Water Marking Videos

Water marking / converting video formats is quite simple in Drupal and following contributed modules helps to achieve the same

FFMPEG CONVERTER

FFMPEG WRAPPER

Before installing both these modules, make sure ffmpeg is downloaded and installed on your server, you can confirm ffmpeg installed on your server by referring configuration page of the above mentioned modules.

On the back ground the following unix command will execute for you to convert / water mark your video

ffmpeg -sameq -i video1.mp4 -vhook '/usr/lib/vhook/watermark.so -f water_mark_img.jpg' video2.mp4

Where,

video1 is Video to be water marked

water_mark_img.jpg is your image to be used as a water marking

video2 is your water marked video (output)

you dont need to worry on executing this command, its given just to have an idea of how it works, your Drupal modules will take care of all these if it is configured properly

Please make sure

• The dimension / canvas size of the video and water marking image
• Check the exact path of ffmpeg installed and where 'watermark.so' file seated

Thanks

Devaraj

How to send HTML mail using SMTP authentication on Drupal

We had a need to send HTML formatted mail from a Drupal 7 site. We did some quick research and found the Mail system and HTML mail modules. We enabled the modules and configured them and figured We were done.

My colleague came back to me and told me that now, not only was the mail not sending as HTML, it wasn't sending at all!

Some research brought us to Using HTML Mail together with SMTP Authentication Support -- excellent!

We followed the steps in the tutorial and after creating the HTML mail / SMTP auth class we received a PHP error stating that Drupal had failed to load the class.

When you use the Mail system module to create a new class, behind the scenes it actually creates a new PHP (.inc) file and stores it in your sites /mailsystem/filename.inc . Unfortunately the file directory for the site I'm working on is outside of the Drupal root, and not easily accessible to the class loader. Along with this, we use a git deployment workflow, and the files directory is not version controlled.

Solution

We first grabbed a copy of the auto-generated file from the server, and then deleted the copy on the server. Then we added that file to a custom module using the files[] directive in the module's .info file (this tells Drupal to load the class). Finally we had to remove the existing entry for the file from the registry table of the database, making sure to remove the correct file, and that I had the generating module "mailsystem" as a WHERE clause.

Now we have a mail system class that does HTML formatting and SMTP authenticated delivery working with the appropriate modules, and it's version controlled too.

Thanks

Devaraj

Senior Developer

Group FMG

Caching in Drupal 6

The Basics

Caches are used to improve the performance of your Drupal site. Rather than extracting the same data over and over again every time a page is loaded, caching stores frequently accessed and relatively static data

in a convenient place and format.

Caching has a drawback in that it can lead to "stale" data. This means that the website outputs old data or content from the cache even though newer stuff exists somewhere else. This problem can be particularly troublesome for developers who can get confused as to why changes they expect to see happen arent. Hopefully, by reading this document, you'll have a more pleasant and less confusing Drupal experience.

What gets cached, where it gets cached, and how There are two different ways Drupal stores cached data:

1) Using files

Drupal can consolidate all the css files your site delivers on each page load and place them into a fewer number of files. The resulting files are also compressed. This is important for Drupal sites where its not unusual to have a dozen or more stylesheets associated with each page, depending on how many modules are enabled. Having so many stylesheets will increase page load times because the browser has to make several round trips to the server to download all the stylesheet files. By using the css caching feature, you can consolidate these files into fewer larger files and decrease page load time significantly.

Just like style sheets, javascript files can also be consolidated. However, these files are not compressed.

How to turn on stylesheet and javascript file caching

======================================================

First, be sure you have your "Download method" is set to "Public" (set at admin/settings/file-system). You will not be able to use stylesheet and javascript caching when your "Download method" is set to "Private."

Next, in the navigation menu, select "Administer -> Site Configuration -> Performance" (admin/settings/performance) and scroll down to the "Bandwidth optimizations" fieldset and check off "Enabled" for both CSS files and Javascript files.

Note that turning on stylesheet and javascript caching can interfere with theme development and should only be enabled in a production environment.

2) In your database

The main location where Drupal stores cached data is in special tables in your database. Drupal core sets up seven tables for caching data. Other modules will add additional cache tables to the database as needed. The seven tables set up by core are:

cache

An "all purpose" table that can be shared by various modules. This table is designed for modules that need to store only a few rows of data. Drupal core uses this table to store the following data:

* Variable data. These are variables that are set with the variable_set() function and retrieved with the variable_get() function. When this cache goes stale, it is refereshed by data from the variable table. A call to the variable_set function will trigger a cache refresh.

* Theme registry data. This registry is a listing of all the themes that can be overridden by theme developers. The existance of the theme registry makes it easy to overide themes by allowing a user to simply

drop a tpl.php file in the theme's directory. When this cache goes stale, it's regenerated from the function definitions contained in module and theme files.

* Schema data. This data contains information about the table structure of the database. When this cache goes stale, its regenerated from ???. A visit to the admin/build/modules page will trigger a cache refresh.

cache_block

A table for storing content generated by your blocks. This saves Drupal from having to repeatedly query the database for unchanged block content. When this cache goes stale, it is refreshed by data from the boxes table where block content is stored. Any update to a blocks content will trigger a cache refresh for that block. The

entire cache is refreshed when a node, comment, user, or taxonomy term is added or updated. Module developers have the option of gaining more control over when a particular blocks cache is refreshed using cache

granularity settings for their blocks. Refer to the constants defined at the top of the block.module for further details.

The block cache can be turned on an off at "Administer -> Site Configuration -> Performance" (admin/settings/performance).

Note that block caching is inactive when modules defining content access restrictions are enabled. For example, if organic groups, content access, taxonomy access modules or other modules that restrict

access to certain kinds of content are turned on, block caching will be turned off.

cache_filter

A table for storing filtered pieces of content. This saves Drupal from having to run the same expensive regular expression operations on unchanged content that gets run through the input filters. When this

cache goes stale, it is refreshed by the data in the node_revisions table which contains node content. Cron jobs, updates to nodes, and updates to filter formats will trigger cache refreshes.

cache_form

A table for storing forms generated by the forms api. This saves Drupal from having to rebuild a unchanged forms. When this cache goes stale, it is refreshed by output from the form module.

cache_menu

A table for storing the menu items and menu item hierarchies. This saves Drupal from having to regenerate the data structures needed to define the menu items and their hiearchies each page load. When the data goes stale, the cache is refreshed from the data contained in the menu table.

cache_page

A table for storing pages for anonymous users. This saves Drupal from making dozens or even hundreds of expensive queries needed to generate a page. When the cache for a particular page goes stale, it gets refreshed by the html output for that page. This cache can be turned on an off under "Administer -> Site Configuration -> Performance" (admin/settings/performance).

cache_update

A table used to store information about installed modules and themes. This saves Drupal from having to perform two very expensive operations for listing the installed modules and themes and the status of these modules and releases compared to whats available for download on drupal.org. When this cache goes stale, it is refresed from the data in the system table.

Thanks

Devaraj

Senior Developer

Group FMG