Network multimedia technologies. Topics Concept of multimedia. Hardware required to support multimedia. Audio standards and formats. Standards. Sound wave measurement. Programs for working with Ligos Indeo
Multimedia technologies. Graphic formats
Multimedia(lat. Multum + Medium) - simultaneous use of various forms of information presentation and processing in a single container object.
For example, in one container object (eng. container) may contain text, auditory, graphic and video information, as well as, possibly, a method of interactive interaction with it.
Term multimedia also, often used to refer to storage media that allow you to store significant amounts of data and provide fairly fast access to them (the first media of this type were CD - compact disk.
Classification:
Multimedia can be roughly classified as linear And nonlinear .
Analogue linear method the performance may be a movie. A person viewing this document cannot in any way influence its conclusion.
The nonlinear way of presenting information allows a person to participate in the output of information by interacting in some way with the means of displaying multimedia data. Human participation in this process is also called “interactivity.” This method of interaction between man and computer is most fully represented in the categories of computer games. The non-linear way of representing multimedia data is sometimes called "hypermedia".
As an example of a linear and nonlinear way of presenting information, we can consider a situation such as giving a presentation. If the presentation was recorded on film and shown to the audience, then with this method of delivering information, those viewing this presentation do not have the opportunity to influence the speaker. In the case of a live presentation, the audience has the opportunity to ask the presenter questions and interact with him in other ways, which allows the presenter to deviate from the topic of the presentation, for example, by clarifying certain terms or covering controversial parts of the presentation in more detail. Thus, a live presentation can be presented as a non-linear (interactive) way of presenting information...
Graphic formats
Graphic format is a way of recording graphic information. Graphics file formats are designed to store images, such as photographs and drawings.
Graphic formats differ in the type of stored data (raster, vector and mixed forms), in the permissible amount of data, image parameters, palette storage, data compression technique (for EGA without compression, 256K is required) - DCLZ (Data Compression Lempel-Ziv), LZW ( Lempel-Ziv & Welch), by file organization methods (text, binary), file structure (with a sequential or reference (index-sequential) structure), etc.
A raster file consists of dots, the number of which is determined by resolution, usually measured in dots per inch (dpi) or dots per centimeter (dpc). Very important factor, which influences, on the one hand, the quality of the image output, and on the other hand, the file size, is the color depth, i.e. the number of bits allocated to store information about three components (if it is a color image) or one component (for a halftone non-color image). For example, when using the RGB model, a depth of 24 bits per point means that each color (red, blue, green) has 8 bits and therefore such a file can store information about 2^24 = 16,777,216 colors (Usually in this case we talk about 16 million colors). Obviously, even files with low resolution contain thousands or tens of thousands of points. Thus, a raster image with a size of 1024x768 pixels and 256 colors takes up 768 KB. To reduce file sizes, special algorithms for compressing graphic information have been developed. They are the main reason for the existence of graphic formats.
The vector method of recording graphic data is used in computer-aided design (CAD) systems and graphics packages. In this case, the image consists of the simplest elements (line, polyline, Bezier curve, ellipse, rectangle, etc.), for each of which a number of attributes are defined (for example, for a closed polygon - coordinates of corner points, thickness and color of the contour line, fill type and colors, etc.). The place of objects on the page and their location relative to each other (which one “lies” above and which one below) is also recorded. The vector format is proof of the idea of ancient Greek mathematicians that any shape existing in nature can be described using geometric primitives and a compass.
Each method has its own advantages. Raster allows you to convey subtle, subtle details of images, while vector is best used if the original has distinct geometric outlines. Vector files are smaller in volume, but raster files are drawn faster on the display screen, since to output a vector image the processor needs to perform many mathematical operations. On the other hand, vector files are much easier to edit.
There are many translator programs that convert data from vector format to raster. As a rule, such a problem is solved quite simply, which cannot be said about reverse operation- transformation raster file to vector and even about converting one vector file to another. Vector recording algorithms use unique mathematical models for each supplier that describe image elements.
A number of the most common graphic formats are described below.
1. PCX- The simplest raster format. This format was originally used in Zsoft's PaintBrush program, but later became widespread among editing packages raster images, although still not recognized as an official standard. Unfortunately, during its evolution, PCX has undergone such significant changes that the modern version of the format, which supports 24-bit color mode, cannot be used by older programs. From its very birth, the PCX format was oriented towards existing video adapters (first EGA, then VGA) and therefore is hardware-dependent. PCX uses the RLE data compression scheme to reduce file size by, for example, 40-70% for 16 or fewer colors, and 10-30% for 256-color images.
2. BMP- (Windows Bitmap) under development by Microsoft as compatible with all Windows applications. Applications on the OS/2 operating system have their own version of BMP. The BMP format can save black-and-white, grayscale, index color, and RGB color images (but not two-tone or CMYK color images). The disadvantage of these graphic formats: large volume. The consequence is low suitability for Internet publications.
3. GIF- supports up to 256 colors, allows you to set one of the colors as transparent, makes it possible to save with alternating lines (when viewing, every 8th is displayed first, then every 4th, etc. This allows you to judge the image before it is completely loaded) . Capable of containing several frames in one file with subsequent sequential demonstration (the so-called "animated GIF"). Reducing the file size is achieved by removing unused colors from the palette description and line-by-line data compression (the number of points of a horizontally repeating color is recorded, rather than each point indicating its color). This algorithm gives top scores for images with horizontally extended monochromatic objects. The highly efficient Lempel-Ziv-Welch (LZW) algorithm is used to compress the file.
4. TIFF(target image file format) - was developed specifically for use in page layout applications and is aimed at overcoming the difficulties that arise when transferring graphics files from IBM-compatible computers to Macintosh and vice versa. It is supported by all major graphics and image editing packages and is readable on many platforms. Uses image compression (LZW). The TIFF format is very convenient, but you have to pay for it with the huge sizes of the resulting files (for example, an A4 file in color model CMYK at 300 dpi, typically used for high-quality printing, is about 40 MB in size). In addition, there are several "dialects" of the format that not every program that supports TIFF "understands" easily.
5. JPEG- millions of colors and shades, the palette is not customizable, designed to represent complex photographic images. A variety of progressive JPEG allows you to save images with output in a specified number of steps (from 3 to 5 in Photoshop"e) - first with a low resolution (poor quality), at the next stages the primary image is redrawn with an increasingly better quality image. Animation or transparent color are not supported by the format Reducing the file size is achieved by a complex mathematical algorithm for removing information - the lower the ordered quality, the higher the compression ratio, the smaller the file. The main thing is to choose. maximum compression with minimal loss of quality. The latter identifies and discards data that the human eye cannot see (minor changes in color are not discernible by humans, whereas even the slightest difference in intensity is picked up, so JPEG is less suitable for processing black-and-white grayscale images), resulting in a significant reduction in size file. Thus, unlike the LZW or RLE compression method, as a result of using JPEG technology, data is lost forever. Thus, a file once written to JPEG format, and then translated to, say, TIFF, will no longer be the same as the original. The most suitable format for posting full-color images on the Internet. It is likely that until the advent of powerful lossless image compression algorithms, it will remain the leading format for presenting photographs on the Web.
6. PNG- is still not widespread due to weak advertising, it was created specifically for the Internet as a replacement for the first two formats and, thanks to the patent policy, Compuserve is gradually replacing GIF (see above). Allows you to select a saving palette - gray halftones, 256 colors, true color (" true colors"). Depending on the properties of the image, it is indeed sometimes preferable to GIF"a or JPG"a. Allows you to use a "transparent" color, but, unlike GIF"a, there can be up to 256 such colors. Unlike GIF, compression is performed without loss of quality both horizontally and vertically (the algorithm is our own, the parameters are also not adjustable). Does not know how to create animated videos (the MNG format is being developed).
7. PDF(Portable Document Format) is an example of a mixed format designed to store text and graphics simultaneously. Data is saved in PDF format using the Adobe Acrobat text editor. The LZW method is used to compress graphics.
8. PSD- Adobe Photoshop graphic editor format. It has very great potential. Stores data on various color palettes, transparency, and has the ability to store layered images. At the same time, it is distinguished by its large size.
Vector graphics CDR (CorelDRAW) AI ( Adobe Illustrator) WMF (Windows Metafile) EMF (Enhanced Metafile) |
OTHER FORMATS SWF (ShokWaveFlash) SVG (Scalable Vector Graphics) ICO (Icon) |
Application Programming Interface(Sometimes application programming interface) (English) application programming interface API[hey-pi-ay]) - a set of ready-made classes, functions, structures and constants provided by an application (library, service) for use in external software products. Used by programmers to write all kinds of applications.
Multimedia- a set of hardware and software that allows the user to work interactively with heterogeneous data (graphics, text, sound, video), organized in the form of a unified information environment.
For example, in one container object (eng. container) may contain text, auditory, graphic and video information, as well as, possibly, a method of interactive interaction with it.
Term multimedia also, often used to refer to storage media that allow you to store significant amounts of data and provide fairly fast access to them (the first media of this type were CD - compact disk). In this case, the term multimedia means that a computer can use such media and provide information to the user through all possible types of data such as audio, video, animation, image and others in addition to traditional ways of providing information such as text.
Multimedia can be roughly classified as linear And nonlinear.
An analogue of the linear method of presentation can be cinema. A person viewing this document cannot in any way influence its conclusion.
The nonlinear way of presenting information allows a person to participate in the output of information by interacting in some way with the means of displaying multimedia data. Human participation in this process is also called “interactivity.” This method of interaction between man and computer is most fully represented in the categories of computer games. The non-linear way of representing multimedia data is sometimes called "hypermedia".
As an example of a linear and nonlinear way of presenting information, we can consider a situation such as giving a presentation. If the presentation was recorded on film and shown to the audience, then with this method of delivering information, those viewing this presentation do not have the opportunity to influence the speaker. In the case of a live presentation, the audience has the opportunity to ask the presenter questions and interact with him in other ways, which allows the presenter to deviate from the topic of the presentation, for example, by clarifying certain terms or covering controversial parts of the presentation in more detail. Thus, a live presentation can be presented as a non-linear (interactive) way of presenting information...
47.Using multimedia: advantages and disadvantages. Development prospects.
Multimedia is a set of hardware and software that allows the user to work interactively with heterogeneous data (graphics, text, sound, video), organized in the form of a unified information environment. The main components of multimedia: text, audio, graphic and video information, as well as the method of interactive interaction with it.
The term multimedia is also often used to refer to storage media that allow you to store significant amounts of data and provide fairly fast access to them (CDs were the first media of this type). In such a case, the term multimedia means that a computer can use such media and provide information to the user through all possible types of data such as audio, video, animation, image and others in addition to traditional ways of providing information such as text.
Multimedia presentations can be delivered by a person on stage, shown through a projector, or on another local playback device.
Multimedia games are games in which the player interacts with a virtual environment created by a computer. The state of the virtual environment is transmitted to the player using various methods of transmitting information (auditory, visual, tactile). Nowadays, all games on a computer or game console are multimedia games. It is worth noting that this type of game can be played either alone on a local computer or console, or with other players via a local or global network.
Various formats multimedia data can be used to simplify the perception of information by the consumer. For example, provide information not only in text form, but also illustrate it with audio data or a video clip. In the same way, contemporary art can present everyday, everyday things in a new way.
In order to post a video on YouTube or Yandex.Video, the user does not need knowledge of video editing, encoding and compression of information, or knowledge of how web servers work. The user simply selects local file and thousands of other users of the video service have the opportunity to view the new video.
Multimedia finds its application in various fields, including advertising, art, education, entertainment, technology, medicine, mathematics, business, and scientific research.
In education, multimedia is used to create computer-based training courses and reference books, such as encyclopedias and collections. In the industrial sector, multimedia is used as a way to present information to shareholders, management and colleagues. Multimedia is also useful in organizing staff training, advertising and product sales around the world. In mathematical and scientific research, multimedia is primarily used for modeling and simulation. For example: a scientist can look at a molecular model of a substance and manipulate it to make another substance. Doctors can also be trained through virtual surgery or simulators of the human body affected by a disease spread by viruses and bacteria, thereby trying to develop techniques to prevent it.
A multimedia textbook is a way to conduct the same or almost the same dialogue with the student as the teacher. In this textbook, the student can see things that cannot be printed on paper. The multimedia textbook “brings to life” chemical molecules and human organs, allowing you to see them as they are in reality, and not in the form conditional diagrams and drawings. And, what is important in our time, illustrative files of multimedia aids can, in some cases, quite successfully replace expensive collections of reagents and drugs, i.e. bring direct economic benefit.
Multimedia is a set of hardware and software that allows a person to communicate with a computer using a variety of natural media: sound, video, graphics, texts, animation. In a broad sense, the term "multimedia" means a spectrum information technologies using various software and technical means in order to most effectively influence the user (who has become at the same time a reader, a listener, and a viewer).
Multimedia technology has received one of the widest areas of application in the field of education, since information technology based on multimedia can, in some cases, significantly increase the effectiveness of learning. It has been experimentally established that when presenting material orally, a student perceives and is able to process up to one thousand conventional units of information in a minute, and when the visual organs are “connected”, up to 100 thousand such units.
There are many positive aspects of using information and telecommunication technologies in education. Negative aspects:
Curtailment of social contacts;
Reduced social interaction and communication, individualism; Individualization limits live communication between teachers and students, offering them communication in the form of a “dialogue with a computer.” The student does not receive sufficient practice in dialogical communication, formation and formulation of thoughts in a professional language.
Complex ways presentations of information distract students from the material being studied. If a student is presented with different types of information at the same time, he will be distracted from some types of information to attend to others, missing important information.
Excessive and unjustified use of computer technology negatively affects the health of all participants in the educational process.
Virtual reality tools will develop to influence as many human senses as possible. For example, the Latypov brothers have already developed a “virtual sphere” that rotates, simulating the movement of a person in the virtual world - thus, his movement requires real muscular effort, and not just pressing a button or turning a joystick. There are projects that involve saturating virtual reality with smells appropriate to the environment.
48. Postal systems. Email addresses. OutlookExpress application, TheBat!
Electronic mail (English e-mail, from English electronic mail) - technology and the services it provides for sending and receiving emails over a computer network.
The advantages of e-mail are: addresses of the form user_name@domain_name that are easily perceived and remembered by humans; the ability to transfer both plain text and formatted, as well as arbitrary files; sufficiently high reliability of message delivery.
Disadvantages of e-mail: the presence of such a phenomenon as spam (mass advertising and viral mailings); the theoretical impossibility of guaranteed delivery of a specific letter; possible delays in message delivery (up to several days), restrictions on the size of one message and on the total size in the mailbox.
Currently, any novice user can create their own free email account; just register on one of the Internet portals.
A mail system is a technology designed to work with e-mail messages Online.
The world's generally accepted email exchange protocol is SMTP (Simple mail transfer protocol). Mail is transferred between sites using mail forwarding programs (eg OutlookExpress, TheBat!)
Within a given mail system (usually located within the same organization) there can be many mail servers that perform both mail forwarding within the organization and other e-mail-related tasks: spam filtering, scanning attachments with an antivirus, providing auto-reply, archiving incoming/outgoing mail .
Email address is a record that uniquely identifies the mailbox to which an email message should be delivered.
The address consists of two parts, separated by the “@” symbol. The left side indicates the name of the mailbox, often it coincides with the user login. The right side of the address indicates the domain name of the server on which the mailbox is located.
OE is a program for working with email and newsgroups from Microsoft. Supplied as part of operating rooms Windows systems, and also together with Internet browser Explorer. The name OE suggests that this program is a lightweight version Microsoft Outlook- an organizer from Microsoft, which also contains functions for working with email. In fact, there is little in common between the two programs. In addition, Outlook, unlike OE, until version 2007 did not have the function of working with newsgroups.
OE is based on earlier email and news software, the Microsoft Internet Mail and News package that came with Internet Explorer 3.0.
OE is used on both home and office computers, but it is more convenient for home users who open email via the Internet.
OE works with virtually any standard Internet system:
Simple Mail Transfer Protocol (SMTP);
Post Office Protocol 3 (POP3);
Internet Mail Access Protocol (IMAP).
OE allows you to choose the background and graphics for your messages. Built-in templates provide the ability to illustrate messages.
TV is a paid program for working with email for Windows OS. Developed by the Moldovan company RITLabs. The TV program is popular among Russian users and users from the former republics of the USSR.
It has a fairly developed system for filtering and sorting messages, as well as a system for connecting additional extension modules (plugins) designed (if required) to integrate anti-virus and anti-spam programs from various manufacturers. The necessary plugins can be supplied with the antivirus or downloaded from the website of the developers of this module.
Supports protocols: SMTP. POP3, IMAP. Supports big number encodings. There are mechanisms for filtering messages, their automatic processing, templates and capabilities for organizing mailing lists.
Hello my dear readers!
Did you know that every file or document located on your PC, be it a picture, an audio file or some kind of video, has its own extension, that is, a file type. Each file type belongs to a corresponding category:
You can click on any category to go directly to it.
Remembering myself about 3-5 years ago, I had no idea about the number of file types that I know about now. As I mentioned in the article About the Author, I received higher education at the STEP Academy in Kyiv. But before going there, you had to go through an interview and pass a short test exam. So, one of the exam tasks was to write 5 - 7 types of files related to images with a description of their occurrence and properties. You won’t believe it, but apart from jpeg, gif and png, nothing else came to mind, but even knowing these types of files, I didn’t know how they differ and how... . Sad isn't it? And this is a man who was going to become a web designer. Well, so that you are not so far from knowing basic file types and can, if necessary, tell someone who needs what it is and what it is eaten with, I am writing this article.
There is simply great amount file types and extensions, and a day would not be enough to describe them all. Therefore, I will take only the most used categories and, of course, the most common file types related to these categories. Let's start with audio.
Drawings, images.
So, the most common types of image files are: JPEG, TIFF, GIF, RAW and the most common bmp file. All these files belong to Raster images, but there are also files and Vector images such as: ai, cdr, cmx, eps, fla. And now a few words about raster and vector.
Raster graphics– this is graphics in which data about a drawing is stored in pixels, where each pixel has its own color value corresponding to its model (RGB, CMYK, LAB, HSB). Basically these are graphics that are used on digital media. It has the so-called blur property when enlarged - loss of quality. Vector graphics- this is graphics that have mathematical data that operate not with points, but with geometric figures, which actually make up the drawing itself. When we apply zoom (increase) to such a drawing, the drawing is practically redrawn from scratch, which does not cause any loss of quality.
Well, now let's take a short excursion into the types of these types of graphics.
JPEG– stands for Joint Photographic Experts Group, that is, the name of the company that developed it. This file is compressed, with slight loss of quality, it is the most common graphic format for today. You can open it: any viewer or graphics editor, as well as any of the currently existing browsers.
TIFF- Tagged Image File Format, which in English sounds like this - a format for storing raster images graphic images. Probably one of the most common file types used in printing houses, as well as in faxes and scanners. Just like jpeg, you can open it with most graphic editors.
GIF– has the meaning Graphics Interchange Format File, it can easily store a certain sequence of raster images, which we often call nimation. This type of file is created primarily by video or graphics editing programs. The format is used in digital advertising, as well as visual design video. You can open it with any browser, and programs for processing and editing graphics or video editing.
RAW— Raw Image Data File, which means unprocessed. This is data obtained from the matrix of high-quality cameras, without any processing or compression, and has a lot of weight. The advantage of such a file is its subsequent processing. Opened and processed special programs or powerful editors such as Adobe Photoshop, JRiver Media Center or Rawstudio.
Ai– this format already refers to vectors, created by Adobe Illustrator. It is important to take into account the fact that a file created in more new version will not open in a later one, or it will open but with the loss of some data. This format creates high-quality drawings, but unfortunately is not compatible with others
Cdr- This vector type files belongs to the CorelDraw program. Which is no less popular than the same Illustrator. As is the case with Illustrator program has many versions, and each format of a new version cannot be opened in a later version. The quality of saving a drawing in this format is excellent, but there are pitfalls here, namely, the format is difficult to read in many similar programs working with vectors.
Eps– The format can easily be considered universal, since programs such as Macromedia FreeHand, CorelDraw, Adobe Illustrator and many other analogues can easily work with it. This vector graphics format also has its own versions, and here you need to be careful, since not every program will be able to open newer versions of this extension.
Wmf– Well, how can Microsoft manage without its own developments in vector graphics? This type of vector graphics is used exclusively in Microsoft Windows. Although any other program can open it, you shouldn’t bother with it, since it does not have the quality of the drawing that is present in the examples above.
Video files:
Let's move from graphics to video. I already wrote an article about, in which I mentioned video formats.
VHS- a throwback to the past, a video format that was used on video cassettes. (Pleasant memories, when a whole crowd of friends sat at someone’s house and enthusiastically watched a bought action film on cassette), oh, there was a time, now everything is not so and there are fewer friends with whom you can sit like this in a group near the box.
DV (Digital Video)– a format developed by world video recording studios. This is also a cassette series, but of a higher quality and which was worked on by more than one leading company, such as Panasonic, Philips, Hitachi.
AVCHD– video recording format high definition and characteristics, such parameters as 720p, 1080i and 1080p, the media in this case served Blu-ray discs, as well as memory cards. We all know it as HD video or HD picture quality. This is the most modern form of digital video. A format that has begun to be used everywhere, and there is probably no such person who does not know what DH video quality is.
MPEG-1– Compression format for media such as CD. Video format does not produce High Quality pictures and has an extension of 352x240, isn’t it funny? Seeing him in action these days is very rare. But you know what it is.
MPEG-2– This format has become widespread on DVD discs; it allows you to shoot on HDD and Flash cameras. Previously, this format was used in some DVRs, and AXIS Communications also used it.
MPEG-4– A video format that combines well-known codecs: DivX, XviD, H.264, etc. Due to its compression, it has a good data transfer rate. Well, it’s worth mentioning that a large number of DVD players support it.
HD (High Definition)– The most powerful video format, having two types of resolutions called: HD1 (1280x720) and of course HD2 (1440x1080), respectively. But to appreciate this quality, you need a widescreen display of LCD monitors or TVs.
AVI– Dear readers, this is not a format at all, as we all used to think, it is a Microsoft development – a container that can easily store 4 streams, such as video, audio, text and midi. Impressive, isn't it? I am already silent about the scale with which the whole world uses it. Now I'll open it little secret. You've probably noticed that AVI files are not always read by your device, sometimes there is no sound, sometimes there is no video, but there is sound. So the reason is that the AVI container may contain a codec that your reading device does not have. To solve this problem, I advise you to download and install the K-Lite assembly on your PC Codec Pack. You will forget about your problems forever.
WMV– The result of the diligence of Microsoft, this video format is their own development, the result of a video processed in Movie Maker. It will open in any build of Windows without problems, it is easy to encode it into another format using the same program that I wrote about in the Installation and configuration post Format programs Factory.
MOV– We talked about the Microsoft format, it’s time to mention Apple, so MOV format and is the creation of this company. At its core, the format is not bad and can contain both graphics and animation, as well as 3D. But it has a drawback: it is not always reproduced by standard players. Sometimes you have to download and install QuickTime Player.
MKV– It is similar to the AVI format and can easily contain audio, video, various menus, text, etc. True, there is one significant difference between it and AVI; its code is open and accessible to anyone. Although it is not as popular as AVI, it has good prospects.
3gp– Well, how can we not mention this format, since we are all familiar with it from our first phones, when the presence of a 20-second video on a mobile spoke of your coolness more clearly than any words. You guessed it right, this is the format of mobile devices. In which everything is compressed and distorted to the point of disgrace. Today it can only be found on old wap sites.
And now about the formats used on the Internet:
FLV– The main flash video format for posting and distributing videos on the Internet. It is used by such platforms as YouTube, RuTube, Yandex video, Google video and many others.
SWF– the result of an animation created using Adobe Flash. Will be played by all browsers using the installed Flash plugin Player.
If we draw a parallel between FLY and SWF, then SWF is a flash video, but FLV is a flash video, well, something like that.
RAM, RM, RA is a unique development of the company RealNetworks, known for its scandal for developing a program capable of copying licensed discs that are protected from overwriting to the user’s PC. So this format is used for television broadcasting on the network, which of course cannot but rejoice. With its help we can watch IPTV.
Let's move on to the category of audio formats.
What is bitrate?!– this is the amount of information transmitted over a certain period of time. The essence of its principle is how much information we can devote to each second of playback of our audio file. It is generally accepted to use Kbps or Mbps as a unit of measurement, the second option is less common, you understand why. Let's now move on to the formats themselves.
WAV- This is one of the highest quality audio formats that convey sound quality without compression or loss. True, there is one drawback to this quality: such files take up a lot of memory, which is not entirely practical for websites on the network. The quality will usually be from 192 Kbps to 320 Kbps.
WMA– developed by Microsoft in order to compete with the well-known mp3 format. You can see for yourself what came of it. Do you have all the tracks in WMA format on your phone? I knew it. Although they were partially able to achieve a small file size and more normal sound quality.
FLAC– a format for everyone. This type of audio file is perceived adequately by all platforms and media without exception. It can be compared with the principle of WinRAR, which we know, because this format first compresses the file, and during playback it seems to decompress.
MIDI– Globally different from its brothers. These are not just sounds, but a whole set of different commands for the sound of certain sounds. There is not a single recording studio that can do without this format. There is just a great article on this topic, where everything is broken down piece by piece; I advise music lovers to read it.
MP3– Here, as they say, comments are unnecessary. The most common audio format, both online and offline. It is an undeniable fact that this is the most compressed format, and this has the advantage of taking up very little space. But where there is compression, there is a correspondingly greater loss of quality and subtlety of sound. When compressed, everything that is almost imperceptible to the human ear is cut out of the track, so we see virtually no difference between it and the same WAV.
AIFF– format for machines running Mac OS. This file type also works without compression and therefore has no loss of sound quality, therefore it is used along with WAV and SDII in professional audio and video applications.
Text and document formats.
Doc– The most common format of the well-known program from Microsoft Word, which is part of the Microsoft Office software package for Windows. Its disadvantage is poor compatibility with other text editors, and even among themselves they are not entirely compatible in versions such as 2003, 2007 and 2010.
FB2– Text format of e-books, in Lately is gaining wide scale and is used in many readers. One of the high-quality readers is Cool Reader.
PDF– A very common document. A format that can contain both text and graphic elements. It was developed by adobe systems. Supports both raster and vector graphics, which is a definite plus and convenience. Most word processing programs easily export data to a pdf document.
RTF– The format is still from the same Adobe company, although it was originally developed by both Microsoft and Adobe. Text formatting is built using meta tag formatting. It can be opened and saved by WordPad, OpenOffice, TextEdit. Although there is no mass appeal in this format.
Sincerely AHDEPC.
In this article, we will look at video and audio conversion tools, understand multimedia formats, and select the best tools for converting files.
Whether we like it or not, it cannot be that the world of digital entertainment is entirely dominated by a single format. The same MP3 today is successfully replaced by OGG and AAC, AVI - MPG, FLV, etc. In fact, there is no significant problem with such diversity.
Separating media formats is a necessity. Each format has its own specific feature, a reason why it can or should be used and not any other. Often it all comes down to savings - in our case, saving hard drive space. In each case, there is a format that is most advantageous in a given situation and less optimal. Today we will do the following: firstly, we will remember which multimedia formats are most in demand when converting video/audio and, secondly, we will consider the required set. We emphasize: we consider only multimedia formats - namely sound and audio.
Part I. Formats and codecs for conversion
Since it is impossible to embrace the immensity, we will touch only on the most common and popular multimedia formats, codecs, and give them short description and an explanation of when they are best used. During the description, we will also present a list of programs that are in some way related to this format. We will not provide links; all programs can be found on the website.
Video standards
MPEG-1
MPEG-1 is a standard adopted by the MPEG group of experts (Moving Picture Experts Group - a group of experts in the field of video). On this moment MPEG-1 video is used on Video CDs (VCD quality is closest to the quality of VHS video cassettes).
Initially, the use of MPEG-1 video is limited to a bit rate of 1.5 Megabits/s and a resolution of 352×240. However this standard allows you to use any resolution up to 4095x4095.
MPEG-2
The MPEG-2 standard is used for broadcasting, including satellite broadcasting and cable TV. It has strict restrictions on resolution (no more than 720 × 576), frame rate (25 fps and 29.97 fps), bitrate, etc.
MPEG-3
Audio and video coding standard for high-definition television (HDTW - High-definition television) with data transfer rates from 20 to 40 Mbit/s. Work on MPEG-3 was stopped after the modification of MPEG-2 (when the MPEG-2 standard began to cope with video processing no worse than MPEG-3).
MPEG-3 should not be confused with the MP3 music format (MPEG-1 Part 3 Layer 3/MPEG-1 Audio Layer 3).
MPEG-4
MPEG-4 is used to compress digital audio and video. Designed for broadcasting on the Internet (streaming video, video telephony), encoding and recording films on CDs, (video telephone) and broadcasting.
Video codecs
DivX (Digital video express)
The most famous video codec for the Microsoft Windows and Mac OS X platforms, which is used to compress most films today. Compression allows you to place an hour and a half of video material on 1 - 2 CDs. It is distributed in two versions: DivX and DivX Pro. DivX is free (AdWare), you can use it without restrictions, the second one is paid. The “Pro” console costs $19.99 along with additional package features and advantages over the free version. This:
Best compression (about 25%) of video,
- support for GMC (Global Motion Compensation) technology, which improves video quality and slightly improves the compression ratio,
- DivX Pro provides full support bidirectional coding (B-frames),
- includes additional tools for video encoding.
Programs for working with DivX
DivX Player is the official player from the creators of the DivX video format.
DivX Subtitle Displayer- a program for displaying subtitles when DivX playback video.
DivFix- utility for recovering damaged DivX video.
DivX AntiFreeze– Some video clips have damaged frames. AntiFreeze prevents video from freezing.
Dr. DivX- a program for transferring video from various sources (from a file, from a video camera, TV, etc.) into video files in the DivX format. The utility can work with MPEG1, MPEG2, MPEG4, AVI and WMV.
MPEG-4 video conversion library, distributed under the GNU General Public License. Unlike the DivX codec, which is released only for the Microsoft Windows and Mac OS X platforms, Xvid is a cross-platform product (used on all platforms and operating systems for which the codec source code can be compiled).
As you can see, the name of the codec is “reversed” from DivX. In practice, Xvid is an alternative to DivX. The codec is different fast speed work and acceptable quality Images. Configurable via third party programs, and through own window settings.
Programs for working with Xvid
Today, there are a large number of varieties (compilations) of Xvid, which with equal success allow you to view and convert videos to phones, disks, and other media.
Koepi XviD is one such compilation.
Nic's XviD is another popular build that includes Xvid.
Windows Media Video
Coding system developed by Microsoft. Included in the Windows Media Pack. It exists in several versions: Microsoft MPEG -4 Video Codec, Windows Media Video 9, etc. Despite the fact that WMW cannot compete with DivX video, it is actively used in the development of media and gaming applications for the Windows platform.
Programs for working with WMV
Windows Media Encoder - codec and shell for the encoder.
Windows Media Video 9 VCM - similar to the previous one, but does not include a graphical shell.
Ligos Indeo
Initially, the Ligos Indeo codec was developed by Intel, but then it was taken for further development by Ligos. Now the codec allows you to view videos at different bitrates, respectively, with adaptive quality. Ligos Indeo supports the MMX processor instruction (although DivX has much more supported instructions).
Programs for working with Ligos Indeo
Intel Codec Installer - supplies the so-called I263 codec, which makes it possible to play e-cards and videos in the Ligos Indeo format.
Intel JPEG Library Video Codec (ijlvid) - special driver, based on the Intel JPEG library, supporting decompression in RGB24 and compression of RGB24 and YUY2 formats.
Intel Music Coder - thanks to this package you can listen to AVI video with sound encoded in IMC.
Apple QuickTime
This free codec package is quite well known not only to users Apple products. Available for download from the Apple website (www.apple.com) along with a program for playing video in quicktime format, which is called QuickTime.
Programs for working with Apple QuickTime
QuickTime is a program for playing MOV/QT files. Unfortunately, ported to Windows version has many disadvantages (inconvenient interface, unjustified resource consumption, etc.).
QuickTime Alternative - an alternative to QuickTime. The package contains codecs and programs for playing video in quicktime format.
DScaler MPEG
Programs for working with DScaler MPEG
GPL MPEG -1/2 DirectShow Decoder Filter, Stinky’s MPEG -2 Codec - allows you to play MPEG -1 and MPEG -2 format files in Windows Media Player and other players.
Dscaler is a program for capturing and processing MPEG video.
TrueMotion VP6
TrueMotion VP6 is a competitor to MPEG4 codecs DivX and Xvid. At low bitrates it gives a noticeably better picture than the latter. Recently, many videos are encoded in VP6 and have the FLV format. Instead of TrueMotion VP6, an improved version is offered - VP7.
Programs for working with VP6
Browsers with Flash support, video players.
Free FLV Converter and Any Video Converter- respectively paid and free converters from FLV to other video formats.
Advice. If you want all of the above packages installed on your computer and do not want to download each codec separately, download and install the universal and free K-Lite Pack (www.codecguide.com). It is distributed in 5 versions:
- Basic - contains the required minimum: DivX and Xvid codecs.
- Standard - more expanded compared to the previous package. Allows you to play common and less well-known formats.
- Full - a package primarily intended for video encoding/decoding. Includes all the tools needed for these operations.
- Corporate - enterprise solution. Very similar to the Full package.
- Mega - Full version plus a set of Real Alternative codecs.
Video formats
MPG
Basic MPEG format. A file with this extension contains MPEG1 video + MP2 (MPEG -1 layer 2) or, less commonly, MP1 audio.
VOB
MPEG file format on DVD-Video discs. It is the same MPG, but with subtitles and a non-MPEG audio track (this can be AC-3 audio.
AVI
AVI (Audio Video Interleaved - Audio + Video + Layered) is a format developed by Microsoft. Most often used for storing MPEG4 video. Microsoft currently recommends using ASF instead of AVI.
A.S.F.
ASF (Active Streaming Format) is another Microsoft development. There are two versions of ASF - v1.0 and v2.0. For some time now, ASF files have had the extension WMA or WMV.
MOV/QT
Format developed by Apple. QuickTime is the recommended format for MPEG4. MOV files come with the extension MPG or MP4. The video and audio in these files are nothing but MPG and AAC.
RealMedia
Format streaming. It is characterized, on the one hand, by low image quality at high bitrates and, on the other, by a good degree of compression. This allows you to play music and videos on the Internet in “demo” quality. RealMedia files have the extension *.RM, *.RAM or *.RMVB.
Audio formats (abbreviated)
A.S.F.
ASF (Advanced Streaming Format, not to be confused with the video format of the same name) is an audio standard for OS Mac. Big size file and quality close to AudioCD.
FLAC (Free Lossless Audio Codec)
FLAC (Free Lossless Audio Codec) - audio compression up to 50 percent without loss of sound quality.
WAV
Standard format for Windows. The sound is stored without loss of quality and, accordingly, the file takes up a lot of disk space.
FLAC(English Free Lossless Audio Codec - free lossless audio codec) is a popular free codec for audio compression. Unlike lossy codecs Ogg Vorbis, MP3 and AAC, does not remove any information from the audio stream and is suitable for both listening to music on high-quality sound reproduction equipment and for audio collections. Supported by many audio applications.
AIFF
File format for Mac platforms OS. It is characterized by high sound quality, since it is not subject to compression (the so-called loseless format).
Monkey's Audio is a popular lossless digital audio encoding format. Distributed free of charge along with open source code and a set of software for encoding and playback, as well as plugins for popular players. Monkey's Audio files have extensions APE for storing audio and APL for storing metadata.
WMA (Windows Media Audio)- a format developed by Microsoft for storing and broadcasting audio information. Initially WMA format was intended as an alternative to MP3, but today Microsoft opposes it to another format - AAC. Files compressed with this codec are about a quarter larger than OGG, although the WMA format has good compression capabilities, which allows it to outperform MP3 in sound quality at low bitrates.
MP3 lossy compression format. In short, the sound compression algorithm is as follows: sound information that a person cannot perceive is removed from the recording.
Objectively, MP3 cannot be called the “best” or “optimal” format. Its main advantage is that the format is so widespread that there can be no problems with software/hardware incompatibility. The compression level can be varied, including within a single file. The range of possible bitrate values is 8 - 320 kbit/s. Most music distributed illegally on the Internet has a bitrate of 128 to 256 (in rare cases 320) kbps. This quality is quite sufficient for introductory listening, but for storage in an audio collection we recommend using OGG or AAC. In terms of size/quality ratio, AAC wins.
A.A.C.
AAC (Advanced Audio Coding) is the most likely alternative to MP3 (as they also say, “the result of the evolution of MP3 files”). The format is promoted by Apple - in particular, in the famous online music iTunes store. Sometimes AAC is found on other music sales services.
At AAC compression loses less than MP3, audio information. As a result, when same size AAC is superior in quality to MP3. Moreover, in this format it is possible to compress audio without loss of quality (ALAC profile). Other features compared to MP3:
Frequencies from 8 Hz to 96 kHz (MP3: 8 Hz - 48 kHz)
- Up to 48 audio channels
- Greater encoding efficiency with constant audio flow
- Greater coding efficiency with varying audio streams
File format:
M4A- unprotected AAC file,
M4B- AAC file that supports bookmarks (used for audiobooks and podcasts),
M4P- protected AAC file. Used in online stores to protect a file from copying.
OGG
Ogg Vorbis is a relatively new audio compression format (officially introduced in the summer of 2002). Since the license under which it is distributed is completely open, OGG has taken root as the main format in Linux environment. OGG allows you to compress tracks in listening quality (8kHz-48.0kHz, 16+ bits, bitrate from 16 to 128 kbps per channel). This puts the format on par with AAC, WMA and, of course, MP3. The psychoacoustic model used in Vorbis is close to MPEG Audio Layer III, but the practical implementation of this model is somewhat different. Therefore, when listening to OGG files, you can notice a noticeable difference (both at high and low bitrates) compared to other formats.
BELARUSIAN STATE POLYTECHNIC ACADEMY
FACULTY OF INSTRUMENT ENGINEERING
Department of ENGINEERING MATHEMATICS
Prepared by student: Beskarovainy A.L.
Group 113039
Head of work: Anisimov V. Ya.
Minsk 2000
CONTENT:
MULTIMEDIA. SOUND FILE FORMATS.
Multimedia is a universally accepted term for an interactive tool for working with graphics, animation, sound and video. Multimedia brings brilliance to presentations, painting and games, and also makes learning fun. It turns a computer from a desktop system with a keyboard and monitor into a kind of “spacecraft” equipped with speakers, a microphone, headphones, joysticks and CDs.
What is multimedia?
Multimedia allows you to work on your computer with all types of information, not just text or ordinary pictures. Multimedia is digital information that has more ample opportunities than its other types.- Since sound and graphic information recorded in digital form, it can be copied without loss of quality.
Digital information Can be compressed to a minimum for storage.
You can store a huge amount of information on a CD-ROM, and the CD-ROM itself takes up very little space.
Interactive computer programs using digital media systems are excellent teaching tools.
- Playback systems. These systems typically include a multi-speed CD-ROM drive, a sound card, speakers, and a relatively high-definition video system. It also wouldn't hurt to have a decompression card that works with digital information.
Author's systems. (systems used to create media system files). Authoring systems typically include components such as microphones and video cameras to record audio and capture video images. They are also high-speed, high-capacity hard drives capable of storing and serving the large volumes of information required for digital video.
But now, when such graphical user interfaces as Windows95/98(SE)/ME/NT/2k appeared. , and significantly more powerful personal computers, applications began to appear that provided the ability to use animation effects, sound and video. At the end of 1980 people began composing music on the computer, combining animation and sound, creating immersive multimedia presentations with sound and moving pictures. The equipment, however, was expensive and the results often fell short of expectations. Windows3.1 and DOS did not have enough resources to support multimedia systems, so the pictures on the screen moved very slowly.
Multimedia and Windows 95/98(SE)/ME/NT/2k/XP.
Thanks to Windows, everything has been transformed. It supports tools that significantly improve your experience with multimedia.- Windows95/98(SE)/ME/NT/2k. is a 32-bit, multi-tasking, multi-threaded operating system. This means that Windows supports multitasking, playing multimedia presentations, and interactive user interactions.
During installation, Windows automatically detects the configuration of multimedia devices.
Windows applications support multimedia. You can create compound documents, i.e. documents that include sound, video, graphics, diagrams, pictures and other elements of various applications.
Windows supports Sony/Philips CD+ and Kodak PhotoCD CD formats, and makes it easy to run programs and play discs from a CD-ROM drive.
The Windows video standard is widely supported in the computer industry. Developers of multimedia products can distribute their products with peace of mind knowing that it will run on Windows.
Multimedia products designed for Windows tend to be high quality products because Windows supports large video windows and Windows' 32-bit architecture improves data flow.
Windows supports Sony VISCA interface. This means that in applications you can use so-called VCR buttons (VCR - English abbreviation from Video Cassette Recorder - video recorder, i.e. buttons, functionally similar to the rewind, playback and other buttons on audio and video playback devices) when playing laser discs.
The gaming experience on Windows has been greatly improved with a new software graphical interface.
Windows supports many different standard industrial audio and video devices for compressing information when recording it to a file, as well as decompressing it during playback (the so-called codec devices). The codec reduces the size of multimedia files and allows them to be distributed in various formats.
Multimedia systems
Additional peripheral devices for a computer in the mid-80s included disk drives, scanners, printers, and modem-type communications devices. The 1990s saw the advent of sound cards, video cards, CD-ROM drives, and high-speed communications that allowed you to connect to a data service that streamed multimedia to you over the wire.Listed below are minimum requirements to run multimedia under Windows.
-
Intel processor 80486 (Pentium recommended for digital video applications).
PCI bus for data transfer for the disk controller and video card.
Large hard drive (from 300 MB). High-quality digital video systems require gigabytes of memory.
CD-ROM with a speed of at least 4 with sound control on the front panel.
Sound card providing 11.025 quantization frequencies; 22.05 and 44.1 kHz for stereo sound. Also required are multi-voice and multi-timbral devices capable of receiving multiple sources at the input and presenting stereo sound at the output.
Video equipment that supports high monitor resolutions. Microsoft recommends for best quality Video presentation use VESA or PCI video card. Recently, AGP adapters have become popular.
IBM compatible analog joystick port.
A MIDI port that supports established standards for data input, output, and transmission. Some sound cards contain MIDI synthesizers, but generally you connect to an external MIDI synthesizer that looks like a keyboard.
The above components are necessary for playing and recording multimedia. However, if you want to create multimedia clips yourself, you may need additional equipment.
Multimedia types and standards
Multimedia information is stored in the form of files in a special format containing sound, video, or MIDI files.Audio media (sound media) is stored primarily in two formats, WAV and MIDI. Most WAV files require a lot disk space, but they can be played using any sound card. MIDI files take up significantly less disk space, but can only be played on MIDI-compatible devices. Nowadays, almost all cards are capable of playing MIDI files.
Visual media refers to animation files and video files.
Animation. On Windows, if you have the appropriate application, you can create images that move across the screen. There is no standard animation file format, but many developers are simultaneously developing the production of both animation tools and playback equipment. Animation can be accompanied by sound files of different formats.
Video. Video for Windows is a video standard for Windows. You can record a movie from a camcorder or laser disc to your computer's hard drive and save it as a file in AVI or MPG format. Compression is only required for high-quality video and efficient storage.
About audio media
Audio recording and playback applications were among the first known multimedia applications for the personal computer. By adding a sound card, you can record a message delivered by voice, save it as a file on disk, and transfer it to another computer where it can also be played back. You can also record music and audio for computer presentations.There are two ways to record sound:
- Digital recording is where real sound waves are recorded and converted into digital data.
MIDI recording, generally speaking, is not actual sound, but a recording of keystrokes or other operations performed on synthesizers or MIDI-compatible electronic musical devices. A MIDI file is the electronic equivalent of playing a piano.
Digital recording
The sound card converts the sound output into digital information by measuring the sound thousands of times per second. Digital audio is stored in files with the WAV extension. When recording audio, an analog-to-digital converter converts the sound into digital data. When playing sound, a digital-to-analog converter converts digital data into an analogue sound wave.Sound is vibrations that form a wave with the appropriate amplitude and period, as shown in Fig. 1. Amplitude expresses the height of the wave, or loudness of the sound. A period is the distance between two sound waves. Finally, frequency shows the number of cycles per second and is measured in Hertz. For example, one hundred cycles per second is 100 Hz. A person can perceive sound with a frequency from 20 to 20,000 Hz, and all produced sound reproducing and recording equipment is designed for this frequency range.
Rice. 1. Sound wave measurement
In order to record sound and store it on a digital device such as your computer, the sound is quantized, i.e. splitting a sound wave into certain time intervals. The sound wave shown in Fig. 2 was divided into 16 intervals. If we assume that the duration of the sound wave is one second, then its quantization frequency is 16 Hz.
Rice. 2. Wave quantization at a quantization frequency of 16 Hz
Typically, such a low quantization frequency is not used. Even digital audio with a quantization frequency of 100 or 1000 Hz will not be recognized during playback. This happens because the digital representation of the wave in this case is not smoothed. Filtering equipment smoothes the wave, but the best way to obtain a high-quality digital recording is to increase the quantization frequency. Please note that this increases the amount of data stored, which will require more disk space.
Multimedia standards correspond to three types of quantization frequencies: 11.025; 22.05; 44.1 kHz. The quantization frequency depends on the audio being recorded: 11.025 kHz is suitable for voice recording, but a quantization frequency of 44.1 or 48 kHz is required to obtain a high-quality recording. However, increasing the quantization frequency increases the file size and the required disk space to store it. The formula for calculating disk space will be given below, but first you need to understand one variable - the number of bits used to store quantization information.
Each interval contains information about a small time segment of the sound. The number of bits to record each interval determines the accuracy of the sound wave approximation, but increases the size of the file in which the digital audio is stored. 4-bit binning provides vertical division of the sound wave amplitude into 16 levels, and 8-bit binning provides 256 levels. High-quality recording requires 16-bit amplitude binning, which defines 65,536 amplitude levels.
The previous discussion was about a smoothed sound wave, but a real wave is not smoothed - it is made up of many different frequencies that together create the timbre of the sound. Timbre is the unique sound inherent to an instrument. For example, the vibrations of the string and the resonator determine the sound of a violin (the unique sound of a Stradivarius violin is the result of the addition of valuable substances to its polishing). The violin produces a whole complex of sound waves, as shown in Fig. 3.
Now you see the importance of increasing the quantization frequency and bit depth sound card when recording sound. You need to know not only the amplitude of each selected interval, but also everything that happens to the wave per unit time. Increasing the quantization frequency and bit depth of the sound card ensures high-quality sound recording, however, it should be remembered that this leads to a significant increase in the disk space required to store the recorded sound. Fortunately, if you are recording voice, there is no need to use a higher quantization frequency and bit depth of the sound card.
Rice. 3. real sound waves have a very complex shape and to obtain their high-quality digital representation requires high frequency quantization
Below is the formula for calculating the required disk space for storing digital audio:
For a second
In table 1. shows the required disk space to store a one-minute audio recording for each quantization frequency at 8 bits. The first line in the table corresponds to a low-quality voice recording, and last line– standards established for digital audio compact discs.
Table 1. Storage requirements sound files
Note that a high quantization frequency and bit depth are not required if the sound was recorded and played on equipment more Low quality. For example, a pocket microphone records much lower quality audio than recording at a sampling rate of 44 kHz. If you have a high-quality recording, then high-quality equipment is required to play it back.
Sound and types of sound files
Sound is a physical natural phenomenon that propagates through air vibrations and, therefore, we can say that we are dealing only with wave characteristics. The task of converting sound into electronic form is to repeat all of its wave characteristics. But the electronic signal is not analog, and can be recorded through short discrete values. Even though they have a small interval between each other and are practically imperceptible, at first glance, to the human ear, we must always keep in mind that we are only dealing with the emulation of a natural phenomenon called sound.This recording is called pulse-code modulation and is a sequential recording of discrete values. The capacity of the device, calculated in bits, indicates how many values simultaneously in one recorded sample the sound is taken from. The higher the bit depth, the more closely the sound matches the original.
Any sound file can be presented, so that you can understand it more clearly, as a database. It has its own structure, the parameters of which are usually indicated at the beginning of the file. Then there is a structured list of values for certain fields. Sometimes instead of values there are formulas that allow you to reduce the file size. These files can only be read by specialized programs that contain a reading block.
RSM
PCM stands for pulse code modulation, which is translated as pulse code. Files with this exact extension are quite rare (I have only seen them in the 3D Audio program). But PCM is fundamental to all sound files. I would not say that this is a very economical method for storing data on a disk, but I think that you will never get away from this, and the volume of modern hard drives already allows you to ignore a couple of tens of megabytes.
DPCM
Research into economical storage of audio data on disk. If you come across this abbreviation, then know that you are dealing with difference RSM. The basis of this method is the completely justified idea that the calculations are much more cumbersome compared to the fact that you can simply indicate the difference values.
ADPCM
Adaptive DPCM. Agree that when simply specifying difference values, a problem may arise due to the fact that there are very small and very large values. As a result, no matter how super-accurate the measurements are, there is still a distortion of reality. Therefore, a scalability factor is added to the adaptive method.
WAV
The simplest storage of discrete data. I would say direct. One of the file types in the RIFF family. In addition to the usual discrete values, bit depth, number of channels and volume levels, wav can contain many more parameters that you most likely did not even suspect - these are: position marks for synchronization, the total number of discrete values, the order of playback of various parts of the audio file, and there is also space for you to place text information there.
RIFF
Resource Interchange File Format. A unique system for storing any structured data.
IFF
This storage technology originates from Amiga systems. Interchange File Format. Almost the same as RIFF, only there are some nuances. Let's start with the fact that the Amiga system was one of the first in which they began to think about software-sampling emulation of musical instruments. As a result, in this file the sound is divided into two parts: what should sound at the beginning and the element of what comes after the beginning. As a result, the beginning sounds once, then the second piece is repeated as many times as you need and the note can sound indefinitely.
MOD
The file stores a short sample of the sound, which can then be used as a template for the instrument. Simply put, a sample stitched into the synthesizer.
AIF or AIFF
Audio Interchange File Format. This format is common on Apple Macintosh and Silicon Graphics systems. Contains a combination of MOD and WAV.
AIFC or AIFF-C
The same AIFF, only with specified compression parameters.
AU
Again, the same race to save space. The file structure is much simpler than wav, but the data encoding method is specified there. The files weigh very little, which is why they have become quite widespread on the Internet. Most often you can find m-Law parameters 8 kHz - mono. But there are also 16-bit stereo files with frequencies of 22050 and 44100 Hz. This audio format is designed to work with audio on SUN, Linux and FreeBCD operating systems.
M.I.D.
A file that stores messages to the MIDI system installed on your computer or device.
MP3
The most scandalous format in recent times. To explain the compression parameters it uses, many people compare it to jpeg for images. There are a lot of bells and whistles in the calculations, which cannot be listed, but the compression ratio of 10-12 times speaks for itself. If they say that there is quality there, then I can say that there is not much of it. Experts talk about sound contouring as the biggest drawback of this format. Indeed, if you compare the music with the image, the meaning remains, but the small nuances are gone. The quality of MP3 still causes a lot of controversy, but for “ordinary non-musical” people the losses are not clearly noticeable.
VQF
A good alternative to MP3, albeit less common. It also has its drawbacks. Encoding a file into VQF is a much longer process. In addition, there are very few free programs that allow you to work with this file format, which, in fact, affected its distribution.
VOC
Eight-bit mono format from the SoundBlaster family. Can be found in a large number of old programs that use sound (not music).
NSOM
Same as VOC (eight bit mono), but only for Apple Macintosh.
UL
U-Law standard format. 8 kHz, 8 bit, mono.
R.A.
Real Audio or audio streaming. A fairly common system for transmitting sound in real time over the Internet. The transfer speed is about 1 KB per second. The resulting sound has the following parameters: 8 or 16 bits and 8 or 11 kHz.
SND
There are two types. One is the same AU for SUN and NeXT. The other is an 8-bit mono file for PCs and Macs with different sampling rates.
There are other types of sound files, but these are most likely files from various programs for creating and processing music. Basically, such files are read only by the program in which they were created.
Audio compression
Multimedia information consists of a huge amount of digital data that needs to be stored in a compressed form. Windows includes audio and video compression controls that work with one or more decompression modules called codecs (from Compression and DECompression). A large number of software codecs come with Windows. When you record or play back an audio or video file, Windows automatically uses the codec.Many sound and video cards have built-in hardware codecs. Windows uses the hardware codec first because it's faster and less CPU intensive. If there is no hardware codec, then Windows uses software codecs. If it couldn't find the codec, an error message will appear on the screen because the compressed file cannot be decompressed.
The Audio Compression Manager (ACM) program in Windows uses the following codecs to compress/decompress audio data.
- TrueSpeech Codec. Voice-centric codec developed by DSP Group. Use this codec only when compressing and transmitting over networks or telephone lines files containing voice recordings. TrueSpeech performs data compression not in real time, but decompression is performed in real time.
Microsoft GSM Audio Codec. A codec that compresses low-quality monochrome audio data in real time. Use this codec when recording voice messages, inserted into electronic mail (e-mail) messages. To record voice messages, you can use the Phonograph application.
Microsoft CCITT G.711 A-Law and U-Law Codec. This codec ensures compatibility between telephone standards in Europe and North America. It provides a data compression ratio of 2:1.
Microsoft ADPCM Codec. This codec provides both real-time and non-real-time compression, the latter being used by users of multimedia authoring systems. Audio files are better generated by a non-real-time codec.
IMA ADPCM Codec. This codec has been recommended by the Interactive Multimedia Association for use on various media platforms. It provides real-time compression and is similar to the Microsoft ADPCM codec.
Microsoft PCM converter. This converter allows you to play 16-bit audio on an 8-bit sound card. You can also use this codec in the case where you need to support a 1 MHz sampling rate for a card that supports a different sampling rate.
Digital Conversion Software
There are many codec programs designed specifically for converting digitally recorded files. The goal of each such program is the same - to compress the audio file with the least loss of quality and the highest compression ratio. Each of them has its own pros and cons: some have high compression quality, but the speed of this compression leaves much to be desired, others instantly encode but with a loss of quality, who would want to listen to a file with their favorite musical composition that groans, whistles and rustles like an old grandfather’s record? .The most popular codec programs are listed below.
Voice
The software consists of four modules that can work both on one computer and on different ones.The first module, operating in the Windows environment, is responsible for working with external equipment, directly recording from the telephone (radio) line and playing sound files into the telephone (radio) line.
Rice. 4. Voice dialog box
The second software module, responsible for compressing audio files, uses standard Wav file compression algorithms in its work. The compression algorithms used make it possible to pack incoming messages up to a level of 4Kbytes - 600bytes per second. Compression algorithms can be quickly changed depending on the required degree of compression and sound quality.
The third software module is responsible for maintaining the database (adding conversations to the database and automatically removing them from it as they age). The database stores information for a specified period of time, after which it is either archived or automatically deleted.
The last, fourth software module is designed to work with the database: searching for conversations, listening to them, rewriting and manually deleting them.
All modules run in 32-bit Windows environments. All software can simultaneously work with each other and with other Windows applications.
MPEG Encoder
One of the best codec programs of the past century.Fig.5. mpeg Encoder dialog box
One drawback of mpeg Encoder is that it takes a lot of time to compress a digital recording file. It takes about 25-40 minutes to process an audio file lasting about 3-5 minutes. But the wait is worth it - the quality is no different from the original.
The program consists of only one dialog box, which simplifies the work. No additional knowledge is required in the field of digital information conversion, etc., you specify the path to the outgoing file in the SOURCE field and in the TARGET field the final folder in which the compressed file in mp3 format will be located (by default). Set the quantization frequency, quality parameters - stereo or mono and... go ahead! Feel free to press the Encode button.
LameBatch
LameBatch is a simple wrapper written to make working with command lines mp3 encoders called LAME from Mark Taylor and company. The shell is based on a simple core.Rice. 6. Dialog box with LameBatc h program parameters
It contains only two tabs “Files” and “Settings”, in the latter you specify all the compression parameters you need.
Main features:
- Only one window (no pop-up windows from the encoder itself).
Individual encoding settings for each file.
The ability to change them for other files while encoding one.
All information about the progress of the process.
Checking files for acceptable format.
Various options queue sorting.
Simple writing of tags.
Possibility to postpone work indefinitely.
Different folder settings for results.
Checking overwrite and available space.
Drag and drop support.
Built into context menu Explorer.
Turn off the machine at the end of the procedure.
The list of programs and their advantages and disadvantages can be listed for a very long time. A lot of codec programs have been developed recently; as soon as you connect to the Internet, type “programs&encode&multimedia” in the search portal line, you will immediately receive a list of programs for processing audio and other files.
Conclusion
Let's talk a little about compression of audio files. Why this is needed is not worth saying much, I will only mention that widespread methods of compressing digital music data by 11–14 times have made it possible to incredibly push forward the software and hardware music industry, not to mention the fact that with high-quality music now V Internet problems, in general, no. You can find almost any composition. (In fact, of course, not just any one. Try to look for something non-trivial - Billy McKenzie, for example, or Bernie Marsden, it’s unlikely you’ll get anything. You can find mostly popular music or classics of the genre, and even then it’s far not all of it.Since the beginning of its rapid development (about two years ago), the open technology for compressing musical (sound) information has not undergone qualitative changes in compression technology. In other words, numerous music fans have to put up with fairly large files, since no progress is planned on this front. Today's limits for compression without significant loss of quality are about 11–12 times the original music file size. As you know, a CD with a standard sampling rate of 44,100 Hz (stereo, two bytes per amplitude value) can hold up to 74 minutes of sound - approximately 10 MB per minute.
With an average duration of a musical composition of 4 minutes, we have 40 MB of pure (uncompressed) sound. A lot of. A lot for the Internet. Having a modem with a speed of 33.6 KB/s and a full channel for downloading (i.e., ideally 3.5 KB/s), we will receive 40 MB only in 4–5 hours (usually this figure is 1.5–2 times more).
By applying compression to a music file without losing its main characteristics (stereo, sampling frequency during digitization 44,100 Hz, 2 bytes per amplitude sample), you can achieve a size reduction of 11–12 times. So instead of 40 MB, it will be only 3.8–3.9 MB. This is already quite acceptable. You can compress it even more, but then you noticeably lose in quality: the differences from the original become audible even to non-audiophiles. The limits mentioned here - 11 or 12 times - are already selected and tested quality/size criteria over the entire short history of using audio file compressor programs.
Literature
- Tom Sheldon. "Windows 95 couldn't be easier"
- A. Chizhov. “Napster is a panacea for MP3 music lovers”
- Internet. Websites:
- http://www.psf.by.ru
- http://www.submarine.ru
http://www.nsk.su/~sibell
http://www.sound_world.ru
http://www.sulaco.org
- yandex.ru
rambler.ru
altavista.com
yahoo.com
