change the output formatting by simply altering certain document settings. This allows me to produce slides that have black backgrounds for better projection onto a screen, and then change a single line (specifying the colour theme) to get a white-background version optimised for printing on paper.

To make it even more efficient to print, I used the following command to fit 3 slides to an A4 page:

pdfnup --frame false --nup 1x3 --paper a4paper --orient auto --pages all --trim "0 0 0 0" --delta "1cm 1cm" --offset "0 0" --scale 0.91 --turn true --noautoscale false --openright false --column false --columnstrict false --tidy true --outfile main3up.pdf main.pdf

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Today I wanted to convert some video that I recorded on a Nikon Coolpix camera into a format that would play nicely on my Android phone. The resolution needed to be scaled down for the small screen, and I knew that h264 was the best video codec. After some searching online, and a bit of experimenting, I found that this worked wonderfully:

ffmpeg -i input.avi -aspect 3:2 -s 400x300 -vcodec libx264 -b 480k -r 30 -acodec libfaac -ac 1 -ab 32k -padtop 10 -padbottom 10 -padleft 40 -padright 40 -sameq -pass 1 output.mp4

This is a two-pass process, and so this command should be repeated a second time with the last option changed to “-pass 2″.

The “pad” options are to make the geometry work. The screen on the HTC Magic has a resolution of 480×320 pixels, which is a 3:2 aspect ratio. The video I was converting had an aspect ratio of 4:3, and so it conveniently scaled to 400×300. The paddings fill the video out to the full 480×320, ensuring that the aspect ratio is right during playback.

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The tool that I use to manipulate my images according to their exif metadata is exiv2, and I can quite simply copy metadata from raw files to their corresponding jpgs (matching filenames, and all in the one working directory) with:

exiv2 insert -l./ -S.nef *.jpg

After sorting through the jpgs and deleting all but those worth keeping, I wanted to automatically remove the raw files of those deleted images. Sure enough, this is easily done with some bash shell magic:

for file in *??.jpg; do mv raw/${file%%.jpg}.nef 2> /dev/null rawKeep/ ; done

This command says “for each jpg file you find here, move the matching nef file from the subdirectory raw/ to the subdirectory rawKeep/”. I can then delete any files left in the raw/ subdirectory, as they mustn’t have a matching jpg.

People often ask my why I persevere with the “command line” (more technically the “shell”). It seems that they assume tools with graphical interfaces are more powerful and faster. These two routine tasks demonstrate yet again that the shell really is the most efficient way to do many common jobs.

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The first step is to copy the DVD to the hard drive (I only have one DVD drive).
cat /dev/sr0 > dvd.iso
where /dev/sr0 is my DVD device.

Then, after changing to a blank DVD, simply
growisofs -dvd-compat -Z /dev/dvd=dvd.iso
and it worked.

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After checking my laptop and finding that the doubt was justified, I remembered with relief that before heading over to Europe I had copied all my photos onto DVDs and left them in my office at uni (just in case something our house burnt down or something). I went to sleep mostly certain that I my accidentally deleted files were safe on discs at uni.

As you probably suspect, I did not have a copy of the photos on DVD. My DVD backups only went to the end of 2007, and I had deleted files from the first 2 months of 2008.

It is not a tragedy, as the main photos of consequence were from ASA Convention and I do have the best of my photos on the official DVD. However, it provided me with significant incentive to learn about data recovery on ext3 formatted partitions. I’ve included some of my discoveries below.

The first thing that I came across was not encouraging; the official ext3 FAQ says that it is impossible to un-delete files. However, a number of people have defied this statement and I quickly found a tool called ext3grep.

I have my external hard disk divided into 2 partitions and so I was able to use the empty half as a playground to store any recovered files. This turned out to be very useful, because running the command ext3grep /dev/sdb1 --restore-all --after=1218027000 did not “only process entries deleted on or after” Wed Aug 6 22:50:00 EST 2008, but seemed to “recover” every file on the partition. It took all night.

Happily, the full directory structure of my deleted “2008″ folder was recovered. Unfortunately, not all of the jpeg files were found, but it was nice to have some of them back again.

Looking a little bit further I found an article on Linux.com about a tool called ext3undel, which apparently uses Foremost and PhotoRec to do the work.  This article also explained fairly clearly why data recovery on ext3 partitions is difficult. I also stumbled across a guide to using foremost, and so decided to skip straight to this command-line utility.

I installed Foremost and gave it a try, and the results seemed impressive.

52661: 388052408.jpg 1 MB 198682832896
Foremost version 1.5.3 by Jesse Kornblum, Kris Kendall, and Nick Mikus
Audit File

Foremost started at Fri Aug 8 18:23:52 2008
Invocation: foremost -t jpeg -i /dev/sdb1
Output directory: /mnt/tmp/output
Configuration file: /etc/foremost.conf
------------------------------------------------------------------
File: /dev/sdb1
Start: Fri Aug 8 18:23:52 2008
Length: 186 GB (200005876224 bytes)

Num Name (bs=512) Size File Offset Comment

0: 00690176.jpg 1 MB 353370112
1: 00692792.jpg 1 MB 354709504
2: 00695328.jpg 1 MB 356007936
.
.
.
52662: 388055280.jpg 1 MB 198684303360
52663: 388058248.jpg 1 MB 198685822976
52664: 388061320.jpg 536 KB 198687395840
Finish: Fri Aug 8 20:36:15 2008

52665 FILES EXTRACTED

jpg:= 52665
------------------------------------------------------------------

Foremost finished at Fri Aug 8 20:36:16 2008

I’ve left out a lot of lines in the middle, but you can see the important details: about 2 and a quarter hours with a total of 52665 jpg files extracted (a total of 23 GB)!  Sadly, almost all of these files were not complete recoveries of the images.  The data corruption and partial recovery, however, did give rise to some very intriguing artistic effects, and I’ve included some samples here.  I couldn’t help thinking it was rather analogous to accidental light-damage back in the film era of photography.

I also gave PhotoRec a go, and it can also be told to only look for jpg files. It found a lot of images, but most of them were merely thumbnails from what appeared to be web-caches hidden in my backed up directories.

So of the three I found ext3grep to give me the best results as far as un-deleting my jpg files, however it also took the longest and produced the most storage-consuming recovery output. Its a bit disappointing that I have not yet been able to recover all the images I foolishly deleted, but I’ve certainly learnt about the value of true backups – storing files in at least 2 different places.

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I found this DVD creation article on the Gentoo wiki, and the following command worked brilliantly for me:

growisofs -dvd-compat -Z /dev/sr0 -joliet-long -R -V "<volume_name>" dvd/

where /dev/sr0 is my device and dvd/ the directory containing the desired contents of the DVD.

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The extra power of the command line comes at the cost of learning its ways, which are not always obvious or self-explanatory. Today I found a very good guide to increasing bash productivity using vi editing commands, and leveraging the command line history to save time and effort. Both of these articles have very good downloadable cheat-sheets.

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Not long ago I first heard about OpenMoko and liked the concept. The Phase 1 phones (still in the development stage) were released in July and Dr Shayne Flint had his here in Canberra by early August.

There are some remarkable differences between the Neo1973 (shown on the left) and the Iphone (click on image to enlarge). The Neo1973 has a full vga display of 640×480 pixels, which is twice the Iphone’s 320×480. It also has an SD slot for expandable storage, which the Iphone does not. Although not in the Phase 1 development version, the user version of the Neo1973 will have a GPS built in (yet to come for the Iphone). The Iphone has an accelerometer which allows the screen to automatically switch between portrait and landscape modes depending on how it is being held. The user Neo1973 will have two accelerometers, allowing game action like the Wii.

But the best difference is that while opening up the Iphone voids the warranty, the Neo1973 comes with a screwdriver!

As Dr Flint discussed at the CLUG meeting last night, the fully free (as in freedom) phone is driving innovation into a frenzy. Imagine being able to call a taxi simply by browsing OpenStreetMap and clicking on the screen where you want to go. The phone’s GPS knows where you are, and sends the appropriate information to the taxi service. One-click call-a-cab!

Or what about having your phone automatically switch to silent mode when it knows you are in or near a library or lecture theatre. How about having it remotely disabled by you when you loose it? Even better – get it to tell you where it is!

Everything that you thought was Sci-Fi will be one step closer to reality when the Neo1973 lands OpenMoko in userland a few months from now. Are you ready?

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I use a nifty command-line utility called jhead to automatically assign filenames based on the exif metadata tag that contains the information about when the photo was taken:

jhead -n%Y%m%d__%H%M-%S *.jpg

Having recently purchased a Nikon D70 digital SLR, I am playing with Nikon’s raw file format. To automatically rename the .nef (Nikon Electronic Format) files I have found Exiv2 that can be used as follows.

exiv2 -r'%Y%m%d__%H%M-%S' rename *.nef

This utility can also be used for jpeg files, and may end up superseding jhead for me. To insert human-meaningful keywords into the filenames, I use the rename command:

rename __ _a_great_photo_ 20070731*

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