what does mp4 mean

mp4 has two meanings: 1. The mp4 file format is a set of compression coding standards for audio and video information. It is a "dynamic image" under the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). "Expert Group". 2. MP4 player is a multi-functional player that integrates audio, video, picture browsing, e-books, and radio. It is a device that can play MPEG-4 files. It can also be called PVP (Personal Video Player) , PMP (Portable Media Player), PIA (Personal Image Assistant).

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

mp4 has two meanings: mp4 file format and mp4 player.

mp4 (file format)

MP4 is a set of compression coding standards for audio and video information, developed by the International Organization for Standardization (ISO) Developed by the Moving Picture Experts Group (MPEG) under the International Electrotechnical Commission (IEC), the first version was adopted in October 1998, and the second version was adopted in December 1999. The main uses of the MPEG-4 format are in online streaming, optical discs, voice transmission (video telephony), and television broadcasting.

MPEG-4 contains most of the functions of MPEG-1 and MPEG-2 and the advantages of other formats, and adds and expands support for Virtual Reality Modeling Language (VRML), targeting Composite files of objects (including sound effects, video and VRML objects), as well as digital rights management (DRM) and other interactive features. One of the features of MPEG-4 that is more advanced than MPEG-2 is that it no longer uses macro blocks for image analysis, but records changes on individuals in the image. Therefore, even if the image changes quickly and the bit rate is insufficient, it can No block screen will appear.

Features of MPEG-4

(1) Different encoding algorithms can be used for different objects, thereby further improving compression efficiency;

( 2) Objects are relatively independent, improving the reusability of multimedia data;

(3) Allowing users to operate on individual objects, providing unprecedented interactivity;

(4) Allowing users to The code rate is flexibly allocated between different objects. More bytes can be allocated to important objects, and fewer bytes can be allocated to minor objects, so that better results can be obtained at low code rates;

(5) Natural audio and video objects and synthetic audio and video objects can be easily integrated.

mp4 (multi-function player)

MP4 player is a kind of audio, video, picture browsing, e-book, radio An all-in-one multi-function player.

MP4 player is a device that can play MPEG-4 files. It can be called PVP (Personal Video Player, personal video player); it can be called PMP (Portable Media Player, portable media player); also It can be called PIA (Personal Imagine Assitant, personal image assistant).

MP4 player can transfer files through USB or 1394 port, easily download video files to the device for playback, and has an independent audio playback system to meet the needs of playing videos at any time.

Advantages

It can directly play high-quality video and audio, browse pictures, and be used as a mobile hard drive and digital bank; some products also have some very novel features , Practical functions, such as Archos AV420 can record video, it can save signals from DVD, TV and other devices in MPEG-4 format on the hard disk; Zhongji Chaowei’s upcoming MP4 player supports PIM management and wireless Network functions can play more roles after the wireless environment becomes popular. And most of the MP4 players we have seen have professional video functions such as video conversion, and have very complete video input/output ports, so the video files they carry can be played in many situations, although this is Some users who only use the player during travel have no more practical significance, but it is very useful for some users who often make video presentations, because the MP4 player can easily connect to output devices such as projectors and TVs. From the perspective of personal use, the biggest advantage of MP4 players is that they are compact, easy to carry, and can play videos anytime and anywhere. But there are more than just dedicated players that can meet these conditions, and handheld computers are a competitor. Although it is impossible to directly compare the two in terms of functionality, there is no essential difference between the two in terms of the video playback function of the machine. However, the handheld computer has more functions and is relatively cheaper. If you don't use MP4 players frequently, it might be a good idea to choose a handheld computer instead of MP4.

MP3 player, as the name suggests, is a music player tool that can play MP3 format. MP3 is the abbreviation of MPEG Audio Layer 3. The MPEG compression format is a set of standards for images and sounds developed by the Motion Picture Experts Group. MP3 is a new format designed to compress sound signals. Audio signal compression format standard. MP3 is a format that uses the third layer audio compression mode in the international standard MPEG to compress sound signals. It is also called "computer network music" in Chinese. The third layer audio compression mode in MPEG is much more complex than the first and second layer encoding, but the sound quality is higher than the first and second layers, and can even be compared with CD sound quality. The sampling rate of CD records is 44.1MHz, 16Bits, and the data volume is 1.4Mbps, while the corresponding MP3 data volume is only 112kbps or 128kbps, which is 1/12 of the original data volume. In other words, a traditional CD can store 10 times or more music, but to the human ear, the music effect is no different. MP3 itself is a compression and decompression calculation method. Processing of high-ratio sound information. The sound quality of the sound files it generates is close to CD, but the file size is only one-twelfth of CD. If a disc can store about 12-20 songs in CD format, and if saved in MP3 format, it can store nearly 100 songs. This is its charm. The original goal of MP3 was to reduce the file size so that data could be transmitted over the network and keep playback similar to the original. MP4 (also called MPEG-4) is a type of MPEG format and a compression method for moving images. This compression provides higher image quality with smaller files and is one of the most popular video file formats currently available (especially on the web). It is a compression standard for ultra-low bit-rate moving images and languages. It is used for real-time image transmission with a transmission rate lower than 64Mbps. It can not only cover low-frequency bands, but also develop towards high-frequency bands. MP4 provides a broader platform for multimedia data compression. It defines more of a format and an architecture rather than a specific algorithm. It can make full use of various multimedia technologies, including some tools and algorithms of compression itself, as well as image synthesis, speech synthesis and other technologies. MP4 has attracted widespread attention since the day it was proposed. Currently, the most popular compression methods used in MP4 are DivX and XviD. DVD programs that have been processed by MP4 technology represented by DivX or -ROM to save generated files. If the requirements are lowered, one disk can hold a movie of 100 minutes, and the picture quality at this time is still significantly better than VCD.

Advantages of smart MP4

1. Unlimited expansion of applications through the installation program

2. Strong DIYability

3. External hardware , as simple as a PC

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