The mobiReady testing tool evaluates mobile-readiness using industry best practices & standards. The free report provides both a score (from 1 to 5) and in-depth analysis of pages to determine how well your site performs on a mobile device.
The WordPress Mobile Pack gets a high score with this test tool.
Trackbacks were originally developed by SixApart, creators of the MovableType blog package. It’s a notification method between websites working as follows :
Most trackbacks send to Person A only a small portion (a teaser called an “excerpt”) of what Person B had to say. One problem is that there is no actual verification performed on the incoming trackback, and indeed they can even be faked.
Pingbacks were designed to solve some of the problems of trackbacks. The official pingback documentation is available on the website www.hixie.ch.
The best way to think about pingbacks is as remote comments:
There are two significant differences between pingbacks and trackbacks : pingbacks and trackbacks use drastically different communication technologies (XML-RPC and HTTP POST, respectively) and pingbacks do not send any content.
A useful guide “Introduction to Blogging” with more details about trackbacks and pingbacks is published by WordPress.
last update : April 3, 2012
A native photo gallery feature and an image uploader was added to WordPress in version 2.5. The documentation for these features is poor. A useful guide is available at the website yourbloghelper. The official wordpress guide is available at the WordPress Codex pages, informations about the gallery shorcodes are also listed.
To add additional management tools and to customize the presentations, you need a WordPress plugin. There are several great plugins available, the most reknowned is NextGEN Gallery.
Alex Rabe started in March 2007 the development of the Nextgen Gallery Plugin for WordPress. Version 0.33 was released on April 23th, 2007. Thomas Boley, the creator of the WordPress Plugin mygallery, stated in mid-2007 that the Nextgen Gallery plugin was a copy of his own plugin with a few new features.
Version 0.8 of the Nextgen Gallery Plugin was released in January 2008. Version 0.92 worked fine with the new WordPress version 2.5. In june 2008, the number of downloads of the plugin reached the level of 200.000. The release 1.00 of the Nextgen Gallery Plugin was announced on December 11, 2008. One year later, version 1.7.2 was published.
Several developers joined Alex Rabe to progress with the enhancement of the plugin or to create useful addons. A much requested feature of the Nextgen Gallery Plugin was a search function. A tutorial how to add this feature was written by Colophon. A working gallery with the search function is available at the website of Aengus Moran. An addon to the plugin implementing a gallery search feature (admin side) has been created by Marco Piccardo. Alex Rabe published a script to search for images in the Nextgen galleries.
Today, NextGEN Gallery is a full integrated Image Gallery plugin for WordPress with dozens of options and features downloaded by more than 5 million users. The current version is 1.9.3.
An extended tutorial about wordpress galleries and the NextGEN Gallery plugin has been published by Len De Groot at the website of the Knight Digital Media Center (kdmc), UC Berkeley Graduate School of Journalism.
NextGEN Gallery uses templates to customize the layout of the photos in WordPress. A built in template is carousel [nddgallery id=2 template=carousel]. Other templates can be added in the folder /wp-content/themes/mytheme/nggallery/gallery-mytemplate.php. Seven different style-sheets can be chosen to display the albums and galleries.
NextGEN Gallery has a built in image browser. To prevent page loading at every click, AJAX pagination can be enabled, but this works only in combination with the thumbnail javascript effect generator Shutter.
A second default thumbnail javascripts is Thickbox (not maintained any longer). Thickbox displays images with a thick white border over a sheer gray background. Shutter displays images similar but without a border.
The javascripts for Lightbox and Highslide can be added manually, customized code links can be manually integrated for other thumbnail javascript effects.
An built-in slideshow with different transition/fade effects, based on JQuery Cycle, can be replaced by the flash based JW Image Rotator created by Jeroen Wijering.
To get the ID of the saved media, hover the mouse about the name of the media in the gallery and look at the displayed url.
Tutorials about css decorative galleries are available at the WebDesignerWall. More informations about NextGEN Gallery are available at the following links :
Last update : January 30, 2013
FOURCC is short for “four character code” – an identifier for a video codec, compression format, color or pixel format used in media files. Another way to write FOURCC is 4CC. To find out which FOURCC’s are used within a media file, you need to use an application specialized to open and inspect the media file. Gspot, MediaInfo and ACIcodec are some of the tools supporting FOURCC.
A list of a few hundred video-codecs is available at the FOURCC website, a list of RGB- and YUV-pixel formats is available at the same site.
For audio codecs it is not FOURCC’s that is used, but rather audio tags, or an audio identifier – that identifies one specific audio codec or one type of audio compression scheme. An audio tag is an integer decimal value, often specified as a HEX value.
A great website about video- and audio-codecs is MovieCodec Forums/Downloads.
Frameserving is a process by which video data is transferred from one program to another. No intermediate or temporary files are created. The program that opens the source file(s) and outputs the video data is called the frameserver. The program that receives the data could be any type of video application. The input looks like a relatively small, uncompressed video file. This feature of frameserving enables you to open certain types of files in an application that wouldn’t normally support them.
There are three programs that are commonly used as frameservers. Those programs are Avisynth, VirtualDub, and VFAPI.
Further informations about frameserving are available at the AviSynth wiki-website.
Last update : January 30, 2013
I set up a list with useful software tools to display extended informations about media files :
Last update : August 31, 2013
To edit a video, you need to cut & join numerous clips. This process is called smart editing and is particularly difficult if the video is encoded with H264.
H.264/MPEG-4 Part 10 or AVC (Advanced Video Coding) is is a block-oriented motion-compensation-based codec standard developed by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG).
H.264 is used in Blu-ray Discs, cable television services, real-time videoconferencing, mobile devices, … The standard defines 17 sets of capabilities, which are referred to as profiles, targeting specific classes of applications.
The highly compressed video file formats like MPEG-2 or MPEG-4 were exclusively designed for playback or distribution… not for editing. The term “compressing” is misleading, because these video file formats are made in a similar fashion and achieve their very high compression rates by throwing away information. They rely on a system of deleting data that is unnecessarily repeated in frame after frame of the videos. The data is replaced by a reference to an earlier or later frame.
In MPEG-2 streams there are three types of pictures :
The following picture (courtesy Wikipedia) shows the relations between I, P and B frames.
I, P and B frames
The I, P, and B pictures are arranged in groups of pictures (GOP) in a way so that the video file can be played back by a video device or software. There are generally two types of GOP’s : short GOP’s and long GOP’s. The sequence of the transmitted frames is not linear; P-frames are send before the related B-frames.
The following picture shows a typical sequence of a short GOP (I =blue, P = red, B = yellow). The term VOP (video object plane) is used in relation with the video codecs (IVOP, PVOB, BVOP).
Short GOP sequence
You easily understand that cutting or joining such video sequences without disturbing the sequence of frames or the synchronization with the sound can be very complex.
In the case of MPEG-4 streams it’s even more difficult.
The granularity of the establishment of prediction types in MPEG-4 is brought down to a lower level called the slice level of the representation. A slice is a spatially distinct region of a picture that is encoded separately from any other region in the same picture. In that standard, instead of I pictures, P pictures, and B pictures, there are I slices, P slices, and B slices. Motion estimation provides for the searching of sub-macro blocks of variable size, from 16×16 down to 4×4 blocks. Motion vectors allow up to quarter pixel accuracy for luminance, and up to 1/8th pixel for chrominance. MPEG-4 carries out intra-prediction for intra coded blocks before the transform, performed on either 4×4 or 16×16 blocks and allowing up to 9 directional modes for direction dependent prediction. Residual data transforms are executed on 4×4 blocks with modified integer discrete cosine transform (DCT) which avoids rounding errors. The employment of an adaptive in-loop filter increases subjective quality of video. The standard provides two alternative and more efficient processes of entropy coding. Context-adaptive variable length coding (CAVLC) utilizes multiple variable length codeword tables for transform coefficient encoding considering spatial neighborhood of the coded block. Context-adaptive binary arithmetic coding (CABAC) in addition provides highly efficient automatic adjustment for underlying probability model of encoded data. Long GOP’S are usual in MPEG-4.
Cutting and joining MPEG-4 videoclips without re-encoding (lossless) to keep a high quality and without creating visual or audial drops at the edges of the movies is very challenging. Only a few software tools are capable to do such a task which is called “smart editing“.
MPEG-4 editor tool Machete
QuickTime pro MPEG-4 player & editor
A very simple MPEG-4 editor is Machete from Machetesoft. It’s a try-before buy-program, the current version is 4.0 build 33 released on March 22, 2013. The software is available at regnow for 15,99 euros.
Cutting videoclips or inserting other videoclips with Machete is only possible at the location of key-frames (I-pictures). Unfortunately a typical MPEG-4 videoclip has only very few key-frames (every 5 to 10 seconds).
A wellknown MPEG-4 player and editor is the pro-version of QuickTime from Apple. The current version is 7.7.3, build 1680.64. The selected part of a videoclip can be trimmed with the menu “Edit > Trim to Selection”. The trimmed videoclip can be saved with the same parameters without re-compression with the menu “File > Export …; Exporter > MPEG-4 sequence ; options >video and audio format > pass through”. A videoclip can be copied to the clipboard and added to another movie with the same features. I expected a clean export to MPEG-4 without affecting the audio or video streams, but this is not the case.
AvsPmod Editor with AviSynth
A very powerful and versatile video post-production tool is AviSynth, created by Ben Rudiak-Gould. It’s not a software you may usually think of programs (.exe and GUI), but it’s a video processing engine that works in the background. AviSynth uses scripts which tell the program what to do and what video to produce.
A Wiki on the main website provides some documentation and user guides about AviSynth. A more comprehensive documentation is available at the website of AnimeMusicVideos.org, a community dedicated to the creation, discussion, and general enjoyment of fan-made anime music videos. The AviSynth tutorial is part of a very useful documentation “Technical Guides to All Things Audio and Video” available on the same website.
The AviSynth syntax to program video scripts is available at the official wiki-website.
A package (AMVapp v3.1) including a lot of accessories and complementary software tools, described in the technical guides, is available at the AimeMusicVideos website. One of the tools is a text editor specifically designed for making AviSynth, called AvsP. It has been written in Python by qwerpoi. The most recent version is 2.0.2 released on October 27th, 2007. An enhanced version called AvsPmod has been created by Zarxrax, the latest version is 2.5.1 released on June 25, 2013.
The AvsPmod editor shows not only the resolution, framerate, colorspace, frame number, time-code and aspect ratio of the videoclip in the bottom bar, but also the position and color of the videopixel defined by the mouse pointer. To play back the video in real-time, you need an external directshow media player (for example Windows Media Player) which is activated with the AvsPmod preview button (4th button from the left). The VLC-player doesn’t work because it’s not a directshow player.
VirtualDub
VirtualDub is a video capture/processing utility for 32-bit and 64-bit Windows platforms, written by Avery Lee and licensed under the GNU General Public License (GPL). The current stable version is v1.9.11. An unofficial VirtualDub support forum is available at the website. A modified version of VirtalDub called VirtualDubMod has been discontinued since 2005.
To play and edit MPEG-4 videos in VirtualDub, specific plugins and filters are required. The most straightforward solution is to combine VirtualDub with AviSynth and AvsPmod.
Avidemux 2.5
Avidemux2.5 is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types using a variety of codecs. The tool is available for Linux, BSD, Mac OS X and Microsoft Windows under the GNU GPL license. The current version is 2.6.5 released on August 29, 2013. A detailed up-to-date documentation is available on the wiki-website.
The tool shows for each frame the type of picture (I, P or B). To save a selection of a clip in the default copy mode without re-encoding, the marker A and B must be key-frames (I-pictures). An automatic search for key-frames and for black-frames (pictures without content, often inserted between movies and commercials) is provided. To join videoclips use the menu “File > Append”. The Smart-Copy feature doesn’t work for videos encoded with the H264 codec. For some other codecs you’re asked whether you want to use Smart-Copy or not if you cut your video, and the first frame of a segment is not an I-frame, and you try to save it .
Womble MPEG Video Wizard DVD 5.0
Womble MPEG Video Wizard DVD 5.0 is a commercial MPEG editor with DVD authoring and full MPEG-4 and AC-3 encoder support. The price for a single user personal license is $99. A free trial download is available. The features of this program are smart rendering, no re-encoding, fast HD MPEG editing with frame accuracy, automatic Ad detection and removal, movie conversion to iPod’s and PSP’s, intuitive User Interface (UI) and batch processing.
The current release is 5.0.1.108 from June 2013.
A tutorial “How to Edit Out Commercials? ” is available at the Womble website.
Another commercial video editing tool is SmartCutter from FameRing. The company states that SmartCutter is the world’s first H.264 AVCHD MPEG2 frame accurate cutter without re-encoding! The price is 40$, a free trial is available. Other tools as a video browser and a video framer or bundled versions are also offered. The current version is 1.8.1 released on August 28, 2013.
A tutorial how to edit H.264/AVCHD/MPEG2 videos without re-encoding is available oh the FameRing website. The name FAME stands for Frame Accurate Movie EngineeRing.
Smart Cutter from FameRing
The record function of the VLC media player can be used to do a simple cutting of video clips.
My favorite editing tools are now AVS Video Remaker and AVS Video Editor from AVS4YOU, a project of Online Media Technologies Ltd, an english IT high-tech company, founded in 2004 and specialized in developing innovative video and audio solutions for end-users and professional developers. AVS4YOU is a collection of software tools (currently there are 20 tools available) for which you can purchase either an unlimited access license or a one-year access license and use aLL of the tools with that license.
I did a lot of tests with other low-price commercial and shareware video-editors and I experienced serious problems with most of them when loading my MPEG-4/H264 test videos.
Today I installed the TerraTec Magix Movie on DVD (version 7.0.3.8) with different video devices.
TV Edit
TV Record
The program allows to
I did several tests to digitize videos from an VHS-recorder on my Media-PC with a Dual Core Intel Pentium R 3 GHz CPU running Windows 7. The recording parameters have been the following :
There are no visible differences between the different quality values ranging from 1 to 15. With high quality values I noticed however some CPU performance problems (sound noise, frame skips).
The TerraTec TV device H5 with composite interface provides a good sound quality and a reasonnable video quality with a visible jitter between frames.
The second available audio driver Ligne (TerraTec H5) provides no sound.
The TerraTec video device G3 with composite or Scart interface provides a reasonnable sound quality and a good video quality.
The sound levels are not displayed in a reliable manner on the screen. With the second available audio driver Ligne (TerraTec G3), the audio levels are always shown, but they are very high, and there is a lot of echo.
The inbuilt TV-Card SAA 7131 is shown in the driver window, but without providing an image or a sound.
In general the software is not very stable and provides a lot of crashes in Windows 7. The same is true for Windows XP. New versions of the Magix Movie on DVD Software are available in USA (version 8 ) and in Germany (version 9 ), but they don’t have an optimal support for the TerraTec devices.
Windows Desktop
The desktop is the main screen area that you see after you turn on your computer and log on to Windows.
The desktop includes the Taskbar and the Sidebar. The Taskbar sits at the bottom of the screen and shows which programs are running and to switch between them. It also contains the Start button.
There are many ways to customize the taskbar to suit your preferences. For example, you can make the taskbar larger, have Windows automatically hide it when you’re not using it, and add toolbars to it. To unlock the Taskbar, right-click on it to select the unlock option in the menu. To move the Taskbar, click an empty space on it and then hold down the mouse button as you drag the taskbar to one of the four edges of the desktop. When the taskbar is where you want it, release the mouse button.
The Taskbar includes a Quick Launch Toolbar at the left and a Notification Area at the right.
On the side of the screen, the Sidebar contains small programs called gadgets. To open Windows Sidebar, click the following items : Start button, All Programs, Accessories, Windows Sidebar.
More details are available at the Microsoft Website.
WTV is the default container format used to record television shows in Microsoft Windows 7 Media Center. It’s the successor of DVR-MS, the format used to record television shows in Microsoft Windows XP Media Center Edition.
WTV’s video encoder supports encoding to H.264 1-pass CBR Baseline profile up to 1.5 Mbit/s, 640x480pixels at 30 frame/s, and the audio encoder supports low complexity AAC stereo at 44.1 or 48 kHz sample rate and 96, 128, 160 or 192 kbit/s bit rate.
WTV files can be played with the Windows Media Player on windows 7. An integrated conversion tool in the Media Center allows to change the files to the DVR-MS format which can be played on the common video players like VLC and analyzed with the common tools like Infomedia.
A TunerFreeMCE for the Media Center is available from Milliesoft.
A converter from wtv/dvr-ms to mpeg – mpeg2 – avi – divx – mp4 – mpeg-2 is available from DVRsoft.