How does MP4 work, and what does MP4 do?

The working principle of three-phase asynchronous motor. mp4(1)

1. MP4 is a device that can file MPEG-4 files, which can be called PVP (personal device); It can be called PMP (portable **** device); It can also be called PIA (Personal Image Assistant).

2、Now there is no specific definition of the function of MP4**,Although many manufacturers define it as a multi**audio-visual**,But in addition to the basic functions of listening to movies, it also supports****、Browsing**,Even some products can also go online。

3. Technically speaking, MP4 uses MPEG-2 AAC technology, which is referred to as A2B or AAC technology for short. It is characterized by a more perfect sound quality and a larger compression ratio (15:1-20:).

1)。It adds features such as perfect reproduction of stereo sound, bitstream effect sound scanning, multi-** control, noise reduction, etc., so that the sound quality of the CD can still be perfectly reproduced after audio compression.

4. MP4 (also known as MPEG-4) is a kind of MPEG format, which is a compression method for live images. With this compression, it is possible to provide high image quality with smaller files and is one of the most popular file formats (especially on the web).

5. The advantage of this format is that it can not only cover the low frequency band, but also develop to the high frequency band. MP4 has attracted a lot of attention since the day it was proposed, and the most popular compression methods for MP4 are DivX and XVID. After the MP4 technology processed by DIVX or XVID, the image and audio quality have not decreased much, but the volume has been reduced to a fraction of the original, and it is easy to use two ordinary CD-ROMs with a capacity of 650MB to save the generated files.

A single disc can hold a hundred and a few minutes of a movie, and the picture quality at this time is significantly better than that of VCD.

Introduction: What are the characteristics of MP4? MP4 is a set of compression and encoding standards for audio and information, and the following is the content I introduced to you, I hope it can help you!

1) Different coding algorithms can be adopted for different objects, so as to further improve the compression efficiency;

2) The objects are relatively independent, which improves the reusability of the sensitive and surplus data;

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

4) It allows flexible distribution of bit rate between different objects, and can allocate more bytes to important objects and fewer bytes to minor objects, so as to obtain better results at low bit rates;

With the advent of mp4 devices, people can make movies on the go, making the otherwise boring journey full of fun, and making it easy for you to go out and make presentations. As more and more digital manufacturers continue to launch MP4, many consumers are more and more eager to learn more about MP4 and related purchasing skills, today we will help friends with such needs———

Appearance: At present, the appearance of MP4 products on the market is mostly rectangular and has a large screen, which can be used by users to make good videos. The size and appearance of the MP4, as well as the distribution of the keys, are critical to consumer use.

The small body will make it easy for you to carry, and the distribution of the keys is also very particular, the left hand is suitable for operating the keys that are not often used, and the right hand is suitable for the operation of some commonly used functions

Digital processor: The mainstream MP4 on the market generally uses Texas Instruments and Intel's digital processing chips, consumers may wish to intuitively feel the **effect when purchasing**, and see whether the entire **MPEG4 format movie is smooth.

LCD Screen: The MP4 screens that can be seen on the market today are divided into inches and inches. They are all made of 260,000 colors. It's just that there are some products because of the LCD screen, the color saturation is not enough, so you must pay attention to the color clarity of the screen when choosing

Storage devices: MP4 on the market generally uses micro hard disks or flash memory cards as storage devices, at this stage, mainstream MP4 manufacturers mostly use micro hard disks as storage devices, micro hard disks generally have dozens of GB storage space, can store hundreds of MP4 movies. Although the flash memory MP4 has good shock resistance, the capacity limit is too large, and it is impossible to store MPEG4 movies, although it can be connected to an external flash memory card, but even if it is connected to an external 1G flash memory card, it can only put down two MPEG4 movies, and the cost is also very high. If you listen to MTV, you can choose flash MP4 plus external flash memory card

Determine the required functions: MP4 is the kind of full function among many digital products today, and the right choice can get more practical functions and add a lot of fun to life. First of all, the basic functions,****、**output、*****、Voice recorder、Mobile hard disk are the most basic functions of MP4,If you don't have these functions,Then you don't have to think about it.。。。

Categories: Computer, Networking, >> Hardware.

Analysis: I would like to look at this problem from the point of view of the purpose of mp4.

Then, whether MP4 can be popular depends on whether it can meet this demand.

The first thing to be eliminated should be that the screen is too small, and it's almost the same thing to show off, and really watching a movie is almost the same as being guilty.

Third, the picture quality is not good, or the ** is not smooth (this depends on the quality of the LCD and the decoding chip used), but also face elimination. If the picture is not clear, the colors are not correct, and the subtitles are not clear, who can watch the movie? In this way, many non-TFT LCDs such as STN and CSTN should not be able to mix.

And this is the mainstream display of low-cost MP4 at present.

Fourth, due to the above-mentioned quality requirements for watching movies, to have a good display quality, the **file must have a certain size, and the effect of the file with too large compression ratio will definitely not be better**. Therefore, if the storage capacity is too small, it also loses its practical value.

Fifth, the requirements for users: when watching movies, you must be staring at the screen, generally speaking, it is impossible to do anything else while watching movies (of course, eating snacks, pickling girls, etc. are not subject to this limit), therefore, it is not suitable for people who walk while recreation.

In fact, MP4 is suitable for people who do not get motion sickness in the car (can be in the car, on a boat, on a plane, etc.), suitable for people, and suitable for people who have leisure time when they are away on a business trip.

Filtered in this way, MP4's suitable population is significantly smaller than ***.

Obviously, you can listen to it at work, and do things while listening, without affecting your work efficiency, unless you have to answer it, listen to your boss's lectures, listen to lectures, lectures, etc.; Of course, *** is also suitable for walking, riding in the car, and any other leisure time.

In contrast, MP4 is much more restricted. You can't look at mp4 while working, and you can't read mp4 while walking, right? There are many similar cases.

Some people say that mp4 can also be listened to***. This is of course good, but please note that if it is necessary for the machine to be so big just to listen to ***? So, in order to be compatible with *** and MP4, do we have to carry a machine that is much larger in size than *** (mainly because MP4 requires a large display), but the battery life is not as good as *** (because MP4's large screen color LCD is very power-hungry)?

Finally, there is another point, that is, none of the current mainstream MP4 supports RM rmvb, the ** format with the most resources on the network. This is the most fatal problem of MP4, and it can be said that without solving this problem, MP4 will never be as popular as *** in China!

In fact, MP4 also faces the dual competition of PDA and second-hand laptops, and the future is far from clear.