Please, choose the right format to send me that text. Thanks.
April 13th 2010

I just received an e-mail with a very interesting text (recipies for pintxos), and it prompted some experiment. The issue is that the text was inside of a DOC file (of course!), which rises some questions and concerns on my side. The size of the file was 471 kB.

I thought that one could make the document more portable by exporting it to PDF (using OpenOffice.org). Doing so, the resulting file has a size of 364 kB (1.29 times smaller than the original DOC).

Furthermore, text formatting could be waived, by using a plain text format. A copy/paste of the contents of the DOC into a TXT file yielded a 186 kB file (2.53x smaller).

Once in the mood, we can go one step further, and compress the TXT file: with gzip we get a 51 kb file (9.24x), and with xz a 42 kB one (11.2x)

So far, so good. No surprise. The surprise came when, just for fun, I exported the DOC to ODT. I obtained a document equivalent to the original one, but with a 75 kB size! (6.28x smaller than the DOC).

So, for summarizing:

DOC

Pros

  • Editable.
  • Allows for text formatting.

Cons

  • Proprietary. In principle only MS Office can open it. OpenOffice.org can, but because of reverse engineering.
  • If opened with OpenOffice.org, or just a different version of MS Office, the reader can not be sure of seeing the same formatting the writer intended.
  • Size. 6 times bigger than ODT. Even bigger than PDF.
  • MS invented and owns it. You need more reasons?

PDF

Pros

  • Portability. You can open it in any OS (Windows, Linux, Mac, BSD...), on account of there being so many free PDF readers.
  • Smaller than the DOC.
  • Allows for text formatting, and the format the reader sees will be exactly the one the writer intended.

Cons

  • Not editable (I really don't see the point in editing PDFs. For me the PDF is a product of an underlying format (e.g. LaTeX), as what you see on your browser is the product of some HTML/PHP, or an exe is the product of some source code. But I digress.)
  • Could be smaller

TXT

Pros

  • Portability. You can't get much more portable than a plain text file. You can edit it anywhere, with your favorite text editor.
  • Size. You can't get much smaller than a plain text file (as it contains the mere text content), and you can compress it further with ease.

Cons

  • Formatting. If you need text formatting, or including pictures or content other than text, then plain text is not for you.

ODT

Pros

  • Portability. It can be edited with OpenOffice.org (and probably others), which is free software, and has versions for Windows, Linux, and Mac.
  • Editability. Every bit as editable as DOC.
  • Size. 6 times smaller files than DOC.
  • It's a free standard, not some proprietary rubbish.

Cons

  • None I can think of.

So please, if you send me some text, first consider if plain text will suffice. If not, and no edition is intended on my side, PDF is fine. If edition is important (or size, because it's smaller than PDF), the ODT is the way to go.

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Avoiding time_increment_bits problem when encoding bad header MPEG4 videos to Ogg Theora
January 28th 2010

There is some debate going on lately about the migration of YouTube to HTML5, and whether they (i.e. YouTube's owner, Google) should support H.264 or Theora as standard codecs for the upcoming <video> tag. See, for example, how the FSF asks for support for Theora.

The thing is, I discovered x264 not so long ago, and I thought it was a "free version" of H.264. I began using it to reencode the medium-to-low quality videos I keep (e.g., movies and series). The resulting quality/file size ratio stunned me. I could reencode most material downloaded from e.g. p2p sources to 2/3 of their size, keeping the copy indistinguishable from the original with the bare eye.

However, after realizing that x264 is just a free implementation of the proprietary H.264 codec, and in the wake of the H.264/Theora debate, I decided to give Ogg Theora a go. I expected a fair competitor to H.264, although still noticeably behind in quality/size ratio. And that I found. I for one do not care if I need a 10% larger file to attain the same quality, if it means using free formats, so I decided to adopt Theora for everyday reencoding.

After three paragraphs of introduction, let's get to the point. Which is that reencoding some files with ffmpeg2theora I would get the following error:

% ffmpeg2theora -i example_video.avi -o output.ogg
[avi @ 0x22b7560]Something went wrong during header parsing, I will ignore it and try to continue anyway.
[NULL @ 0x22b87f0]hmm, seems the headers are not complete, trying to guess time_increment_bits
[NULL @ 0x22b87f0]my guess is 15 bits ;)
[NULL @ 0x22b87f0]looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag
Input #0, avi, from 'example_video.avi':
  Metadata:
    Title           : example_video.avi
  Duration: 00:44:46.18, start: 0.000000, bitrate: 1093 kb/s
    Stream #0.0: Video: mpeg4, yuv420p, 624x464, 23.98 tbr, 23.98 tbn, 23.98 tbc
    Stream #0.1: Audio: mp3, 48000 Hz, 2 channels, s16, 32 kb/s
  .

[mpeg4 @ 0x22b87f0]hmm, seems the headers are not complete, trying to guess time_increment_bits
[mpeg4 @ 0x22b87f0]my guess is 16 bits ;)
[mpeg4 @ 0x22b87f0]hmm, seems the headers are not complete, trying to guess time_increment_bits
[mpeg4 @ 0x22b87f0]my guess is 16 bits ;)
[mpeg4 @ 0x22b87f0]looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag
    Last message repeated 1 times
[mpeg4 @ 0x22b87f0]warning: first frame is no keyframe

I searched the web for solutions, but to no avail. Usually pasting literal errors in Google yields good results, but in this case I only found developer forums where this bug was discussed. What I haven't found is simple instructions on how to avoid it in practice.

Well, here it goes my simple solution: pass it through MEncoder first. Where the following fails:

% ffmpeg2theora -i input.avi -o output.ogg

the following succeeds:

% mencoder input.avi -ovc copy -oac copy -o filtered.avi
% ffmpeg2theora -i filtered.avi -o output.ogg

I guess that what happens is basically that mencoder takes the "raw" video data in input.avi and makes a copy into filtered.avi (which ends up being exactly the same video), building sane headers in the process.

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Accessing Linux ext2/ext3 partitions from MS Windows
July 2nd 2009

Accessing both Windows FAT and NTFS file systems from Linux is quite easy, with tools like NTFS-3G. However (following with the MS tradition of making itself incompatible with everything else, to thwart competition), doing the opposite (accessing Linux file systems from Windows) is more complicated. One would have to guess why (and how!) closed and proprietary and technically inferior file systems can be read by free software tools, whereas proprietary software with such a big corporation behind is incapable (or unwilling) to interact with superior and free software file systems. Why should Windows users be deprived of the choice over JFS, XFS or ReiserFS, when they are free? MS techs are too dumb to implement them? Or too evil to give their users the choice? Or, maybe, too scared that if choice is possible, their users will dump NTFS? Neither explanation makes one feel much love for MS, does it?

This stupid inability of Windows to read any of the many formats Linux can use gives rise to problems for not only Windows users, but also Linux users. For example, when I format my external hard disks or pendrives, I end up wondering if I should reserve some space for a FAT partition, so I could put there data to share with hypothetical Windows users I could lend the disk to. And, seriously, I abhor wasting my hardware with such lousy file systems, when I could use Linux ones.

Anyway, there are some third-party tools to help us which such a task. I found at least two:

I have used the first one, but as some blogs point out (e.g. BloggUccio), ext2fsd is required if the inode size is bigger than 128 B (256 B in some modern Linux distros).

Getting Ext2IFS

It is a simple exe file you can download from fs-driver.org. Installing it consists on the typical windows next-next-finish click-dance. In principle the defaults are OK. It will ask you about activating "read-only" (which I declined. It's less safe, but I would like to be able to write too), and something about large file support (which I accepted, because it's only an issue with Linux kernels older than 2.2... Middle Age stuff).

Formatting the hard drive

In principle, Ext2IFS can read ext2/ext3 partitions with no problem. In practice, if the partition was created with an inode size of more than 128 bytes, Ext2IFS won't read it. To create a "compatible" partition, you can mkfs it with the -I flag, as follows:

# mkfs.ext3 -I 128 /dev/whatever

I found out about the 128 B inode thing from this forum thread [es].

Practical use

What I have done, and tested, is what follows: I format my external drives with almost all of it as ext3, as described, leaving a couple of gigabytes (you could cut down to a couple of megabytes if you really want to) for a FAT partition. Then copy the Ext2IFS_1_11a.exe executable to that partition.

Whenever you want to use that drive, Linux will see two partitions (the ext3 and the FAT one), the second one of which you can ignore. From Windows, you will see only a 2GB FAT partition. However, you will be able to open it, find the exe, double-click, and install Ext2IFS. After that, you can unplug the drive and plug it again...et voilĂ , you will see the ext3 partition just fine.

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Gmail and browser discrimination
June 4th 2008

Due to Iceweasel (Firefox) being so slow on my machine, I switched to Konqueror, which is reasonably fast and full of features, but nowhere as good as Iceweasel, I must say. However, IW is unbearable, so I'm waiting for FF 3.0 to use IW again.

I use an e-mail client to read my e-mail over IMAP, my main account being a Gmail one. However, I sometimes visit the Gmail site, for example to set it to fetch e-mail from some other accounts. I had always done it with IW, and everything worked fine, but now with Konqueror it doesn't.

With Konqueror I get the message:

and some features are missing (specifically, the option set how to fetch e-mail from other accounts, and some others).

I could understand it if Konqueror were missing some functionality/plugin that IW has and Gmail requires. But it is not the case. I can tell Konqueror to identify itself as Firefox, and THEN the Gmail page shows up correctly, so obviously it's not due to Konqueror's limitations. It sounds like a case of sloppy programming from the guys at Google, with something like:

if browser is one of 'IE', 'Firefox', 'Safari':
  show this page
else:
  show dumbed down page

After years of discrimination to non-IE users, and a tremendous fight to make webmasters produce standards-compliant sites, instead of specific browser-compliant ones, we still have to suffer this shit. And from Google, the "don't be evil" guys, supporters of free software and all that BS.

By the way, this issue is known, and mentioned, for example, in the Wikipedia page for Gmail.

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