Video Conferences -

Communicating today is instantly with any part of the world at our fingertips thanks to the global Internet network and the use of Computers, Laptops, Tablets and Intelligent Cellular Phones, as well as free applications like Whatsapp, Skype, Viper, among other.

David Lewis and James Green, Authors who have written about memory improvement, say "the mind retains images much better than words, numbers or abstract concepts." Given the sophistication of the human vision system, the human being's predilection for images is surprising, not only a large part of the brain is dedicated to vision and visual analysis but also the ability to transport information.

With video conferencing, a critical meeting takes only a few minutes to organize. They also prevent errors and are always available. Thanks to them, the information is always fresh, accurate and on time.

Canceling an important meeting, advancing it or postponing it is very easy, eliminating in this way the problems that this could bring to cancel the purchase of tickets at the last minute, or to reserve previous flights, etc.

The substantial decrease recorded in video conferencing equipment, as well as the lower cost and availability of communication services, have made the videoconferencing industry the fastest growing in the teleconferencing market.

Currently, most innovative companies in the world use videoconferencing to:

  • Administration of clients in advertising agencies.
  • Board meetings
  • Crisis management
  • Customer service
  • Long distance education
  • Engineering Development
  • Meeting of executives
  • Financial studies
  • Coordination of projects between companies
  • Manufacturing control
  • Medical diagnoses
  • Coordination of mergers and acquisitions
  • Management of the administrative information system
  • Management and support of purchase / sales
  • Hiring / interviews
  • Supervision
  • Training / training
  • Shorten the development cycles of your products
  • Communicate with your suppliers and partners
  • Improve product quality
  • Interview candidates for a certain position in the company
  • Manage the union or consolidation of companies
  • Direct the company more effectively
  • Obtain immediate support in foreign products or services

The organization of ISO standards has established a working group, known as MPEG (Group of experts in moving image), to develop four standards for the codification of audiovisual signals for storage in digital media. The speeds for the three standards (MPEG1, MPEG2, MPEG3, MPEG4)

An ISO bit string is built in two layers, the outer layer is the system layer and the inner layer is called the compression layer. The system layer provides the functions necessary for the use of one or more strings of compressed bits in a system.

The video and audio parts of this specification define the compression coding layer for audio and video data. The coding of another type of data is not defined by the specification, but is supported by the system layer, allowing other types of data to be adhered to the compression of the system.

The system layer supports four basic functions: the synchronization of multiple compressed strings during playback, the interleaving of multiple compressed strings into a single string, the initialization of the buffer for initial playback, and the identification of the time.

The MPEG standard specifies the encoded representation of video for digital storage media and specifies the decoding process. The representation supports the normal speed of reproduction as well as the special function of random access, fast playback, normal backward playback, pause procedures and freezing of image.

This international standard is compatible with the 525 and 625 line television formats and provides ease of use with personal computer monitors and workstations. This international standard is applicable primarily to digital storage media that supports a transmission speed of more than 1.5.

Digital storage can be connected directly to the decoder or through communication channels such as bus, LAN or telecommunications links. This international standard is intended for non-interlaced video formats of 288 lines of approximately 352 pixels and with image speeds of around 24 to 30 Hz.

This standard specifies the encoded representation of high-quality audio for storage media and the method for decoding high-quality audio signals. It is compatible with current for audio storage and playback. This representation supports normal playback speeds. This standard is made for applications to digital storage media at a total speed of 1.5 mbps for audio and video channels.

The digital storage medium can be connected directly to the decoder, or via other means such as communication lines and the layer of MPEG systems. This standard was created for sampling rates of 32 kHz, 44 kHz, 48 kHz and 16 bit PCM input / output to the encoder / decoder.

The MPEG Standard (Group of Experts in Moving Images)

The united group of photography experts (JPEG) in an ISO / CCITT working group that aims to develop an international standard, ("Compression and digital coding of grayscale or color still images") for general purpose. The purpose of the standard algorithm is to support a wide variety of communications services through images. This dual report structure aims to ensure that ISO manages the same image compression standard.

The JPEG standard equipment specifies two classes of coding and decoding processes: lossy processes and lossless processes. Those processes that are based on the discrete cosine transform (DCT) are called lossy, which allow a substantial compression to be achieved by producing a reconstructed image with high visual fidelity to the source image of the encoder. The simplest coding process based on the discrete cosine transform (DCT) is referred to as the sequential baseline process. This process provides the minimum capacity to carry out different applications.

There are additional processes based on DCT which extend the sequential baseline process to a wider range of applications. In any application environment that uses extended DCT decoding processes, base decoding is required to provide the default decoding capability. The second decoding process is not based on DCT and is provided to meet the needs of applications that require lossless compression (for example X-ray images). The lossless coding and decoding processes are used independently of any of the processes that use DCT.

The Baseline System

The baseline system is the name given to the simplest encoding / decoding capability proposed by the JPEG standard. It consists of uniform quantization and coding. The baseline system provides a sequential reconstruction only. The baseline system encodes an image in one step line by line. Typically the process starts at the top of the image and ends at the bottom; allowing the recreated image to be reconstructed on a line-by-line basis. An advantage is that only a small part of the image is being temporarily stored at any given time. The idea is that a copy with small differences not very perceptible from the original, is almost as good as an exact copy of the original for most purposes. If exact copies are not required, greater compression can be achieved, which translates as low transmission times.

Extended System

Extended system is the name given to a series of additional capabilities not provided by the baseline system. Each series is designed to work in conjunction with, or be built from, the internal components of the baseline system, with the aim of extending its modes of operation. These optional capabilities, which include arithmetic coding, progressive reconstruction and "progressive lossless coding", and others, can be implemented individually or in appropriate combinations.

Arithmetic coding is an optional, "modern" alternative Because the chosen arithmetic coding method is adapted to the values of the image parameters, it generally provides 5 to 10 percent better compression than the chosen Huffman method by JPEG. This benefit is compensated for by the increase in the complexity of the system.

Progressive reconstruction, the alternative to sequential reconstruction, is specifically useful when using image databases with low bandwidth communication channels. For progressive encoding: first, a "rough" image is sent, then the refinements are sent, improving the quality of the "rough" image until the desired quality is achieved. This process is carried out by applications such as image databases with multiple resolutions and various quality requirements, frame freezing in videoconferences, fotovideotex for low speeds.

Progressive lossless coding refers to the compression method which operates in conjunction with progressive reconstruction. In this mode of operation the final stage of the progressive reconstruction results in a received image which is bit by bit identical to the original one.

The JPEG standard (United Group of Experts in Photography) and The JBIG standard (United Group for bi-level images)

In 1988, a group of experts was formed to establish an international standard for bi-level image coding. The JBIG (Joint group for bi-level images), JBIG has developed a document entitled "Progressive compression standard for bi-level images", which defines a method for the compression of bi-level images (that is, an image in black and white). Because the method adapts to a wide range of image characteristics, it is a very robust coding technique.

The JBIG standard operates both in sequential mode and in progressive mode. When a progressively encoded image is decoded, a low resolution image with respect to the original is available first, the image increases in resolution as more data is decoded. Progressive coding has two benefits, the first is that the same image database can serve different output devices with different resolutions each. Only that information in the compressed image file that allows reconstruction to the resolution of the particular output device needs to be sent and decoded.

The other benefit of progressive coding is that it provides subjectively superior images (on a monitor) over communication links of low or medium speeds. A low resolution image is quickly transmitted and displayed, with the improvement of the desired resolution right away. Each stage of improvement of the resolution is built on the image already available. The progressive coding makes it easy for the user to quickly recognize the image being displayed, which makes it possible for the user to interrupt the transmission of an unwanted image.


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