calculate the disk space based on file date

Contributed by PB:

du -h (current usage)

du -ch `find /path/to/files/ -mtime -365` (last one year)

du -ch `find /path/to/files/ -mtime -730` (last two years)


etc.

viewing our live streams on Android

There was a request from the team preparing a customized android tablet for radiosai to consider changing our embedded player to something based on html5 so that Android would play it. They suggested videojs.

But according to this stackoverflow post, it looks like videojs does not work with our Wowza server: a test page I made also did not work. Our jwplayer embed does have a html5 option, but that seems to work only on iOS devices - "Cupertino streaming".

Wowza forums recommend using RTSP for streaming to Android, and when I made a link like they suggested, that worked fine on my HTC Wildfire for recorded streams. So, perhaps the rtsp urls
rtsp://[our-server-ip-address]:1935/live/myStream
(where myStream is the stream name)
or
rtsp://[our-server-ip-address]:1935/vod/flv:our-filename.flv
is the way to go for Android.

using WinDirStat for disk cleanup

Earlier, I had FolderSize installed on my system, but it was sometimes troublesome in taking up system resources when I did not need it to be running and so on. So, uninstalled it, and now installed WinDirStat. Since it is a standalone application, I can run it only when I need to see the sizes of folders. Collects statistics reasonably fast, all local drives scanned in the time it took to write this post.

problem with HDMI output

Unfortunately, the cable which V gave me to test was probably not meant for HDMI -> VGA. I think it is meant for VGA -> HDMI. I connected my player to my projector with that cable, did not work, and when I put back my old cable which used to work, still not working. Had to run shows from laptop VGA out for a couple of days.

Borrowed a Mac mini from studio to test HDMI projector input, found it working. The Mac mini can play the video at 720p on the HDMI out without any glitches, but with 1080p, the video drops frames, runs at around 15 fps or so. Then, tried the bluray player once again, found it working now! Probably the issue was a loose cable.

ubuntu panel disappearing

V tried to install the Nvidia accelerated driver on the Toshiba AC100 Smartbook running Ubuntu 12.04, and his desktop panel disappeared, though clicking in the relevant place still opened the correct apps. He did not want to change to 12.10 since he preferred the Unity interface to the Lubuntu interface on 12.10.

Problem and solution seems to be described here.
http://askubuntu.com/questions/162854/launcher-icons-invisible-still-work-in-12-04

But it gets stuck as given below,
http://askubuntu.com/questions/146456/cant-restore-unity-desktop

So I just re-flashed and re-installed 12.04.

migration of codeigniter-based site to godaddy

Successfully migrated a site based on the codeigniter framework from a generic server with CPanel to Godaddy. Went smoother than expected, though both servers were Linux servers.

While exporting database, the information_schema database is actually not supposed to be exported or imported. One has to choose the other database and then export. On godaddy, the database has to be created first, and godaddy's control panel fixes that the superuser name (of the db) and the dbname have to be the same. After this was done, came across this "No input file specified" error. The answer, via stackoverflow, was in the github docs. Followed those steps of changing the config file (in two places - in the public folder as well as the admin folder) and changing the htaccess file, choosing to save it in Unix LF style using PsPad, and problem fixed.

Edit: The admin area was broken. To fix it, had to modify the htaccess file in the admin folder, change
RewriteRule ^(.*)$ /index.php?$1 [QSA,L]
to
RewriteRule ^(.*)$ /admin/index.php?$1 [QSA,L]

and also change the admin/config/config.php file, had to set the URI protocol to Auto in order for auth to work.
$config['uri_protocol']    = 'AUTO';

Microsoft WorldWide Telescope for fulldome

The Microsoft WorldWide Telescope has planetarium features - fulldome projection, warped view as well as fisheye, and the option to use custom warp files in Paul Bourke's format. Unfortunately the tours are bandwidth hungry, and render on the fly, so that many landscapes etc are seen blurry and partly downloaded when played. The "Render to video" feature for the Tours has an option to "wait for downloads to complete" but the feature seems buggy. When I try to render a dome master, it shows the files being written, but no files are seen in the chosen folder. When I try to render low res files, like 640x480, the files do render, but apparently the file write is not able to keep up with the video being played in realtime, so the app crashes instead of doing an async render. This test was done with version 3.0.76.1

This version also crashed on my WinXP machine when doing full screen in full dome fisheye format. But later, after a system restart, full-screen mode did not crash. But it does show visible "stitch boundaries" - quite spoils the night sky look!

Since my main interest in checking out MS WWT was to try and render fulldome masters, and it does not seem to be doing that for me, I'll uninstall it for now.

online resources for fulldome production

Tried out a few options of the many many resources available on the internet, like the ones mentioned in the Small Planetarium Yahoo Group.

1. Tried the dome-masters available at spacetelescope.org - unfortunately, only one of them is a bonafide animation - others seem to be just a single hubble image rotated around the centre of the dome. I can do simple rotations myself!
2. The Science on a Sphere program links to many hi-res movies - 2048x2048 on the public ftp site ftp://public.sos.noaa.gov - these movies are generally suitable only for projection on the sphere as designed, but some parts of some of the movies can perhaps be adapted for fulldome, like animations of LCROSS hitting the surface of the moon etc. In most cases, such animations may be available for fulldome from other sources, so it may not be worth the hassle to try this out. An interesting sidelight while downloading deserves a separate post.
3. Some youtube videos like the ones from jakimsuk are available in 720p and seem to be prewarped for 4x3 projection. But the material is probably copywrited, like Spitz trailers and so on.

downloading large files over ftp

When downloading files from ftp://public.sos.noaa.gov the connection was timing out, and the server did not seem to resume downloads correctly. So I tried downloading from our dedicated server, and then transferring from there to our machine using sftp. Worked like a charm. A 1.3 GB file downloaded in 6 minutes - 40 Mbps! Later, sftp transfer to our local machine took 3 hours or so.

1535001090 bytes received in 359.52 secs (4169.5 kB/s)

using stellarium screenshots in planetarium shows

Tried out various options on the dome -

1. taking screenshots from within stellarium using the Ctrl-S shortcut key or using scripting
2. saving screen-grabs as movies using Fraps and Taksi

The difference in quality is glaring. The best quality is seen with the screenshots captured from withing Stellarium without warping. That is, when the Spheric mirror distortion option is chosen, the quality degrades.

So, I will have to go with first creating screenshots in fisheye mode, then cropping them and distorting them.