Archive for category Computing

Fuppes Slackware 13.2 x86_64 with ffmpeg transcoding

Posted by admin in Computing on May 27, 2010

install ffmpeg

install lame, mad, faad libraries

download fuppes SVN 660
it will give an error about not finding libavformat, so you need to add /usr/local/lib/pkgconfig
$ PKG_CONFIG_PATH=/usr/local/lib64/pkgconfig:/usr/lib64/pkgconfig:/usr/local/lib/pkgconfig
$./configure –enable-mad –enable-faad –enable-lame –enable-transcoder-ffmpeg

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Hard Drive Prices

Posted by admin in Computing on April 10, 2010

The 3 cheapest hard drive prices for each capacity from newegg. 1.5 TB is still the sweet spot. The slope is much steeper too making 1.5 TB extra sweet. The $/TB went down about $15 from two months ago from ~$80 to ~$65.

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Putting Octave Plots in LaTeX

Posted by admin in Computing on April 3, 2010

I like vector based formats for my plots if the data is vector based. I input png and pdf to latex. I can output png, eps and pdf from Octave. The problem is that the pdf outptut has extra whitespace. To get around the whitespace, I can copy and paste into powerpoint and save as pdf with a specific page size or I can do the following.

Plot the figure with size on paper set

> fh = figure(‘papersize’,[6 4],’paperposition’,[0 0 6 4]);

Output as a colored encapsulated postscript

> print(‘-depsc2′,’figure.eps’)

Turn EPS to a PDF with proper size. You can edit the pdf later if need be.

$ ps2pdf -dEPSCrop figure.eps

Add figure to paper with proper size

\usepackage{graphicx}

\includegraphics[width=6in]{figure.pdf}

References

ps2pdf bounding box & page size problem – LinuxQuestions.org

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DSL Video Streaming

Posted by admin in Computing on February 19, 2010

The cheapest DSL from AT&T is limited to 768 kbps for downloading. They call it broadband, but with all the video content on the web now, I think people need more bandwidth. If I max out the DSL video streaming, then I can do 128 kbps audio and 640 kbps for video.

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Lossless video

Posted by admin in Computing on February 18, 2010

I like to use Big Buck Bunny, because it is completely free in terms of copyright and licensing. All the source files are provided, so you can generate an arbitrary resolution movie. Thankfully xiph.org has taken the time to render all the frames in 1080p in an uncompressed png format. The audio is also offered in 5.1 lossless flac format.

Here’s a test run for the first 15 seconds of the movie into a completely lossless ffv1 video codec and flac audio vodec avi.

$ ffmpeg -t 15 -r 24 -f image2 -i BBB/BBB-1080-png/big_buck_bunny_%05d.png \
-i BBB/BigBuckBunny-stereo.flac -vcodec ffv1 -s 1280x720 test.avi

The result however is difficult to play, because of the immense amount of data that needs to be read off of the hard drive. I need to try reading this off a RAID or a solid state drive.

video stats

  • frames: 14315
  • fps: 24
  • duration: 9:56.5 minutes
  • bytes for video (uncompressed): 89,050,752,000
  • bytes for frames (lossless compression): ~30,292,344,000
  • bytes per frame (uncompressed): 6,220,800
  • average bytes per frame (lossless compression): ~2,116,100
  • video bitrate (uncompressed): 1,194,393,600
  • video bitrate (lossless compression): ~406,296,196

audio stats

  • 48000 Hz
  • 24 bit
  • bytes for stereo audio (uncompressed): 229,040,000
  • bytes for stereo audio (lossless compression): ~150,000,000
  • audio bitrate per channel: 1,536,000
  • audio bitrate per channel(lossless compression): ~1,005,900
Uncompressed Lossless compression Lossy compression
Video (mbps) 1,194.4 406.3 10
Audio (kbps) 1536.0 1005.9 192

It’s a factor of 3 to go from uncompressed video to lossless, then another factor 0f 40 for lossy.

It’s a factor of 1.5 to go from uncompressed audio to lossless, then another factor of 5 for lossy.

Video might have compressed more since this is a computer generated animation. 90 gigs uncompressed to 30.5 gigs lossless to 800 megs lossy. lossy compression is very important if you want filesizes to be manageable. I have to applaud the creators of these various codecs for being so effective. If I actually tried to encode the video with a lossless codec (ffv1), I would probably get more than a factor of 3 compression.

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NFTS Write Support in 2.6 Kernel

Posted by bumscientist in Computing on February 17, 2010

Enable NTFS write support under File Systems —> DOS/FAT/NT Filesystems —> NTFS file system support

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Python Script for Downloading

Posted by admin in Computing on February 17, 2010

Handy script to pull from a website

import sys
import os
# download files
for i in range(1,10):
  sUrl = "http://media.xiph.org/BBB/BBB-1080-png/";
  sFilename = "big_buck_bunny_" + str(i).zfill(5) + '.png';
  os.system('wget ' + sUrl + sFilename);

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Windows Programs

Posted by admin in Computing on February 16, 2010

Programs to install in windows
  • Avira AntiVir
  • Firefox w/ ABP and NoScript
  • Thunderbird
  • Sunbird
  • VLC
  • SecureCRT
  • SecureFX
  • TightVNC
  • Xming (mesagl version)
  • Pidgin
  • Quicktime
  • iTunes
  • Audacity
  • MikTeX
  • TexNicCenter
  • JabRef
  • Blender3d
  • 7zip
  • MS Office
  • Adobe CS

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Captchas

Posted by bumscientist in Computing on February 11, 2010

I added some captchas to decrease spamming. Even though my spam filter sorts spam out, it is getting harder and harder to tell false positives until I look at the website links added. Only humans are allowed to comment.

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SSH Tunneling VNC

Posted by bumscientist in Computing on February 7, 2010

Because I forgot, I decided to make a post.

on remote machine, start vncserver

$ vncserver

on local machine, tunnel ssh

$ ssh –L 5901:localhost:5901 user@host.com

$ vncviewer locahlost:5901

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