Wednesday, September 24, 2014

Commandline to change firewal rules in Windows 7/8

I was looking for a commandline based approach to add new rules on Windows Firewall and it was simple to do:

  • First check if there are already some rules set:
    netsh advfirewall firewall show rule name=**App**
  • Then you add a separate rule for allowing input traffic (as required)
    netsh advfirewall firewall add rule name=**App** dir=in action=allow profile=public program=**App_Location** enable=yes
  • And a separate rule for allowing output traffic (as required)
    netsh advfirewall firewall add rule name=**App** dir=out action=allow profile=public program=**App_Location** enable=yes
  • Finally if required, the rule can be deleted
    netsh advfirewall firewall delete rule name=**App**

Tuesday, September 9, 2014

Automotic logon in to company intranet zone using Firefox

In AD based domain in company intranet, IE is the default browser and it does login automatically in to the intranet sites (in .NET it was Windows Authentication).

To do the same in firefox, do a "about:config" and the look for "network.negotiate-auth.trusted-uris". Add you company domains in there where you want automatic login like "bt.com"

Mozilla documentation : https://developer.mozilla.org/en-US/docs/Integrated_Authentication

Wednesday, May 28, 2014

Video Encoding Bitrates

NameResolutionLink
(Mbps)
Bitrate
(Mbps)
Video
(kbps)
Audio
(kbps)
240p424x2401.00.6457664
360p640x3601.50.9689664
432p768x4321.81.15108864
480p848x4802.01.28121664
480p HQ848x4802.51.60153664
576p1024x5763.01.92185664
576p HQ1024x5763.52.24217664
720p1280x7204.02.56249664
720p HQ1280x7205.03.203072128
1080p1920x10808.05.124992128
1080p HQ1920x108012.07.687552128
1080p Superbit1920x1080N/A20.3220000320
and for older, non-widescreen content (with only 75% as many pixels)...

NameResolutionLink
(Mbps)
Bitrate
(Mbps)
Video
(kbps)
Audio
(kbps)
240p320x2401.00.6457664
360p480x3601.20.7770464
480p640x4801.50.9689664
480p HQ640x4802.01.28121664
576p768x5762.31.47140864
576p HQ768x5762.51.60153664
720p960x7203.01.92185664
720p HQ960x7204.02.562432128
1080p1440x10806.03.843712128
1080p HQ1440x10809.05.765632128
1080p Superbit1440x1080N/A20.3220000320

Source : http://www.lighterra.com/papers/videoencodingh264/

Sunday, April 6, 2014

REST Standards

Just wanted to save these 2 links which very well explains the naming standards for REST services:
  1. The short one - https://github.com/WhiteHouse/api-standards 
  2. The long one (Martin Fowler) - http://martinfowler.com/articles/richardsonMaturityModel.html

Thursday, October 3, 2013

Picasa: Renaming File Names to Picasa Captions

Some 5 years back, I wrote on this blog on how to set the caption of a image as it file name. In those days, I used to change the filename first and then set the caption for picasa. Now things have moved online and today I set the caption first is Google + (which did not exist then) and then downloaded the album to my local picasa and tried to rename the file. How to do it?

With some Windows commandline revision and use of Exiv2 I was able to achieve it. So here it goes.
  1. I assume that you have downloaded the picasa web album to a local folder using picasa.
  2. Open command window and type in :
    forfiles /C "cmd /c ..\exiv2 -g Exif.File name -g Iptc.Application2.Caption  -Pv @file" > files.txt
  3. This will create a file "files.txt which will look like :
    100.jpg             1. My caption
    where the 1st column is the File Name and the 2nd column is the given caption.
  4. Open the files.txt in Notepad++ and edit it. Replace the huge space between the filename and caption with some deliminator like ';'. The result should look like:
    100.jpg;1. My caption
  5. Now in the command window type in:
    for /f "tokens=1,2  delims=;" %i in (files.txt) do ren "%i" "%j.jpg"
    This will take the filename as the first token and caption as the 2nd token as we have used the deliminator ';' and then do a rename. Note that I have use %j.jpg" to give it the correct extension.
  6. And the job is done :)

Monday, February 25, 2013

Windows 7 : Windows event log error 4201

Today morning, I faced a new problem. When I tried to connect to my VPN, I got the following error:

"Could not start the Remote Access Connection Manager service on local computer. Error 1068. The dependency service or group failed to start."

That is simple. So I went to the Remote Access Connection Manager Service and found 2 dependencies : Telephony and SSL. Started both of them and tried to start the service again: Same Error !!

Hmm.. thats a problem. To know more details, I looked in to the Eventlog and now that too gave an error :

 The service has not started and when I tried to start the service I got the error :  Cannot start windows event log service on Windows 7. Error 4201.

Now that's a bigger problem. Something has gone real bad with my laptop. All the solutions pointed to deleting the "C:\Windows\System32\LogFiles\WMI\RtBackup" directory and to do so I need to go to Safe Mode. Now my company's laptop does not allow you to go to Safe Mode without a password. So what to do.


  1. Make a copy of the folder RtBackup - just to be safe.
  2. Take the ownership of the folder - From System to Yourself and reboot your computer
  3. Now that you are owner - you can delete the folder :)
  4. And yes post restart everything was back to normal.

Sunday, February 10, 2013

How to download videos in Opera

I have used Opera as my favorite browser for last 10 -12 years now (since its 6th version). I had always liked it for its tab support, being light weight and also being available in Linux (a browser with better fonts for those days). Internet Explorer was slow and Firefox in its earlier versions was good but got quickly gloated with extensions and addons. Chrome is way to heavy.

So the good and bad thing in Opera is that it does not have too many addons. Without them the browser was solid and light weight. Without them, its features were limited so was good for browsing but lacked some features readily available on others. One of the features was to download flash streaming videos. Firefox and Chrome, both have good extensions to support it. Opera did not have it readymade and and all its supposed extensions were links to some video donwloader site which I don't prefer So how to do it.

Yes there's a way. Opera is known for its excellent cache and I tried to use it. Lets take the example of dailymotion from which say I want to download a video. So here are the steps:
  1. First clear the cache (Setting :: Delete Private Data)  - It will help us clear the old data and knowing new URLs will be easy. Later you will almost remember them.
    Before I move ahead, let me explain how things are working for video sites. First say a site like www.dailymotion.com will use another site (CDN) to deliver it content. For dailymotion its dmcdn.net similarly for youtube its ytimg.com. Also now the whole video is not delivered as one big file to the client browser. Its broken in to fragments. So now if you pause a video, you can see the download stop after some time i.e. after the fragment ends. This was always the case with dailymotion. With youtube, the download did not stop earlier but now even they too have implemented it. Its more like dowload on demand. So when the player reaches the end of fragment one, it starts downloading the fragment two. So here we go.
  2. After the cache is cleared, type in "opera:cache" in your browser location bar. It should show the cache as empty.
  3. Open dailymotion.com and search for say "gangnam style"
  4. Don't open the video. In the "opera:cache" tab now you will see URL's being cached
  5. Now play the video and pause it after 10 seconds. Refresh the cache now. Select the 4 checkboxes for video and then click the Preview link next to dmcdn.net. It will open a new tab:
  6.  Play the video for another 30 seconds and refresh the Cached Video list for dmcdn.net. You will find more items getting listed there.
  7.  Now have a close look at the URLs. They look like:
    1. http://vid2.ak.dmcdn.net/sec(6f246bdc0f86287961fdadfc57ab38e2)/frag(1)/video/623/746/50647326_mp4_h264_aac.flv
    2. http://vid2.ak.dmcdn.net/sec(6f246bdc0f86287961fdadfc57ab38e2)/frag(6)/video/623/746/50647326_mp4_h264_aac.flv
    3. http://vid2.ak.dmcdn.net/sec(6f246bdc0f86287961fdadfc57ab38e2)/frag(4)/video/623/746/50647326_mp4_h264_aac.flv
  8.  From inspection, you can see that that the whole URL is same except for the frag(N) part.
  9.  So we now we have the URL of the whole video if we just remove the frag part. In the above case, it is : http://vid2.ak.dmcdn.net/sec(6f246bdc0f86287961fdadfc57ab38e2)/video/623/746/50647326_mp4_h264_aac.flv
  10. Open this link in a new tab and you can now save the video in you local disk.
Enjoy downloading videos. 

Hint: You can do the same in firefox using "about:cache" but with addons who will do all this :)