Responsive video

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Last update : June 27, 2014

Responsive webdesign needs not only adaptive images, but also fluid videos. The pioneers in emdedding responsive videos in webpages are Chris Coyier and Dave Rupert. They created in 2011 FitVids, a lightweight, easy-to-use jQuery plugin for reactive width video embeds. FitVids automates the Intrinsic Ratio Method by Thierry Koblentz to achieve fluid width videos in your responsive web design. The source code is available at Github.

Here is a list of more useful links to contributions about responsive video :

Language localization with Poedit

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Language localization differs from translation, because it involves a comprehensive study of the target culture in order to correctly adapt the product to local needs. Poedit is a free, open source and cross-platform gettext catalog editor to aid in the process of language localization. Poedit provides compact view of data and very effective UI. Poedit is developed by Vaclav Slavik. The latest version is 1.5.5. released on February 4, 2013. The sources are available at Github.

MPEG-4 Tools

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Last update : September 16, 2013

To create and modify MPEG-4 Multimedia files, you need different MPEG-4 tools, e.g. an encoder, a multiplexer and a packager :

MPEG-4 Tools : Video encoder

x264  (Wikipedia) is a free software library (libx264) and application (x264.exe) for encoding video streams into the H.264/MPEG-4 AVC format, and is released under the terms of the GNU GPL. X264 provides best-in-class performance, compression, and features, gives the best quality and has the most advanced psychovisual optimizations. A comparison with other H264 codecs is available at the MSU Graphics & Media Lab (Video Group) of Lomonosov Moscow State University. The leader in this comparison for software encoders is x264, followed by MainConcept, DivX H.264 and Elecard.

X264.exe is a command line tool. A typical command to enter in the Command Prompt Window looks as follows :

x264.exe --crf 18 --ref 3 --bframes 2 --subme 3 --keyint 100 --sar 1:1 --output %1.mkv %1
pause

All available parameters can be listed with the command x264 –fullhelp. The purpose and use of all x264 settings is also explained on the MeWiki website.

The fourcc code of the X264 codec is X264.

MPEG-4 Tools : Multiplexer

To encode videos, x264 is not sufficient. Audio, subtitles and metadata should be added, and all these data need to be multiplexed. Therefore other tools are needed. FFmpeg is one of these tools. FFmpeg is a free software project that produces libraries and programs for handling multimedia data. It includes libavcodec, the leading audio/video codec library and libavformat, an audio/video container mux and demux library. FFmpeg is published under the GNU Lesser General Public License 2.1+ or GNU General Public License 2+, depending on which options are enabled. The ffmpeg component is a command-line tool to convert one video file format to another. X264 is added as an external library to FFmpeg. Zeranoe has great static builds of FFmpeg for Windows with libx264 included. Other useful external libraries are the Fraunhofer AAC library for AAC encoding and the LAME library for MP3 encoding.

A very comprehensive documentation about ffmpeg , the libraries, utilities and tools is available at the FFmpeg website.

MPEG-4 Tools : Packager

A third command-line tool performing some manipulations on ISO media files like mp4 is MP4Box, the multimedia packager from GPAC (Project on Advanced Content). Dynamic Adaptive Streaming over HTTP (DASH) is one example. GPAC officially started as an open-source project in 2003 with the initial goal to develop from scratch, in ANSI C, clean software compliant to the MPEG-4 Systems standard, a small and flexible alternative to the MPEG-4 reference software. The GPAC framework is being developed at École nationale supérieure des télécommunications (ENST) as part of research work on digital media. A general documentation about MP4Box is available at the GPAC website.

MP4Box is a command-line tool, the following GUI’s are available :

  • MeGUI, by several authors (version 2356, released on June 8, 2013)
  • My MP4Box GUI, by Matthew Bodin (version 0.6.0.6, released on January 4, 2013)
  • Java MP4Box Gui, by Rune André Liland (version 1.7, released on May 18, 2013)
  • Yamb, by kurtnoise version 2.1.0.0 beta 2, released on June 29, 2009)

The following list provides links to additional posts about MPEG-4 tools :

ISMA, MPEGIF, OIPF, HbbTV, Xiph

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The Internet Streaming Media Alliance (ISMA) was Founded in December 2000 as a non-profit corporation by Apple Computer, Cisco Systems, Kasenna, Philips, and Sun Microsystems.

In 2010 ISMA was merged with the MPEG Industry Forum (MPEGIF).

The mission of ISMA was to accelerate the market adoption of open standards for streaming and progressive download of rich media over all types of Internet Protocols (IP). ISMA has released several specifications for the transport of rich media over IP, the main ones are :

  • ISMA 1.0 – details how to stream MPEG-4 Part 2 video (Simple Profile and Advanced Simple Profile) over IP networks.
  • ISMA 2.0 – details how to stream H.264/MPEG-4 AVC video and HE-AAC audio over IP networks.
  • ISMACryp – specifies an end-to-end encryption system for ISMA 1.0 and 2.0 streams.

The MPEG Industry Forum (MPEGIF), founded in 2000, was a non-profit consortium dedicated to further the adoption of MPEG Standards, by establishing them as well accepted and widely used standards among creators of content, developers, manufacturers, providers of services, and end users.

The group was involved in many tasks, including promotion of MPEG standards (MPEG-4, MPEG-4 AVC / H.264, MPEG-7 and MPEG-21), developing MPEG certification for products, organising educational events and collaborating on development of new de facto MPEG standards.

In June 2012 the MPEG Industry Forum closed its operation and merged its remaining assets with that of the Open IPTV Forum.

The Open IPTV Forum (OIPF) was formed in march 2007 to enable and accelerate creation of a mass market for IPTV by defining and publishing free-of-charge, standards-based specifications for end-end IPTV services of the future. The founding members Samsung, Ericsson, Sony Corporation, France Telecom, Telecom Italia and Philips have since been joined by other leading industry stakeholders.

The OIPF specifications are available on the OIPF website which hosts also the ISMA technical specifications and the MPEGIF informations.

The OIPF collaborates with the Hybrid Broadcast Broadband TV or “HbbTV” consortium, a major new pan-European initiative aimed at harmonising the broadcast and broadband delivery of entertainment to the end consumer through connected TVs and set-top boxes.

The Xiph.Org Foundation (open source community) is a non-profit corporation dedicated to protecting the foundations of Internet multimedia from control by private interests. Xiph.Org hosts a collection of open source, multimedia-related projects. The goal is to put the foundation standards of Internet audio and video into the public domain, where all Internet standards belong.

Foo and Hello World

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The term foo is sometimes used as a placeholder name in computer programming or computer-related documentation. Other placeholders, also referred to as metasyntactic variables, are bar, baz, qux and foobar. The word foo originated as a nonsense word from the 1930s.

The term foo is very often used in programming examples, much like the Hello World program is commonly used as an introduction.

Time Machine : rolling ball clock

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Last update : May 18, 2013
A rolling ball clock is a clock which displays time by means of balls and rails. It was invented by Harley Mayenschein in the 1970s. He patented the design and founded Idle Tyme Corporation in 1978, which manufactured these clocks from solid hardwoods.The US Patent 4,077,198 was issued to Harley Mayenschein on March 7, 1978.

Figure of US Patent 4,077,198

Figure of US Patent 4,077,198

The clock works by using steel balls to indicate the exact time. There are 3 main rails which are numbered for hours and minutes. The bottom rail represents the hours. The middle and upper rails are used to represent the minutes. An electric motor scoops up a ball every minute. Every five minutes, the top rail will dump and deposit a ball on the second rail. Every hour, the upper and middle rails dump and one ball is transferred to the bottom rail to increment the hours.

Original Rolling Ball Clock

Original Rolling Ball Clock

Mayenschein sold a license on the patent to Arrow Handicraft Corporation. The clocks were sold in kits to be assembled in one hour.

First page of the assembly instruction of the Arrow Ball Clock kit

First page of the assembly instruction of the Arrow Ball Clock kit

Arrow Handicraft Corporation made different versions of the clock kit : classic, large, Deluxe, and a Domino kit. Mattel also made the ball clocks under License.

When Harley passed away in 1985 the family closed the business. Joe Mayenschein, Harley’s Son and primary clock maker, started the business again a few years ago. It is a limited production operation; about five clocks per week are made and shipped on a First Come, First Served basis. Three options to order a clock (four colors to choice : walnut, cherry, oak, black satin) are offered at prices between 253$ and 300$.

The current version of the Arrow Rolling Ball Clock comes from the company Can You Imagine and is now called Time Machine – Kinetic Display Clock. Assembly is no longer required. All you have to do is put the balls on the rails. The Time Machine now has a seconds wheel which lets you see exactly when a ball is about to get scooped up.

clock_gadget

Rolling Ball Clock Gadget

I received today a Time Machine as a Christmas gift and enjoy watching the 1:00 drop when all three rails dump their balls to the feed rail at the bottom.

Adam Bowman (aBowman), a web developer who lives in Hallowell, Maine, creates small gadgets that can be added to webpages or your desktop. One of these gadgets is a rolling ball clock.

Additional informations about rolling ball clocks and related topics are available at the following links :

Synology package files

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Non-experienced users of a Synology DiskStation (NAS) have the possibility to use the package management option to update their system with other programs and possibilities. A special kind of package baring the extension .spk is used to do this update.

An .spk file is nothing more then a tar file, containing a standard structure and files. Every package will contain an INFO file, a compressed (gzip) tar file package.tgz and a directory scripts containing multiple shell scripts.

The file can be easily installed in the Synology DashBoard with the Package Center.

More informations about .spk packages are available at the following links :

Mobile data offloading with WiFi and Femtocells

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Mobile data offloading is the use of complementary network technologies for delivering data originally targeted for cellular networks. For mobile operators the main purpose for the offloading is to prevent congestion of the cellular networks.

The main complementary network technologies used for the mobile data offloading are WiFi and Femtocells. Wi-Fi offloading is an emerging business domain with multiple companies entering to the market with proprietary solutions. Depending on the services to be offloaded and the business model there may be a need for interworking between WiFi and mobile cellular networks. Three solutions have been analyzed so far :

  • Enhanced Generic Access Network (EGAN), a tight coupling architecture, specified by 3GPP (3rd Generation Partnership Project)
  • Interworking Wireless LAN (IWLAN), a loose coupling architecture, specified by 3GPP
  • Direct connection to the public Internet, the most straightforward way to offload data to the WiFi networks

There are three main initiation schemes of offloading procedures: WLAN scanning by ANDS (Access network discovery and selection function), user initiation or remotely-managed initiation.

Mobile data offloading for 3G/4G network using Femtocell technology is promoted by the industry Small Cell Forum.

DAS, SAN, RAID and NAS

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Last update : September 11, 2013

A Direct-attached storage (DAS) is a file-level computer data storage system directly attached to a server or workstation, without a storage network in between. The main protocols used for DAS connections are ATA, SATA, eSATA, SCSI, SAS, and Fibre Channel.

A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. A SAN does not provide file abstraction, only block-level operations.

A Redundant array of independent disks (RAID) is a storage technology that combines multiple disk drive components into a logical unit. Data is distributed across the drives in one of several ways called RAID levels, depending on what level of redundancy and what performance is required. In RAID 1, data is written identically to two drives, thereby producing a mirrored set.

A Network-attached storage (NAS) is a file-level computer data storage system connected to a computer network, providing data access to a heterogeneous group of clients. A NAS, in contrast to a SAN, uses file-based network sharing protocols such as NFS, SMB, CIFS or AFP. NAS systems are networked appliances which contain one or more hard drives, often arranged into logical, redundant storage containers or RAID arrays. The benefits of network-attached storage, compared to file servers, include faster data access, easier administration, and simple configuration.

The storage space can be comprised of USB or hard disk drives. A NAS can be sold with the drives included or without them. Like PCs, NAS units have memory and processors. With better processors and increased memory, you get better performance from a NAS, just as with PCs. Lunix is usually used as embedded operating system. Noise and security are two other important concerns.

In the last years, NAS devices have been gaining popularity in the home office (SOHO), because they are useful for more than just general centralized storage provided to client computers in environments with large amounts of data. Typical other usages are :

  • load balancing
  • email server
  • web server
  • media server
  • multimedia streaming
  • cloud-based backup
  • low-cost video surveillance
  • BitTorrent client

A list of NAS manufacturers is provided at Wikipedia. A list of links to additional informations about SAN’s is provided below :

The periodic table of chemical elements

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A chemical element is a pure chemical substance consisting of one type of atom, distinguished by its atomic number, which is the number of protons in its nucleus. Atoms are build of particles.

Isotopes are atoms of the same element (same number of protons), but having different numbers of neutrons. Most naturally occurring elements (66 of 94) have more than one stable isotope. For example, there are three main isotopes of carbon. All carbon atoms have 6 protons in the nucleus, but they can have either 6, 7, or 8 neutrons. Since the mass numbers of these are 12, 13 and 14 respectively, the three isotopes of carbon are known as carbon-12 (12C), carbon-13 (13C), and carbon-14 (14C). Carbon in everyday life and in chemistry is a mixture of 12C, 13C, and a very small fraction of 14C atoms. Its presence in organic materials is the basis of the radiocarbon dating method to date archaeological, geological, and hydrogeological samples.

The tabular display of the chemical elements, organized on the basis of their atomic numbers, electron configurations, and recurring chemical properties is called the periodic table. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.

Periodic table of chemical elements (Wikipedia)

As of 2012, the periodic table contains 118 confirmed chemical elements.The latest, ununseptium, has been identified in 2010. Of these 118 elements, 114 have been officially recognized and named by the International Union of Pure and Applied Chemistry (IUPAC). A total of 98 are known to occur naturally on earth. 80 of them are stable, while the others are radioactive, decaying into lighter elements. A detailed list of the 118 known chemical elements is available at Wikipedia.

The lightest of the chemical elements are hydrogen and helium, both created by the Big Bang nucleosynthesis during the first 20 minutes of the universe. They are by far the most abundant chemical elements in the universe. However, iron is the most abundant element making up the earth, and oxygen is the most common element in the earth’s crust.

Although all known chemical matter is composed of chemical elements, chemical matter itself constitutes only about 15% of the matter in the universe. The remainder is dark matter, a mysterious substance which is not composed of chemical elements.

When two distinct elements are chemically combined, with the atoms held together by chemical bonds, the result is termed a chemical compound. Two thirds of the chemical elements occur on earth only as compounds. Just six elements – carbon, hydrogen, nitrogen, oxygen, calcium, and phosphorus – make up almost 99% of the composition of a human body.