Older blog entries for ole (starting at number 61)

18 Jul 2002 (updated 18 Jul 2002 at 14:47 UTC) »
Valgrind and GNU Emacs lovers

This patch (applied on subversions.gnu.org 2002/07/12) lets you easily debug code line-by-line on x86-linux using Justin Seward's excellent Valgrind memory debugger inside GNU Emacs.

  1. If you run Emacs 21.2, apply the patch to /usr/share/emacs/21.2/lisp/progmodes/compile.el or an optional location.
  2. You probably want to byte-compile it (M-x byte-compile-file RET)
  3. Now M-x compile RET
  4. Either put
    • this after Compile command: in the mini-buffer:
      valgrind -v --leak-check=yes --show-reachable=yes myprog
    • or this inside the source file:

       * Local variables:
       *  compile-command: "make -k; valgrind -v --leak-check=yes --show-reachable=yes myprog"
       * End:
  5. Finally, step forward and back in source files from the *compilation* buffer (of Valgrind error messages), using
    M-n (compilation-next-error) RET and M-p (compilation-previous-error) RET.


I'm collecting information and samples of proprietary RAW formats from digital still photography devices. Their usage is increasing with the new multi-megapixel cameras.

Simply put, image files in RAW format contain raw data (Bayer array) directly from a CMOS sensor; pure, unprocessed and lossless, opposed to typical JPEGs, where lossy compression is used to reduce file size (and quality).

Unfortunately, there is no universally accepted RAW standard format, so each manufacturer format (even on model basis) differs.

Fortunately, three of the formats are now reverse-engineered.

Support for RAW formats in free software is desirable:

From RAW data, images can be individually customied, different versions of the same image can be created and compared. In addition, any noise in images taken at higher ISO (typically 800 and 1600) can be significantly reduced by saving in RAW format vs. JPEG.

As the CMOS data is stored in a lossless format, no data is thrown away, allthough obfuscated with proprietary compression algorithms. In the case of Canon's RAW formats, they use (until recently secret) proprietary compression algorithm, that reduces the file size greatly. Some RAW formats, like the ones by Nikon in their D1-series cameras, Kodak in their DCS cameras, and Canon in EOS-1D, are disguised as a TIFF, but the data is still proprietary.

Life is Good.

Lately I've been writing a server for serving RTP2 packets of MPEG-2 transport stream over UDP in a project at work, using librtp by dreier of gnome-o-phone fame.

30 Nov 2001 (updated 11 May 2002 at 21:03 UTC) »

U.S. citizens: Please sign the Petition Against Software Patents.

During the weekend I built new Debian packages of gphoto2 beta3, GnoCam and gtkam. You can get them from http://www.ping.uio.no/~oka/debian/ and in upstream Debian as soon as my maintainer application is approved.

Tommorrow is the day for my first exam in formal logic.

"Universal Plug and Play (UPnP)" is mentioned in the these minutes from I3A/IT10 about implementing Picture Transfer Protocol over IP.

UPnP is a Microsoft-backed standard that enables the automatic discovery of devices on any particular network. Drivers and other discovery protocol information are located on the sensor/device itself.

Intel is working on a UPnP implementation for Linux under the BSD license.

Late breakfast.

Annett went with her parents today. We met Karl-Erik at the train station.

Took the subway to Forskningsparken and read mail for a couple of hours.

Børre Gaup has written Sami locale for glibc as part of the Skolelinux project.

Very PC and very cool.

Arrived in Manchester yesterday.

Staying in Cambridge Hall at Manchester Metropolitan University and attending the UKUUG Linux 2001 Conference.

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